|Title of Invention||
"PROCESS FOR PREPARING COMPOUNDS OF FORMULA (I)"
|Abstract||Process for preparing compounds of the formula (I), in which R1 is C1-C12-alkyl, C1-C12-fluoroalkyl, C1-C12-alkoxy, C1-C12-fluoroalkoxy, cyano, nitro, iodine, bromine, chlorine or fluorine and n is 0, 1,2 or 3 wherein compounds of the formula (II) where R1 and n have the same meaning as described above are react with thiophosgene or other thiocarbamic acid derivatives.|
|Full Text||The invention relates to difluorobenzo-l,3-dioxoles, to a process for their preparation, and to their use for preparing medicaments and crop protection agents.
Difluorobenzo-l,3-dioxoles are valuable building blocks in active agrochemical and pharmaceutical ingredients; see also WO 02/81453, in particular example 321. In order to be able to introduce the difluorobenzo-l,3-dioxole building block into the active ingredient molecule, 5-bromodifluorobenzo-l,3-dioxole is subjected to a palladium-catalysed transformation which is expensive from an industrial viewpoint. There is therefore a need to provide difludrobenzo-l,3-dioxoles which can be incorporated in a simple manner into such active ingredient molecules via a functionality intrinsic to them and which can be prepared in a simple and efficient process.
Compounds of the formula (I) have now been found
R1 is C1-C12-alkyl, C1-C12-fluoroalkyl, C1-C12-alkoxy, C1-C12-fluoroalkoxy, cyano, nitro, iodine, bromine, chlorine or fluorine and
n is 0,1,2 or 3.
The compounds of the formula (I) can be converted in a simple manner known from WO 02/81453 to the thioxoimidazolinones described there.
A process has also been found for preparing compounds of the formula (I), which is characterized in that compounds of the formula (II)
in which R1 and n are each as defined above are converted in a manner known in principle to the corresponding isothiocyanates.
Preferred processes include:
The reaction with thiophosgene or other thiocarbamic acid derivatives, in particular chlorothiocarbonylimidazole or thiocarbonylbisimidazole
the reaction with carbon disulphide in the presence of alkali metal base and subsequently the reaction either with an oxidizing agent or with phosgene or oxalyl chloride
the preparation of corresponding isonitriles or isocyanide dihalides and subsequent sulphurization.
The reaction with thiophosgene is particularly preferred, and the reaction is advantageously effected in aqueous-acidic medium.
The processes mentioned are sufficiently well known in terms of principle from the literature. The compounds of the formula (II) used as starting compounds are either known from the literature or can be prepared analogously to the literature. It is to be regarded as particularly surprising that the difluorobenzodioxole function which is known to be labile and thermally sensitive and sensitive towards halogen exchange is not attacked to a significant extent by the reaction.
The scope of the invention embraces all radical definitions, parameters and illusfrations above and listed hereinbelow, in general or within areas of preference, in any combination with one another, i.e. also between the particular areas and areas of preference.
Alkyl and alkoxy are each independently a straight-chain, cyclic, branched or unbranched alkyl and alkoxy radical respectively, and the radicals mentioned may optionally be further substituted by C1-C4-alkoxy radicals.
C1-C12-Alkyl is, for example and with preference, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, neopentyl, 1-ethylpropyl, cyclohexyl, cyclopentyl, n-hexyl, n-heptyl, n-octyl, n-decyl and n-dodecyl.
C1-C12-Alkoxy is, for example and with preference, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentoxy, cyclohexoxy, cyclopentoxy, n-hexoxy, n-heptoxy, n-octoxy, n-decoxy and n-dodecoxy
Fluoroalkyl and fluoroalkoxy are in each case independently a straight-chain, cyclic, branched or unbranched alkyl radical and alkoxy radical respectively, each of which is substituted singly, multiply or fully by fluorine atoms.
For example, C1-C12-fluoroalkyl is trifluoromethyl, 2,2,2-trifluoroethyl, pentafluoroethyl, nonafluorobutyl, heptafluoroisopropyl, perfluorooctyl and perfluorododecyl.
For example, C1-C12-fluoroalkoxy is trifluoromethoxy, 2,2,2-trifluoroethoxy, pentafluoroethoxy, nonafluorobutoxy, heptafluoroisopropoxy, perfluorooctoxy and perfluorododecoxy.
The preferred substitution patterns for the compounds of the formulae (I) and (II) are defined hereinbelow:
R' is more preferably methyl, ethyl, n-propyl, chlorine, fluorine and bromine, most preferably chlorine or fluorine.
n is preferably 0,1 or 2, more preferably 0 or 1 and most preferably 0.
A particularly preferred compound of the formula (I) is 5-isothiocyanato-2,2-difluorobenzo-1,3-dioxole.
A particularly preferred compoimd of the formula (II) is 5-amino-2,2-difluorobenzo-l,3-dioxole.
The inventive compounds of the formula (I) are suitable in particular for preparing medicaments, agrochemicals or intermediates thereof. Compounds of the formula (I) may be used preferably for the preparation of thioxoimidazolinones, in particular for those such as are described in WO 02/81453.
Preparation of 5-isothiocyanato-2,2-difluorobenzo[l,3]-dioxole:
34.6 g of 5-amino-2,2-difluorobenzodioxole are added dropwise to a solution of 90 ml of cone, hydrochloric acid in 350 ml of water. The mixture is stirred for a further 30 minutes and then 27 g of thiophosgene are metered in rapidly. The mixture is stirred at the given temperature for a further 3 hours, the almost colourless suspension is admixed with 150 ml of dichloromethane and the dichloromethane is removed. The crude product is distilled at 45 mbar. 28 g (= 89% of theory) are obtained as a colourless to yellowish liquid.
Boiling point: 136°C/45 mbar.
1H NMR (400 MHz, CDCl6): 6.96 (m, 2 H), 7.02 (m, 1 H)
1. Process for preparing compounds of the formula (I),
R1 is C1-C12-alkyl, C1-C12-fIuoroalkyl, C1-C12-alkoxy, C1-C12-fluoroalkoxy, cyano, nitro,
iodine, bromine, chlorine or fluorine and
n is 0, 1,2 or 3
wherein compounds of the formula (II)
where R1 and n have the same meaning as described above are react with thiophosgene or other thiocarbamic acid derivatives.
2. Process as claimed in claim 1, wherein the reaction with thiosphosgene is carried out in an
3. Process as claimed in claim 1 wherein compounds of the formula (II) are react with chlorothiocarbonylimidazole or thiocarbonylbisimidazole as thiocarbamic acid derivatives.
|Indian Patent Application Number||1180/DEL/2005|
|PG Journal Number||20/2013|
|Date of Filing||10-May-2005|
|Name of Patentee||LANXESS DEUTSCHLAND GMBH|
|Applicant Address||D-51369 LEVERKUSEN, GERMANY.|
|PCT International Classification Number||C07D|
|PCT International Application Number||N/A|
|PCT International Filing date|