Title of Invention	A PROCESS FOR THE PREPARATION OF NOVEL 5-[B-(10-PHENOTHIAZINYL) ETHYL]-1-(ACYL)-2,3,4-TETRAZOLES
Abstract	The present invention describes to a process for the preparation of novel 5-[(β-10 phenothiazinyl)ethyl]-1-(acyl)-2,3,4-tetrazoles.The preparation connprises of three steps, where the first step involves in the preparation of phenothiazine propionitrile the second step involves in the preparation of 5-[(β-10 phenothiazinyl)ethyl]-1,2,3,4-tetrazoles and the third step involves in the preparation of 5-[(β-10 phenothiazinyl)ethyl]-1-(acyl)-2,3,4-tetrazoles. In the first step phenothiazine was cyanoethylated in presence of the catalyst Triton B. In the second step, cyanoethylated phenothiazine was refluxed with dimethyl formamide, ammonium chloride and sodium azide for 7 hours to obtain 5-[(β-10 phenothiazinyl)ethyl]-1-2,3,4-tetrazoles. In step three, a new series of substituted tetrazoles were synthesized by reacting it with appropriate acyl chlorides. All the novel substituted tetrazoles were found to possess antimicrobial, analgesic and anticonvulsant activities.

Title of Invention

A PROCESS FOR THE PREPARATION OF NOVEL 5-[B-(10-PHENOTHIAZINYL) ETHYL]-1-(ACYL)-2,3,4-TETRAZOLES

Abstract

The present invention describes to a process for the preparation of novel 5-[(β-10 phenothiazinyl)ethyl]-1-(acyl)-2,3,4-tetrazoles.The preparation connprises of three steps, where the first step involves in the preparation of phenothiazine propionitrile the second step involves in the preparation of 5-[(β-10 phenothiazinyl)ethyl]-1,2,3,4-tetrazoles and the third step involves in the preparation of 5-[(β-10 phenothiazinyl)ethyl]-1-(acyl)-2,3,4-tetrazoles. In the first step phenothiazine was cyanoethylated in presence of the catalyst Triton B. In the second step, cyanoethylated phenothiazine was refluxed with dimethyl formamide, ammonium chloride and sodium azide for 7 hours to obtain 5-[(β-10 phenothiazinyl)ethyl]-1-2,3,4-tetrazoles. In step three, a new series of substituted tetrazoles were synthesized by reacting it with appropriate acyl chlorides. All the novel substituted tetrazoles were found to possess antimicrobial, analgesic and anticonvulsant activities.

Full Text	The present invention particularly relates to a process for the preparation of novel 1,5-disubstituted-1,2,3,4-tetrazoles useful as antimicrobial, analgesic and anticonvulsant. More particularly the present invention relates to the preparation of 5-[0-10 phenothiazinyl) ethyl]-1-(acyl), 2, 3, 4-tetrazole. The survey of literature reveals that synthesis and evaluation of tetrazoles have been extensively carried out and they are reported to possess antimicrobial activity, antiinflammatory activity, analgesic activity, antihypertensive activity, antiallergic activity, antineoplastic activity, diuretic activity, herbicidal activity. Central Nervous system activity and hormonal activity. Several cephalosporin derivatives (Matrindale, The Extra Pharmacopoeia, Twenty Seventh Edition, The Pharmaceutical Press.London, 1977, 1105. Drugs of Today, 1978,14, 548) having tetrazole moiety as a substituent at position 3,7 or both are reported to possess antibacterial activity. The most promising compounds among them were Cephazolin sodium, Ceftezole and Cephamandole. Broadspectrum of activity was reported for Cefazaflur (Demarinis R.IVI., l-foover J.R.E., Dunn G.L., Actor P., Uri J.V and Weisbach J.A., J. Antibiot.,1975, 28,463) Dipotassium a(-tetrazol-5yl) benzyl penicillin exhibited in vitro antibacterial activity similar to that of carbenicillin (Essey J.IVI., J. IVIed. Chem., 1969,12, 703) Witkowshi et al. (Witkowshi J.T., Robins R.K., Sidwell R.W. and Simon L.N., J. Med. Chem., 1972, 15, 1150) reported broad spectrum viral activity for virazoie). Virucidal activity was found in 6-(aminomethyl-5-tetrazolyl) benzothiazole (Holbova E. and UherM., Chem. Zvesti., 1982, 36, 253). Sangal et al. (Sangal S.K. and Ashok Kumar., J. Indian. Chem. Soc, 1986, 63, 351-353) synthesized some novel tetrazolyl sulphides and screened them for fungicidal activity. IVIicher Barreau et al. (Micher Barreau, Micheal Kryvenko, Marc Pierre, Lavargue and Auguste Techer, Chem. Abstr., 1992, 116. 151771w) synthesized novel tetrazoles containing oxazole derivatives and found that they possess antiinflammatory activity. A series of 5-(2-anilino phenyl) tetrazoles(Juby P.P., Hudyma T.W. and Brown M., J. Med. Chem., 1968, H, 111) were synthesized as analogues of flufenamic acid and these had activity comparable both that of corresponding acids. The two most active anti-inflammatory tetrazoles were 5-[2-(3-trifluro methyl anilino)-phenyl] tetrazole and 5-[2-(2,6-dichlor-3-methyl aniline phenyl)tetrazole]. A series of 1-substituted 3-tetrazol-5yl methyl indoles as analogues of indomethacin have been synthesized (Juby P.P. and Hudyma T.W., J. Med. Chem., 1969,12, 369). The most active antiinflammatory tetrazole was 1-(4 chloro benzoyl)-3-(tetrazol-5yl methyl)indole. A number of 2 phenyl 3-mercapto indole compounds containing a tetrazole group have been synthesized (Bazile Y., Bras J., De Cointet P., Nathavong S., Pigerol C, Broil M., Eymard P., Webence J. and Fournier J., Eur. J. Med. Chem. Chim. Therap., 1977, 12, 525) and tested for antiinflammatory activity. Only one compound, 2 phenyl-3-(tetrazole 5 yl-methyl thio) indole exhibited noticeable activity. A number of aryl tetrazolyl alkanoic acids (Buckler R.T., Hayao S., Lorenzetti O.J., Sancillo L.F., Hartzler H.E. and Strycker W.G., J. Med. Chem., 1970, 13, 725. Buckler, U.S. Patent., 1971, 3, 578, 674: Chem. Abstr. 1971, 75, 36048) have been synthesised and maximum antiinflammatory activity was found in those members of the series which have meta halogenated aromatic substituents and a propionic acid residue at position 2 of the tetrazole ring. Substituted benzylidine derivatives (Raman K., Parmar S.S., Pandey B.R. and Bartwal J.P., Indian. J. Pharm. Sci., 1979, 41, 38. Raman K., Parmar S.S., Kumar S. and Brumleve S.J., Pharmacology., 1978,17, 56; Chem. Abstr, 1978, 89i 36466) of 2-hydroazino carbomyl methyl-5-phenyl tetrazole are reported to be active. Certain carbamide derivatives are also reported to be active as antiinflammatory agents (Kishore V., Parmar S.S., Gildersleeve D.L., J. Heterocycl. Chem., 1978,15,1335). A number of aryloxyethyl, anilinoethyl and anilldomethyl tetrazoles have been prepared and tested for antiinflammatory activity (Shukla J.S., Ahmed J. and Saxena S., Indian. J. Pharm. Sci., 1979, 41, 70). 5-(p-p-methoxy phenoxy ethyl)tetrazole was found to be most active. Shishoo et at. (Shishoo C.J., Devani M.B., Karvekar M.D., Vlias G.V., Anantham S. and Bhaati V.S., Ind. J. Chem., 1982, 21B. 666-668) synthesized tetrazoloil,5e] thieno[3,2 e]pyrimldlnes and evaluated the anti-inflammatory activity. A few 5(indan-1'yl) tetrazoles were synthesized and screened for antiinflammatory and related biological activities. 5(indan-1'yl) tetrazole was found to be superior to phenyl butazone in established adjuvant Induced arthritis and yeast induced pyrexia biomodels in rats (Ray S.M. and Lahiri S.C, J. Indian Chem. See, 1990, 67, 324-326.83. Okabayashi T., Kano H. and Makisumi Y., Chem. Pharm. Bull., 1960,8,157). Tetrazoles (Wazir V., Singh G.B., Singh S., Gupta R. and Kachroo P.L., J. Indian. Chem. Sec, 1991, 68, 305) 1,4-dlhydro-3-pyridyltetrazoles(Kumar P. and Knaus E.E., Drug. Des. Discovery., 1991, 7, 287) Furyltetrazoles (Janda L., Voticky Z., Svetlik J., Grimove J. and Maturova E., Coll. Czech. Chem. Commun., 1984, 49, 1505) and 2,5-disubstituted tetrazole (Pande K., Tendon M., Bhalla T.N. and Bharthwal J.P., Indian. J. Chem., 1984, 23B. 1133) showed antiinflammatory activity against carrageenin induced rat paw edema. 5-lmino-1-(2 hydroxy-2-arylethyl)tetrazoles have also been mentioned as antinflammatory, analgesic and hypothermic agents (Mugnaini A., Friz L.P, Provincaili E., RugarIi P., Olivi A., Zefelippo E., Almirante L. and Murmann N., Boll. Chim. Farm., 1966, 105, 596; Chem. Abstr., 1967, 66, 75958). A weak CNS depressant and analgesic activity was observed (Crawley L.S. and Safir S.R., U.S. Patent. 1976, 3,966,756;Chem.Abstr., 1976, 85, 192783. Gebert U., Musil J. and Weber R.O., Ger. Often.1978, 2, 650,231; Chem. Abstr., 1978, 89, 75374) for certain tetrazole analogues. Martin et al. (Martin .W., Biswanathi D., Thomas Zydowsky M., Daniel Kerkamnn J., John Debernein F., Sand Roserburg H., Kaumi Shiosaki H., Fatima Basha Z. and Andrew Tasker., Abbot. Laboratories, U.S. Pat.1993, 5, 250,548; Chem. Abstr., 1994, 121, 628) synthesized [(tetrazolyl biphenyl) methyl amino]pyridine carboxylate and evaluated their angiotensin receptor antagonist action. Of thirtyfour tetrazole derivatives synthesised by Cosgrove et al. (Cosgrove C.E. and Laforge R.A., J. Org. Chem., 1956, 21, 197) sixteen produced a considerable drop in blood pressure for at least five min in anaesthesised dogs. Several 5-dialkyl amino alkyl tetrazoles showed potent alpha anti-adrenergic activity(Hayao S., Havera H.J., Strycker W.G., Leipzig T.J. and Rodriguez R., J, Med. Chem., 1965,10, 400). Reaction of N-phenylpiperazine with acrylonitrile produces nitrile and conversion of this nitrile to a tetrazole ring via 1,3 diploar addition process by sodium azide under ammonium chloride catalysis produces zolterine an antihypertensive agent (Stryker W.G. and Hayao S., Belgium Patent. 1965, 661, 1390; Chem.Abstr. 1965, 63,18114e). Gupta et al. (Gupta A.K.S., Bhattacharya T. and Rastogi A., Indian. J. Chem. 1985, 24B. 578) reported the synthesis and in vitro evaluation of 2-[(1-aryl-1 H-tetrazol-5-yl)thio-N-[(arylamino)carbonyl]acetamides as acetylcholinesterase inhibitors. Milcent et al. [Mllcent R., Lebreton L., Mazouz. and Burstein C, FR2631827 Al 1 Dec 1989; Chem. Abstr. 113,191368k] reported 2,5-disubstituted tetrazoles as type B monoamine oxidase (MAO) inhibitors. 5-(3-p-cyanophenoxy-2 hydroxy-1-propoxy)-2-(1 H-tetrazol-5-yl) chromone sodium was tested for anti allergic activity (Francis D.I., Spicer J.W., Taylor W.A. and Warren B.T., Antiallergic Chromones, Fifth International Symposium on Medicinal Chemistry, Paris, 1976,19-22). Several 3-(terazol-5yl) chromones have been reported to be active as antiallergic agents. Among these the derivative with substituents at 6 and 8 positions and the benzo analogues were found to be very active as anti allergic agents (Nohara A., Tetrahedron letters., 1974,1187). Several tetrazolium nitrogen mustards have been prepared and evaluated for antineoplastic activity (Tsov K.C. and Su H.C.F., J. Med. Chem., 1963, 6, 693). 6-chloro tetrazolo [1,5-b]pyridazine was reported to inhibit the growth of He La cells and also showed activity against experimental tumor(Bary V.C., Conalty M.C., O'sullivan J.P. and Twomey., Pro. 9* Int. Congr. Chemother., 1977, 8, 103; Chem. Abstr., 1977, 87, 23287). Tetrazole analogues of potent non-steriodal oestrogens have been prepared (Crenshaw R.R., Luke G.M. and Bialy G., J. Med. Chem., 1972, 15, 1179) by replacing the respective carboxyl group with a tetrazole moiety with the hope of dissociating antifertility and oestrogenic activities but the compounds were inactive. The tetrazole analogues of progesterone and testosterone, namely, 7 a-aza-B-homo-4-pregneno [7a,7d]tetrazole-3,20-dione and oxo-7a-aza-B-homo-4a-androsteno [7a,7d]tetrazol-17-pyl acetate have been prepared and evaluated for hormonal activity (Singh H., Bhutani K.K., Malhotra R.K. and Paul D., Experlentia, 1978, 34, 557. Singh H., Bhutani K.K., IVIalhotra R.K. and Paul D., J. Chem. See, 1979,1, 3166). A tetrazolyl sulphonamide, 5-(4-chloro-5-sulphamoyl-2-thienylamino phenyl) tetrazole was synthesised and evaluated for diuretic acitivity (Popelak A., Lerch A., Stach K., Rosesch E. and Hardebeck K., Ger. Offen.,1975, 2, 423, 550, 90740. Kuhn R., Hardebeck K., Heinemann H. and Osmers K., Ger. Offen., 1975, 2, 423 550; Chem. Abstr. 1976, 84, 49849). The main objective of the present invention is to provide novel 5[(p-10 phenothiazinyl) ethyl] 1,2,3,4 tetrazoles of the following general formula 4 (Figure 1) useful as antimicrobial, analgesic and anticonvulsant. The another objective of the present invention is to provide a process for the preparation of novel 5-[(p-10 phenothiazinyl) ethyl]-1-(acyl), 2, 3, 4 - tetrazoles. Yet another objective of the present invention is to provide compounds useful in the treatment of microbial infections, convulsions and as analgesic. Accordingly, the present invention provide a process for the preparation of novel 5-[(p-10 phenothiazinyl) ethyl]-1-(acyl), 2, 3, 4-tetrazoles of the general formula (Figure 1), useful as antimicrobial, analgesic and anticonvulsant, comprises the In an embodiment of the present invention the phenothiazines used are selected from phenothiazine 2-chlorophenothiazine, 2-methylphenothiazine, 2-ethylphenothiazlne and 2-trifuormethylphenothiazine. In another embodiment of the present invention the Triton B was selected as catalyst for cyanoethylation. In yet another embodiment of the present invention dimethyl formamide, ammonium chloride and sodium azide was selected. In yet another embodiment of the present invention the acid chloride used are selected from aliphatic acid, aromatic acid and aryl acyl chlorides like acetyl chloride, propionyl chloride, benzoyl chloride, p-chlorobenzoyl chloride, o-nltrobenzoyl chloride, p-nitrobenzoyl chloride, p-hydroxy benzoyl chloride, p-aminobenzoyl chloride, p-methylbenzoyl chloride, p-methoxybenzoyl chloride, phenyl acetyl chloride and p-toluene benzene sulphonyl chloride. In a further embodiment of the present invention the solvents employed for extraction of the compound from the reaction mixture are selected from the group consisting of chloroform, dichloromethane and ethyl acetate. In a further embodiment the recovery and purification of the compound produced is effected by chromatography using eluant selected from the group consisting of hexane, chloroform, ethyl acetate, toluene, methanolic or ethanolic toluene, benzene, methanolic or ethanolic benzene and a mixture thereof. The compounds were also tested for their antimicrobial, analgesic and anticonvulsant activity. The process of the present invention is already explained by the reaction scheme depicted in figure 1. The representative compounds of the formula 4 prepared by the process of the invention are as follows: Compound 1 1-acetyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 2 1-propionyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 3 1-benzoyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 4 1-p-chloro benzoyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 5 1-o-nitro benzoyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 6 1-p-nitro benzoyl-5-[(P-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 7 1-p-hydroxy benzoyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 8 1-p-amino benzoyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 9 1-p-methyl benzoyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 10 1-p-methoxy benzoyl-5-[(P-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 11 1-phenylacetyl -5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 12 1-Toluene-p-sulphonyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole The advantages of the present invention is that it provides a new class of compounds which are antimicrobial, analgesic and anticonvulsant and are much simpler than existing fluconazole, the standard drug. The starting materials of the compounds of the present invention are cheap and easily available. The process described here is simple, economically feasible and eco-friendly. The invention is illustrated by the following examples, which is no way represent as limitation thereof. Example 1 10-Phenothiazinvl propionitrile Phenothiazine (9.95 g, 0.05 mole) was mixed with 12.5 ml of acrylonitrile in a 100 ml round bottomed flask and cooled in ice bath. A crystal of resorcinol was added to prevent polymerisation. Triton B (2 ml) was added dropwise with shaking. A vigorous reaction was set in. It was allowed to subside and then the contents of the flask were refluxed on a steam bath for 2 h. The solution was cooled, extracted with ethylene dichloride and dried over anhydrous sodium sulphate. The dried nitrile was recrystallised (yleld 82 %) from ethanol, melted at 159-160°C. Example 2 5-r(B-10- Phenothiazinyl) ethvl 11.2.3.4 tetrazole A mixture of phenothiazinyl propionitrile (3.3 g, 0.01 mole), sodium azide (1 g, 0.01 mole) dimethylformamide (10 ml) and ammonium chloride (5.3 g, 0.1 mole) were taken in a 100 ml round bottomed flask. The contents were heated in an oil bath for 7 h at 125°C. The solvent was removed at reduced pressure. The reaction mixture was dissolved in 100 ml of distilled water and carefully acidified with concentrated hydrochloric acid to pH2. The solution was cooled to 5°C in ice bath. The product was rennoved by filteration, washed with several portions of water and dried. The crude product was recrystallized{yleld 77 %) from aqueous methanol, melted at 148-149°C. Example 3 1-Acetyl-5-r(B-10 phenothiazinvh ethvIM .2.3.4 tetrazole Acetic anhydride was used for the synthesis of N-acetyl derivative of tetrazole since acetyl chloride is not satisfactory as it forms equivalent quantity of tetrazole hydrochloride. Refluxed gently the 5 - [(P-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1 g, 0.0025 mole) under a short air condenser with acetic anhydride (3 g, 0.03 mole) for 15 minutes. Cooled the reaction mixture and poured it into 20 ml of cold water. Boiled to decompose the excess acetic anhydride. Cooled and filtered the insoluble acetyl derivative and washed with little cold water. The dried compound was recrystallised (yleld 88 %) from dilute ethanol, melted at 134-135°C. Example 4 1-Propionvl-5-r(B-10 phenothiazinvn ethyl] .2.3.4 tetrazole Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and propionyl chloride (4.2 g, 0.045 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of propionyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any propionic acid, which may be present. The dried compound was recrystallised (yleld 54 %) from dilute ethanol, melted at 125-126°C. Example 5 1-Benzovl-5-r(B-10 phenothiazinvn ethvlM.2.3.4 tetrazole Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and benzoyl chloride (4.2 g, 0.03 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of benzoyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any benzoic acid, which may be present. The dried compound was recrystallised (yleld 59 %) from dilute ethanol, melted at 106-107°C. Example 6 1-p-Chloro benzovl-5-r(B-10 phenothiazinyl) ethvIM .2.3.4 tetrazole Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and p-chlorobenzoyl chloride (3.5 g, 0.02 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of p-chlorobenzoyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any p-chlorobenzoic acid, which may be present. The dried compound was recrystallised(yleld 67 %) from dilute ethanol, melted at 168-169°C. Example 7 1-o-Nitro benzovl-5-r(B-10 phenothiazinyl) ethyll-l.2.3.4 tetrazole Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and o-nitrobenzoyl chloride (3.71 g, 0.02 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of o-nitrobenzoyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any o-nitrobenzoic acid which may be present. The dried compound was recrystallised(yleld 71 %) from dilute ethanol, melted at 109-110°C. Example 8 1-p-Nitro ben2ovl-5-r(B-10 phenothiazinvl) ethvIM.2.3.4 tetrazole Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and p-nitrobenzoyl chloride (3.71 g, 0.02 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of p-nitrobenzoyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any p-nitrobenzoic acid, which may be present. The dried compound was recrystallised (yleld 69 %) from dilute ethanol, melted at 171-172°C. Example 9 1-p-hvdroxvbenzovl-5-r(B-10 phenothlazlnvn ethyl] .2.3.4 tetrazole Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and p-hydroxybenzoyl chloride (3.13 g, 0.02 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of p-hydroxybenzoyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any p-hydroxybenzoic acid, which may be present. The dried compound was recrystallised (62 %) from dilute ethanol, has melting range >210°C. Example 10 1-p-Aminobenzovl-5-r(B-10 phenothiazinvl) ethvIM.2.3.4 tetrazole Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and p-aminobenzoyl chloride (3.11 g, 0.02 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of p-aminobenzoyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any p-aminobenzoic acid, which may be present. The dried compound was recrystallised(yleld 62 %) from dilute ethanol, has melting range >210°C. Example 11 1-/o-Methvlbenzovl-5-r(B-10 Phenothiazinyl) ethvlM.2.3.4 tetrazole Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and p-methylbenzoyl chloride (3.1 g, 0.02 mole) was added to it. Shaken the mixture vigorously In a stoppered test tube. When the odour of p-methylbenzoyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any p-methylbenzoic acid, which may be present. The dried compound was recrystallised(yleld 64 %) from dilute ethanol, melted at 121-122°C. Example 12 1-p-Methoxvbenzovl-5-r(3-10 phenothiazinvl) ethvn-1.2.3.4 tetrazole Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and p-methoybenzoyl chloride (3.1 g, 0.02 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of p-methoxybenzoyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any p-methoxybenzoic acid, which may be present. The dried compound was recrystallised(yleld 68 %) from dilute ethanol, melted at 158-159°C. Example 13 1-Phenvlacetvl-5-r(B-10 phenothiazinvl) ethvn-1.2.3.4 tetrazole Dissolved 5-[((3-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole( 1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and phenylacetyl chloride (3.1 g, 0.02 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of phenylacetyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any phenylacetic acid, which may be present. The dried compound was recrystallised(yleld 64 %) from dilute ethanol, melted at 127-128°C. Example 14 1-Toluene-p-sulphonvl-5-r(B-10 phenothiazinvl) ethvn-1.2.3.4 tetrazole Treated 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1 g, 0.025 mole) with 20 ml of 10 % sodium bicarbonate solution and toluene-p-sulphonyl chloride (4.75 g, 0.025 mole) was added in small portions with constant shaking. The contents were shaken vigorously in a stoppered test tube to remove the excess of acid chloride. The contents were acidified with dilute hydrochloric acid and filtered. The dried compound was recrystallised (yleld 60 %) from dilute ethanol, melted at 97-98°C. Example 15 Evaluation of Antibacterial Activity The plates containing nutrient agar were seeded with different test bacteria aseptically with the help of sterile swab. Well of 6 mm in diameter were made with sterile borer. Each well were added with 50 \|al of the solution of synthesised compounds using micropipette. They were allowed to diffuse for about 1 h. One well for each test microorganism was served as solvent control. The plates were then incubated at 37°C for 24 h and the diameter of zone inhibition was measured in four directions and the average was taken into account and compared with standard antibacterial drug ciprofloxacin. (Table-1) Evaluation of Antifungal Activity The plates containing sabouraud dextrose agar were seeded with Aspergillus niger NCIM 1054 and Candida albicans NCIM 3102 aseptically with the help of sterile swab. Well of 6 mm in diameter were made with sterile borer. Each well were added with 50 il of the solution of synthesised compounds using micropipette. They were allowed to diffuse for about 1 h. One well for each test microorganism was served as solvent control. The plates were then incubated at 28°C for 48 h and the diameter of zone inhibition was measured in four directions and the average was taken into account and compared with standard antifungal drug Fluconazole. (Table-1) Example 16 Evaluation of Analgesic activity bv a.Acetic acid induced writhing method The method suggested by Witkin et al. was adopted for the study. Swiss strain albino mice of either sex weighing 25-30 g were used for this study. The animals were then divided into 28 groups of 10 mice each. Tween 80 suspensions (10 %v/v) of the test compounds were administered intraperitoneaily in dose of 25 mg/kg(bw). The control group of animals was given only 10 %v/v Tween 80(0.5 ml) suspension. One group of animals was given with Nimesulide as standard, intraperitoneaily in a dose of 10 mg/kg(bw). After 20 minutes of the administration of the test compounds, all the groups of mice were given with the writhing agent 3 % v/v aqueous acetic acid in a dose of 2 ml/kg(bw), intrperitoneally. Writhing is defined as stretch, torsion to one side, abdominal contractions, trunk twist respose and extension of hind limbs. The writhings produced in these animals were counted for 15 minutes and the number of writhings produced in treated groups was compared with those in the control group. (Table-2) The results were analysed statistically by student't' test. Dose: 25 mg/kg for all the test compounds and 10 mg/kg for Nimesullde Comparison with Control Highly significant P b.Hot Plate Method The method of Eddy and Leimbach, with modification by Aparicio was followed. Swiss strain albino mice of either sex weighing 25-30 g were used for the study and they were deprived of solid food and water for 24 h, prior to the administration of compounds. The animals were selected based on the reaction time and for this, they were placed on a hot plate at 55 ± 0.5°C. Animals showed the reaction time > 10 sec was rejected. When a mouse is placed on a plate at 55 ± 0.5°C, it takes 4-5 seconds, to lick its hind paws or tries to jump out in an attempt to escape the heat. The time observed was called normal reaction time. After selection, the animals were divided into 28 groups of 6 mice each. Tween 80 suspensions (10 %v/v)of the test compounds were administered intraperitoneally in dose of 25 mg/kg(bw). The control group of animals was given only 10 %v/v Tween 80(0.5 ml) suspension. One group of animals was given with Morphine sulphate as standard, intraperitoneally in a dose of 5 mg/kg (bw). The pain threshold was measured by using Hot Plate for fifteen minutes, thirty minutes after the administration of the drug and thereafter at hourly intervals for two hours. (Table-3) Dose; 25 mg/kg for all the test compounds and 5 mg/kg for Morphine sulphate Comparison with Control Highly significant P Example 17 Evaluation of Anticonvulsant Activity by a.Maximal Electroshock Induced Convulsion method Goodman et al. method was adopted for studylng anticonvulsant activity. Swiss strain albino rat of either sex (150 - 210 g) were given supramaximal electroshock through ear electrodes of 150 mA for 0.2 sec by a Techno(Lucknow) electroconvulsiometer. Animals that showed positive hind limb tonic extensor response were selected and they were divided into 28 groups of six rats each. One group was treated with standard drug phenytoin(25 mg/kg) and the other control group was treated only with 10 %v/v Tween 80. Then the synthesized compounds 1-26 suspended in 10 %v/v Tween 80 were administered intraperitoneally in a dose of 25 mg/kg one hour before seizure induction. Onset times(sec) for myoclonic jerks, clonus, extensor and stupor phases and death were noted. Percentage mortality was also recorded. The protective index was observed as the abolision or reduction of the hind limb tonic extension component of the seizure. (Table-4) Dose: 25 mg/kg for all the test compounds and phenytoin Comparison with Control Highly significant P ** insignificant P b.Strychnine Induced Convulsion method Chen et al. method was followed to evaluate the anticonvulsant activity for the synthesised compounds. Swiss albino mice of either sex weighing 25-30 g were divided into 15 groups with 6 mice in each group. Tween 80 suspensions(10 % v/v) of the synthesised compounds were administered intraperitoneally in a dose 25 mg/kg prior to the administration of strychnine( 2mg/kg, b.w). The control group of animals was given only with 10 %v/v Tween 80 suspension(0.5 ml). The percentage mortality was noted after 15 min of strychnine administration for each group. (Table- I Claim 1 .A process for the preparation of novel 5-[(β-10 phenothiazinyl) ethyl]-1-(acyl),2,3, 4-tetrazoles of the general fornnula (Figure 1), useful as antimicrobial, analgesic and anticonvulsant, comprises the following steps. 2.A process as claimed in claim I wherein the phenothiazines used are selected from phenothiazine or substituted phenothiazine 3.A process as claimed in claim I wherein the catalyst for cyanoethylation is selected as Triton B. 4. A process as claimed in claim I wherein dimethyl formamide, ammonium chloride and sodium azide are selected. 5. A process for the preparation of novel 5-[(p-10 phenothiazinyl)ethyl]-1-acyl,2,3,4- tetrazoles substantially as herein described with reference to examples

Full Text

The present invention particularly relates to a process for the preparation of novel 1,5-disubstituted-1,2,3,4-tetrazoles useful as antimicrobial, analgesic and anticonvulsant. More particularly the present invention relates to the preparation of 5-[0-10 phenothiazinyl) ethyl]-1-(acyl), 2, 3, 4-tetrazole.
The survey of literature reveals that synthesis and evaluation of tetrazoles have been extensively carried out and they are reported to possess antimicrobial activity, antiinflammatory activity, analgesic activity, antihypertensive activity, antiallergic activity, antineoplastic activity, diuretic activity, herbicidal activity. Central Nervous system activity and hormonal activity.
Several cephalosporin derivatives (Matrindale, The Extra Pharmacopoeia, Twenty Seventh Edition, The Pharmaceutical Press.London, 1977, 1105. Drugs of Today, 1978,14, 548) having tetrazole moiety as a substituent at position 3,7 or both are reported to possess antibacterial activity. The most promising compounds among them were Cephazolin sodium, Ceftezole and Cephamandole. Broadspectrum of activity was reported for Cefazaflur (Demarinis R.IVI., l-foover J.R.E., Dunn G.L., Actor P., Uri J.V and Weisbach J.A., J. Antibiot.,1975, 28,463)
Dipotassium a(-tetrazol-5yl) benzyl penicillin exhibited in vitro antibacterial activity similar to that of carbenicillin (Essey J.IVI., J. IVIed. Chem., 1969,12, 703)
Witkowshi et al. (Witkowshi J.T., Robins R.K., Sidwell R.W. and Simon L.N., J. Med. Chem., 1972, 15, 1150) reported broad spectrum viral activity for virazoie).
Virucidal activity was found in 6-(aminomethyl-5-tetrazolyl) benzothiazole (Holbova E. and UherM., Chem. Zvesti., 1982, 36, 253).

Sangal et al. (Sangal S.K. and Ashok Kumar., J. Indian. Chem. Soc, 1986, 63, 351-353) synthesized some novel tetrazolyl sulphides and screened them for fungicidal activity.
IVIicher Barreau et al. (Micher Barreau, Micheal Kryvenko, Marc Pierre, Lavargue and Auguste Techer, Chem. Abstr., 1992, 116. 151771w) synthesized novel tetrazoles containing oxazole derivatives and found that they possess antiinflammatory activity.
A series of 5-(2-anilino phenyl) tetrazoles(Juby P.P., Hudyma T.W. and Brown M., J. Med. Chem., 1968, H, 111) were synthesized as analogues of flufenamic acid and these had activity comparable both that of corresponding acids. The two most active anti-inflammatory tetrazoles were 5-[2-(3-trifluro methyl anilino)-phenyl] tetrazole and 5-[2-(2,6-dichlor-3-methyl aniline phenyl)tetrazole].
A series of 1-substituted 3-tetrazol-5yl methyl indoles as analogues of indomethacin have been synthesized (Juby P.P. and Hudyma T.W., J. Med. Chem., 1969,12, 369). The most active antiinflammatory tetrazole was 1-(4 chloro benzoyl)-3-(tetrazol-5yl methyl)indole.
A number of 2 phenyl 3-mercapto indole compounds containing a tetrazole group have been synthesized (Bazile Y., Bras J., De Cointet P., Nathavong S., Pigerol C, Broil M., Eymard P., Webence J. and Fournier J., Eur. J. Med. Chem. Chim. Therap., 1977, 12, 525) and tested for antiinflammatory activity. Only one compound, 2 phenyl-3-(tetrazole 5 yl-methyl thio) indole exhibited noticeable activity.
A number of aryl tetrazolyl alkanoic acids (Buckler R.T., Hayao S., Lorenzetti O.J., Sancillo L.F., Hartzler H.E. and Strycker W.G., J. Med. Chem., 1970, 13, 725. Buckler, U.S. Patent., 1971, 3, 578, 674: Chem. Abstr. 1971, 75, 36048) have been synthesised and maximum antiinflammatory activity was found in

those members of the series which have meta halogenated aromatic substituents and a propionic acid residue at position 2 of the tetrazole ring.
Substituted benzylidine derivatives (Raman K., Parmar S.S., Pandey B.R. and Bartwal J.P., Indian. J. Pharm. Sci., 1979, 41, 38. Raman K., Parmar S.S., Kumar S. and Brumleve S.J., Pharmacology., 1978,17, 56; Chem. Abstr, 1978, 89i 36466) of 2-hydroazino carbomyl methyl-5-phenyl tetrazole are reported to be active. Certain carbamide derivatives are also reported to be active as antiinflammatory agents (Kishore V., Parmar S.S., Gildersleeve D.L., J. Heterocycl. Chem., 1978,15,1335).
A number of aryloxyethyl, anilinoethyl and anilldomethyl tetrazoles have been prepared and tested for antiinflammatory activity (Shukla J.S., Ahmed J. and Saxena S., Indian. J. Pharm. Sci., 1979, 41, 70). 5-(p-p-methoxy phenoxy ethyl)tetrazole was found to be most active.
Shishoo et at. (Shishoo C.J., Devani M.B., Karvekar M.D., Vlias G.V., Anantham S. and Bhaati V.S., Ind. J. Chem., 1982, 21B. 666-668) synthesized tetrazoloil,5e] thieno[3,2 e]pyrimldlnes and evaluated the anti-inflammatory activity.
A few 5(indan-1'yl) tetrazoles were synthesized and screened for antiinflammatory and related biological activities. 5(indan-1'yl) tetrazole was found to be superior to phenyl butazone in established adjuvant Induced arthritis and yeast induced pyrexia biomodels in rats (Ray S.M. and Lahiri S.C, J. Indian Chem. See, 1990, 67, 324-326.83. Okabayashi T., Kano H. and Makisumi Y., Chem. Pharm. Bull., 1960,8,157).
Tetrazoles (Wazir V., Singh G.B., Singh S., Gupta R. and Kachroo P.L., J. Indian. Chem. Sec, 1991, 68, 305) 1,4-dlhydro-3-pyridyltetrazoles(Kumar P. and Knaus E.E., Drug. Des. Discovery., 1991, 7, 287) Furyltetrazoles (Janda L.,

Voticky Z., Svetlik J., Grimove J. and Maturova E., Coll. Czech. Chem. Commun., 1984, 49, 1505) and 2,5-disubstituted tetrazole (Pande K., Tendon M., Bhalla T.N. and Bharthwal J.P., Indian. J. Chem., 1984, 23B. 1133) showed antiinflammatory activity against carrageenin induced rat paw edema.
5-lmino-1-(2 hydroxy-2-arylethyl)tetrazoles have also been mentioned as antinflammatory, analgesic and hypothermic agents (Mugnaini A., Friz L.P, Provincaili E., RugarIi P., Olivi A., Zefelippo E., Almirante L. and Murmann N., Boll. Chim. Farm., 1966, 105, 596; Chem. Abstr., 1967, 66, 75958). A weak CNS depressant and analgesic activity was observed (Crawley L.S. and Safir S.R., U.S. Patent. 1976, 3,966,756;Chem.Abstr., 1976, 85, 192783. Gebert U., Musil J. and Weber R.O., Ger. Often.1978, 2, 650,231; Chem. Abstr., 1978, 89, 75374) for certain tetrazole analogues.
Martin et al. (Martin .W., Biswanathi D., Thomas Zydowsky M., Daniel Kerkamnn J., John Debernein F., Sand Roserburg H., Kaumi Shiosaki H., Fatima Basha Z. and Andrew Tasker., Abbot. Laboratories, U.S. Pat.1993, 5, 250,548; Chem. Abstr., 1994, 121, 628) synthesized [(tetrazolyl biphenyl) methyl amino]pyridine carboxylate and evaluated their angiotensin receptor antagonist action.
Of thirtyfour tetrazole derivatives synthesised by Cosgrove et al. (Cosgrove C.E. and Laforge R.A., J. Org. Chem., 1956, 21, 197) sixteen produced a considerable drop in blood pressure for at least five min in anaesthesised dogs.
Several 5-dialkyl amino alkyl tetrazoles showed potent alpha anti-adrenergic activity(Hayao S., Havera H.J., Strycker W.G., Leipzig T.J. and Rodriguez R., J, Med. Chem., 1965,10, 400).

Reaction of N-phenylpiperazine with acrylonitrile produces nitrile and conversion of this nitrile to a tetrazole ring via 1,3 diploar addition process by sodium azide under ammonium chloride catalysis produces zolterine an antihypertensive agent (Stryker W.G. and Hayao S., Belgium Patent. 1965, 661, 1390; Chem.Abstr. 1965, 63,18114e).
Gupta et al. (Gupta A.K.S., Bhattacharya T. and Rastogi A., Indian. J. Chem. 1985, 24B. 578) reported the synthesis and in vitro evaluation of 2-[(1-aryl-1 H-tetrazol-5-yl)thio-N-[(arylamino)carbonyl]acetamides as acetylcholinesterase inhibitors. Milcent et al. [Mllcent R., Lebreton L., Mazouz. and Burstein C, FR2631827 Al 1 Dec 1989; Chem. Abstr. 113,191368k] reported 2,5-disubstituted tetrazoles as type B monoamine oxidase (MAO) inhibitors.
5-(3-p-cyanophenoxy-2 hydroxy-1-propoxy)-2-(1 H-tetrazol-5-yl) chromone sodium was tested for anti allergic activity (Francis D.I., Spicer J.W., Taylor W.A. and Warren B.T., Antiallergic Chromones, Fifth International Symposium on Medicinal Chemistry, Paris, 1976,19-22).
Several 3-(terazol-5yl) chromones have been reported to be active as antiallergic agents. Among these the derivative with substituents at 6 and 8 positions and the benzo analogues were found to be very active as anti allergic agents (Nohara A., Tetrahedron letters., 1974,1187).
Several tetrazolium nitrogen mustards have been prepared and evaluated for antineoplastic activity (Tsov K.C. and Su H.C.F., J. Med. Chem., 1963, 6, 693).

6-chloro tetrazolo [1,5-b]pyridazine was reported to inhibit the growth of He La cells and also showed activity against experimental tumor(Bary V.C., Conalty M.C., O'sullivan J.P. and Twomey., Pro. 9* Int. Congr. Chemother., 1977, 8, 103; Chem. Abstr., 1977, 87, 23287).
Tetrazole analogues of potent non-steriodal oestrogens have been prepared (Crenshaw R.R., Luke G.M. and Bialy G., J. Med. Chem., 1972, 15, 1179) by
replacing the respective carboxyl group with a tetrazole moiety with the hope of dissociating antifertility and oestrogenic activities but the compounds were inactive.
The tetrazole analogues of progesterone and testosterone, namely, 7 a-aza-B-homo-4-pregneno [7a,7d]tetrazole-3,20-dione and oxo-7a-aza-B-homo-4a-androsteno [7a,7d]tetrazol-17-pyl acetate have been prepared and evaluated for hormonal activity (Singh H., Bhutani K.K., Malhotra R.K. and Paul D., Experlentia, 1978, 34, 557. Singh H., Bhutani K.K., IVIalhotra R.K. and Paul D., J. Chem. See, 1979,1, 3166).
A tetrazolyl sulphonamide, 5-(4-chloro-5-sulphamoyl-2-thienylamino phenyl) tetrazole was synthesised and evaluated for diuretic acitivity (Popelak A., Lerch A., Stach K., Rosesch E. and Hardebeck K., Ger. Offen.,1975, 2, 423, 550, 90740. Kuhn R., Hardebeck K., Heinemann H. and Osmers K., Ger. Offen., 1975, 2, 423 550; Chem. Abstr. 1976, 84, 49849).

The main objective of the present invention is to provide novel 5[(p-10 phenothiazinyl) ethyl] 1,2,3,4 tetrazoles of the following general formula 4 (Figure 1) useful as antimicrobial, analgesic and anticonvulsant.
The another objective of the present invention is to provide a process for the preparation of novel 5-[(p-10 phenothiazinyl) ethyl]-1-(acyl), 2, 3, 4 - tetrazoles.
Yet another objective of the present invention is to provide compounds useful in the treatment of microbial infections, convulsions and as analgesic.
Accordingly, the present invention provide a process for the preparation of novel 5-[(p-10 phenothiazinyl) ethyl]-1-(acyl), 2, 3, 4-tetrazoles of the general formula (Figure 1), useful as antimicrobial, analgesic and anticonvulsant, comprises the

In an embodiment of the present invention the phenothiazines used are selected from phenothiazine 2-chlorophenothiazine, 2-methylphenothiazine, 2-ethylphenothiazlne and 2-trifuormethylphenothiazine.
In another embodiment of the present invention the Triton B was selected as catalyst for cyanoethylation.
In yet another embodiment of the present invention dimethyl formamide, ammonium chloride and sodium azide was selected.
In yet another embodiment of the present invention the acid chloride used are selected from aliphatic acid, aromatic acid and aryl acyl chlorides like acetyl chloride, propionyl chloride, benzoyl chloride, p-chlorobenzoyl chloride, o-nltrobenzoyl chloride, p-nitrobenzoyl chloride, p-hydroxy benzoyl chloride, p-aminobenzoyl chloride, p-methylbenzoyl chloride, p-methoxybenzoyl chloride, phenyl acetyl chloride and p-toluene benzene sulphonyl chloride.
In a further embodiment of the present invention the solvents employed for extraction of the compound from the reaction mixture are selected from the group consisting of chloroform, dichloromethane and ethyl acetate.
In a further embodiment the recovery and purification of the compound produced is effected by chromatography using eluant selected from the group consisting of hexane, chloroform, ethyl acetate, toluene, methanolic or ethanolic toluene, benzene, methanolic or ethanolic benzene and a mixture thereof.
The compounds were also tested for their antimicrobial, analgesic and anticonvulsant activity.
The process of the present invention is already explained by the reaction scheme depicted in figure 1.

The representative compounds of the formula 4 prepared by the process of the invention are as follows: Compound 1
1-acetyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 2
1-propionyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 3
1-benzoyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 4
1-p-chloro benzoyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 5
1-o-nitro benzoyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 6
1-p-nitro benzoyl-5-[(P-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 7
1-p-hydroxy benzoyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 8
1-p-amino benzoyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 9
1-p-methyl benzoyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 10
1-p-methoxy benzoyl-5-[(P-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole Compound 11 1-phenylacetyl -5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole

Compound 12
1-Toluene-p-sulphonyl-5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole
The advantages of the present invention is that it provides a new class of compounds which are antimicrobial, analgesic and anticonvulsant and are much simpler than existing fluconazole, the standard drug. The starting materials of the compounds of the present invention are cheap and easily available. The process described here is simple, economically feasible and eco-friendly.
The invention is illustrated by the following examples, which is no way represent as limitation thereof.
Example 1 10-Phenothiazinvl propionitrile
Phenothiazine (9.95 g, 0.05 mole) was mixed with 12.5 ml of acrylonitrile in a 100 ml round bottomed flask and cooled in ice bath. A crystal of resorcinol was added to prevent polymerisation. Triton B (2 ml) was added dropwise with shaking. A vigorous reaction was set in. It was allowed to subside and then the contents of the flask were refluxed on a steam bath for 2 h. The solution was cooled, extracted with ethylene dichloride and dried over anhydrous sodium sulphate. The dried nitrile was recrystallised (yleld 82 %) from ethanol, melted at 159-160°C.
Example 2 5-r(B-10- Phenothiazinyl) ethvl 11.2.3.4 tetrazole
A mixture of phenothiazinyl propionitrile (3.3 g, 0.01 mole), sodium azide (1 g, 0.01 mole) dimethylformamide (10 ml) and ammonium chloride (5.3 g, 0.1 mole) were taken in a 100 ml round bottomed flask. The contents were heated in an oil bath for 7 h at 125°C. The solvent was removed at reduced pressure. The reaction mixture was dissolved in 100 ml of distilled water and carefully acidified with

concentrated hydrochloric acid to pH2. The solution was cooled to 5°C in ice bath. The product was rennoved by filteration, washed with several portions of water and dried. The crude product was recrystallized{yleld 77 %) from aqueous methanol, melted at 148-149°C.
Example 3 1-Acetyl-5-r(B-10 phenothiazinvh ethvIM .2.3.4 tetrazole
Acetic anhydride was used for the synthesis of N-acetyl derivative of tetrazole since acetyl chloride is not satisfactory as it forms equivalent quantity of tetrazole hydrochloride. Refluxed gently the 5 - [(P-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1 g, 0.0025 mole) under a short air condenser with acetic anhydride (3 g, 0.03 mole) for 15 minutes. Cooled the reaction mixture and poured it into 20 ml of cold water. Boiled to decompose the excess acetic anhydride. Cooled and filtered the insoluble acetyl derivative and washed with little cold water. The dried compound was recrystallised (yleld 88 %) from dilute ethanol, melted at 134-135°C.
Example 4 1-Propionvl-5-r(B-10 phenothiazinvn ethyl] .2.3.4 tetrazole
Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and propionyl chloride (4.2 g, 0.045 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of propionyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any propionic acid, which may be present. The dried compound was recrystallised (yleld 54 %) from dilute ethanol, melted at 125-126°C.

Example 5 1-Benzovl-5-r(B-10 phenothiazinvn ethvlM.2.3.4 tetrazole
Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and benzoyl chloride (4.2 g, 0.03 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of benzoyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any benzoic acid, which may be present. The dried compound was recrystallised (yleld 59 %) from dilute ethanol, melted at 106-107°C.
Example 6 1-p-Chloro benzovl-5-r(B-10 phenothiazinyl) ethvIM .2.3.4 tetrazole
Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and p-chlorobenzoyl chloride (3.5 g, 0.02 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of p-chlorobenzoyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any p-chlorobenzoic acid, which may be present. The dried compound was recrystallised(yleld 67 %) from dilute ethanol, melted at 168-169°C.
Example 7 1-o-Nitro benzovl-5-r(B-10 phenothiazinyl) ethyll-l.2.3.4 tetrazole
Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and o-nitrobenzoyl chloride (3.71 g, 0.02 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube.

When the odour of o-nitrobenzoyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any o-nitrobenzoic acid which may be present. The dried compound was recrystallised(yleld 71 %) from dilute ethanol, melted at 109-110°C.
Example 8 1-p-Nitro ben2ovl-5-r(B-10 phenothiazinvl) ethvIM.2.3.4 tetrazole Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and p-nitrobenzoyl chloride (3.71 g, 0.02 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of p-nitrobenzoyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any p-nitrobenzoic acid, which may be present. The dried compound was recrystallised (yleld 69 %) from dilute ethanol, melted at 171-172°C.
Example 9 1-p-hvdroxvbenzovl-5-r(B-10 phenothlazlnvn ethyl] .2.3.4 tetrazole
Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and p-hydroxybenzoyl chloride (3.13 g, 0.02 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of p-hydroxybenzoyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any p-hydroxybenzoic acid, which may be present. The dried compound was recrystallised (62 %) from dilute ethanol, has melting range >210°C.

Example 10 1-p-Aminobenzovl-5-r(B-10 phenothiazinvl) ethvIM.2.3.4 tetrazole
Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and p-aminobenzoyl chloride (3.11 g, 0.02 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of p-aminobenzoyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any p-aminobenzoic acid, which may be present. The dried compound was recrystallised(yleld 62 %) from dilute ethanol, has melting range >210°C.
Example 11 1-/o-Methvlbenzovl-5-r(B-10 Phenothiazinyl) ethvlM.2.3.4 tetrazole
Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and p-methylbenzoyl chloride (3.1 g, 0.02 mole) was added to it. Shaken the mixture vigorously In a stoppered test tube. When the odour of p-methylbenzoyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any p-methylbenzoic acid, which may be present. The dried compound was recrystallised(yleld 64 %) from dilute ethanol, melted at 121-122°C.

Example 12 1-p-Methoxvbenzovl-5-r(3-10 phenothiazinvl) ethvn-1.2.3.4 tetrazole
Dissolved 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and p-methoybenzoyl chloride (3.1 g, 0.02 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of p-methoxybenzoyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any p-methoxybenzoic acid, which may be present. The dried compound was recrystallised(yleld 68 %) from dilute ethanol, melted at 158-159°C.
Example 13 1-Phenvlacetvl-5-r(B-10 phenothiazinvl) ethvn-1.2.3.4 tetrazole
Dissolved 5-[((3-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole( 1.99 g, 0.05 mole) in 10 ml of 10 % sodium bicarbonate solution and phenylacetyl chloride (3.1 g, 0.02 mole) was added to it. Shaken the mixture vigorously in a stoppered test tube. When the odour of phenylacetyl chloride has disappeared, the contents were acidified with dilute hydrochloric acid to Congo red and filtered. Extracted the solid with a little cold ether to remove any phenylacetic acid, which may be present. The dried compound was recrystallised(yleld 64 %) from dilute ethanol, melted at 127-128°C.
Example 14 1-Toluene-p-sulphonvl-5-r(B-10 phenothiazinvl) ethvn-1.2.3.4 tetrazole Treated 5-[(p-10 phenothiazinyl) ethyl]-1,2,3,4 tetrazole (1 g, 0.025 mole) with 20 ml of 10 % sodium bicarbonate solution and toluene-p-sulphonyl chloride (4.75 g, 0.025

mole) was added in small portions with constant shaking. The contents were shaken vigorously in a stoppered test tube to remove the excess of acid chloride. The contents were acidified with dilute hydrochloric acid and filtered. The dried compound was recrystallised (yleld 60 %) from dilute ethanol, melted at 97-98°C.
Example 15 Evaluation of Antibacterial Activity
The plates containing nutrient agar were seeded with different test bacteria aseptically with the help of sterile swab. Well of 6 mm in diameter were made with sterile borer. Each well were added with 50 |al of the solution of synthesised compounds using micropipette. They were allowed to diffuse for about 1 h. One well for each test microorganism was served as solvent control. The plates were then incubated at 37°C for 24 h and the diameter of zone inhibition was measured in four directions and the average was taken into account and compared with standard antibacterial drug ciprofloxacin. (Table-1) Evaluation of Antifungal Activity
The plates containing sabouraud dextrose agar were seeded with Aspergillus niger NCIM 1054 and Candida albicans NCIM 3102 aseptically with the help of sterile swab. Well of 6 mm in diameter were made with sterile borer. Each well were added with 50 il of the solution of synthesised compounds using micropipette. They were allowed to diffuse for about 1 h. One well for each test microorganism was served as solvent control. The plates were then incubated at 28°C for 48 h and the diameter of zone inhibition was measured in four directions and the average was taken into account and compared with standard antifungal drug Fluconazole. (Table-1)

Example 16 Evaluation of Analgesic activity bv a.Acetic acid induced writhing method
The method suggested by Witkin et al. was adopted for the study. Swiss strain albino mice of either sex weighing 25-30 g were used for this study. The animals were then divided into 28 groups of 10 mice each. Tween 80 suspensions (10 %v/v) of the test compounds were administered intraperitoneaily in dose of 25 mg/kg(bw). The control group of animals was given only 10 %v/v Tween 80(0.5 ml) suspension. One group of animals was given with Nimesulide as standard, intraperitoneaily in a dose of 10 mg/kg(bw). After 20 minutes of the administration of the test compounds, all the groups of mice were given with the writhing agent 3 % v/v aqueous acetic acid in a dose of 2 ml/kg(bw), intrperitoneally. Writhing is defined as stretch, torsion to one side, abdominal contractions, trunk twist respose and extension of hind limbs. The writhings produced in these animals were counted for 15 minutes and the number of writhings produced in treated groups was compared with those in the control group. (Table-2) The results were analysed statistically by student't' test.

Dose: 25 mg/kg for all the test compounds and 10 mg/kg for Nimesullde Comparison with Control *Highly significant P
b.Hot Plate Method
The method of Eddy and Leimbach, with modification by Aparicio was followed. Swiss strain albino mice of either sex weighing 25-30 g were used for the study and they were deprived of solid food and water for 24 h, prior to the administration of compounds. The animals were selected based on the reaction time and for this, they were placed on a hot plate at 55 ± 0.5°C. Animals showed the reaction time > 10 sec was rejected. When a mouse is placed on a plate at 55 ± 0.5°C, it takes 4-5 seconds, to lick its hind paws or tries to jump out in an attempt to escape the heat. The time observed was called normal reaction time. After selection, the animals were divided into 28 groups of 6 mice each. Tween 80 suspensions (10 %v/v)of the test compounds were administered intraperitoneally in dose of 25 mg/kg(bw). The control group of animals was given only 10 %v/v Tween 80(0.5 ml) suspension. One group of animals was given with Morphine sulphate as standard, intraperitoneally in a dose of 5 mg/kg (bw). The pain threshold was measured by using Hot Plate for fifteen minutes, thirty minutes after the administration of the drug and thereafter at hourly intervals for two hours. (Table-3)

Dose; 25 mg/kg for all the test compounds and 5 mg/kg for Morphine sulphate Comparison with Control *Highly significant P
Example 17 Evaluation of Anticonvulsant Activity by a.Maximal Electroshock Induced Convulsion method
Goodman et al. method was adopted for studylng anticonvulsant activity. Swiss strain albino rat of either sex (150 - 210 g) were given supramaximal electroshock through ear electrodes of 150 mA for 0.2 sec by a Techno(Lucknow) electroconvulsiometer. Animals that showed positive hind limb tonic extensor response were selected and they were divided into 28 groups of six rats each. One group was treated with standard drug phenytoin(25 mg/kg) and the other control group was treated only with 10 %v/v Tween 80. Then the synthesized compounds 1-26 suspended in 10 %v/v Tween 80 were administered intraperitoneally in a dose of 25 mg/kg one hour before seizure induction. Onset times(sec) for myoclonic jerks, clonus, extensor and stupor phases and death were noted. Percentage mortality was also recorded. The protective index was observed as the abolision or reduction of the hind limb tonic extension component of the seizure. (Table-4)

Dose: 25 mg/kg for all the test compounds and phenytoin
Comparison with Control *Highly significant P *** insignificant P
b.Strychnine Induced Convulsion method
Chen et al. method was followed to evaluate the anticonvulsant activity for the synthesised compounds. Swiss albino mice of either sex weighing 25-30 g were divided into 15 groups with 6 mice in each group. Tween 80 suspensions(10 % v/v) of the synthesised compounds were administered intraperitoneally in a dose 25 mg/kg prior to the administration of strychnine( 2mg/kg, b.w). The control group of animals was given only with 10 %v/v Tween 80 suspension(0.5 ml). The percentage mortality was noted after 15 min of strychnine administration for each group. (Table-

I Claim
1 .A process for the preparation of novel 5-[(β-10 phenothiazinyl) ethyl]-1-(acyl),2,3, 4-tetrazoles of the general fornnula (Figure 1), useful as antimicrobial, analgesic and anticonvulsant, comprises the following steps.

2.A process as claimed in claim I wherein the phenothiazines used are selected
from phenothiazine or substituted phenothiazine 3.A process as claimed in claim I wherein the catalyst for cyanoethylation is
selected as Triton B.
4. A process as claimed in claim I wherein dimethyl formamide, ammonium chloride
and sodium azide are selected.
5. A process for the preparation of novel 5-[(p-10 phenothiazinyl)ethyl]-1-acyl,2,3,4-
tetrazoles substantially as herein described with reference to examples

Documents:

0403-mas-2002 abstract-duplicate.pdf

0403-mas-2002 abstract.pdf

0403-mas-2002 claims-duplicate.pdf

0403-mas-2002 claims.pdf

0403-mas-2002 correspondence-others.pdf

0403-mas-2002 description (complete)-duplicate.pdf

0403-mas-2002 description (complete).pdf

« Previous Patent

Next Patent »

Patent Number

202803

Indian Patent Application Number

403/MAS/2002

PG Journal Number

30/2009

Publication Date

24-Jul-2009

Grant Date

Date of Filing

24-May-2002

Name of Patentee

A. RAJASEKARAN

Applicant Address

29 E/3 CHENDRIKULAM STREET, MAYILADUTHURAI - 3

Inventors:

#	Inventor's Name	Inventor's Address
1	A. RAJASEKARAN	29 E/3 CHENDRIKULAM STREET, MAYILADUTHURAI - 3

PCT International Classification Number

A61K31/41

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA