Title of Invention	"PROCESS FOR THE PREPARATION OF ALKYL N-ALKYLANTHRANILATE"
Abstract	There is disclosed a process for the preparation of alkyl ester of N-alkylanthranilic acid represented by Formula 1 wherein R1 and R2 contain from 1 to 8 carbon atoms, are alkyl, substituted alkyl, or alkyl containing a saturated ring, said process comprising the steps of: reacting 2H-3, l-benzoxazine-2. 4(lH)-dione (isatoic anhydride) in a polar aprotic organic solvent, such as herein described, as medium, with a solid metal hydroxide or basic metal oxide, such as herein described; adding an alkylating agent, such as herein described; reacting the intermediate with an alkyl alcohol, such as herein described; and isolating the product according to Formula 1 by adding water to the reaction mixture and extracting with a non water miscible organic solvent, such as herein described.

Title of Invention

"PROCESS FOR THE PREPARATION OF ALKYL N-ALKYLANTHRANILATE"

Abstract

There is disclosed a process for the preparation of alkyl ester of N-alkylanthranilic acid represented by Formula 1 wherein R1 and R2 contain from 1 to 8 carbon atoms, are alkyl, substituted alkyl, or alkyl containing a saturated ring, said process comprising the steps of: reacting 2H-3, l-benzoxazine-2. 4(lH)-dione (isatoic anhydride) in a polar aprotic organic solvent, such as herein described, as medium, with a solid metal hydroxide or basic metal oxide, such as herein described; adding an alkylating agent, such as herein described; reacting the intermediate with an alkyl alcohol, such as herein described; and isolating the product according to Formula 1 by adding water to the reaction mixture and extracting with a non water miscible organic solvent, such as herein described.

Full Text	Process for the preparation of alkyl N-alkylanthranilate Technical field of the invention The invention relates to a process for the preparation of alkyl N-alkylanthranilate of the Formula 1. \ Wherein R1 and R2 contain from 1 to 8 carbon atoms, are alkyl, substituted alkyl, or alkyl containing a saturated ring. More particularly it is concerned with the preparation of MethylN-methylanthranilate, Formula I, R1 = R2 = Me Background of the invention Methyl N-methylanthranilate (DMA) is a valuable compound used in the flavouring and fragrance industry and is also reported to be a bird, repellent described in patent US 2,967,128. Several methods are known for the preparation of DMA. A classical route is N-methyiation of methyl anthranilate with a methylating agent as dimethyl sulfate or methyl iodide, cited in patent DE 3936229. To avoid dimethylation, reductive methylation with formaldehyde and hydrogen has been described in patent US 4633009. Reaction scheme I. 1 To prepare methyl anthranilate, 2H-3,l-benzoxazine-2,4 (lH)-dione (isatoic anhydride) is reacted under alkaline conditions with methano] as disclosed in patent IN 146359, Reaction scheme 2. As disclosed by Staiger, J. Org. Chem. (1959), 24,1214-19 , N-methylisatoic anhydride reacts with methanol under alkaline conditions to produce Methyl N-raethylanthranilate. Hardtmann, J. Heterocycl. Chem. (1975), 12 (3), 565-72 prepares N-substituted isatoic anhydride by reacting the N-sodium salt of isatoic anhydride, prepared from sodium hydride, with alkyi halides. The N-benzyl derivative of isatoic anhydride is prepared using potassium carbonate and benzyl chloride. Disclosure of invention It is an object of this invention to provide a fecile process for the preparation of N-alkyl alkylanthranilates, specially N-methyl meihylaiithranilate, in commercial quantities, good yield and high purity. An obvious route would be a one pot synthesis starting with the ready available isatoic anhydride, N-alkylation and final reaction with an alcohol to furnish the title product. Accordingly, the present invention provides a process for the preparation of alkyi esters of N-alkylanthranilic acid represented by Formula 1 wherein R1 and R2 contain from 1 to 8 carbon atoms, are alkyl, substituted alkyl, or alkyl containing a saturated ring, said process comprising the steps of. 2 reacting 2H-3, l-benzoxazine-2,4 (lH)-dione (isatoic anhydride) in a polar aprotic organic solvent, such as herein described, as medium, with a solid metal hydroxide or basic metal oxide, such as herein described; adding an alkylating agent, such as herein described; reacting the intermediate with an alkyl alcohol, such as herein described; and isolating the product according to Formula 1 by adding water to the reaction mixture and extracting with a non water miscible organic solvent, such as herein described. Preferably, the polar aprotic solvent is selected from the group comprising of an aliphatic carboxamide, an aliphatic nitrile, an aliphatic ether, an aliphatic sulphoxide, or hexaalkyl phosphoric triamide. More preferably, the polar aprotic solvent is dimethyl formamide or 1 -methyl-2-pyrrolidinone. Preferably, the solid metal hydroxide or basic metal oxide has the metal part selected from the group comprising of Li, Na, K, Ca and Ba. More preferably, the metal hydroxide is sodium hydr6xide or potassium hydroxide. Preferably, the alkylating agent is an alkyl halide, wherein the alkyl group contains from 1 to 8 V carbon atoms, are alkyl substituted alkyl or alkyl containing a saturated ring and the halide is represented by Cl, Br or I. More preferably, the alkylating agent is a dialkyl ester of sulfuric acid (dialkyl sulfate) wherein the alkyl group contains from 1 to 8 carbon atoms, are alkyl, substituted alkyl or alkyl containing a saturated ring.Most preferably the alkylating agent is dimethyl sulfate Preferably, the alkyl alcohol is a primary, secondary or tertiary alkyl alcohol or an alcohol containing a cyclic aliphatic structure, with up to a maximum of 8 carbon atoms, for the final ring opening process. More preferably, the alkyl alcohol is methanol. Preferably, the non water miscible organic solvent is a C 5-10 linear, branched, or cyclic alkane or an ether for isolating the final product by extraction. More preferably, the non water miscible organic solvent is hexane. Surprisingly it turned out that a solid metal hydroxide or basic metal oxide, preferable sodium or pottasium hydroxide in a suitable polar solvent such as dimethylforamide or l-methyl-2-pyrrolidinone could form the N-metal salt with isatoic anhydride. Depending on solvent, concentration or temperature the metal salt would separate to form a dispersion. One would anticipate that water formed during the salt formation immediately would react with isatoic anhydride, forming anthranilic acid. Surprisingly this was not the case. Trials using metal alkoxides resulted in that the alkohols formed, reacted with isatoic anhydride to form alkyl esters of anthranilic acid. N-methylation could be achieved by adding an alkylation agent. Preferably methyl iodide or dimethyl sulfate in a molar ratio, relative to isatoic anhydride, from 1 to 5, preferably 1.5, at a temperature from 10 - 40 C. In the case of a methylating agent, the intermediate N-methylisatoic anhydride could be isolated by filtration as a colourless crystalline compound by adding 2 parts of water to the reaction mixture. Identification was established by compare HPLC chromatograms with authentic material (supplied by Aldrich). After N-alkylation of isatoic anhydride has been performed 1 to 50 mole parts of an alkyl allcohol, relative to isatoic anhydride, is added to the reaction mixture at a temperature between 10 and 40°C. The temperature is elevated to distil excess of alkyl alcohol off. Leaving 50% to 0% of the alcohol in the reaction mixture. Preferably 10%. By alcohol addition under alkaline conditions, N-alkylisatoic anhydride, is ring opened, forming alkyl N-alkylanthranilate with subsequent elimination of carbon dioxide. Alkyl N-alkylanthranilate is isolated by adding 1 to 5 parts of water to the reaction mixture, and extract the mixture with a non water miscible organic solvent. The extraction solvent could be an alicyclic or cyclic hydrocarbon, halogenated derivatives hereof, aliphatic ethers or esters. Preferably hexane. The organic phase is washed with water, and evaporated in vacuo, leaving alkyl N-allcylanthranilate as an oil with purity about 97% and yield about 85%. 3 Examples Products were analysed by gas chromatography. Using SRI Instruments model 310 equipped with column Restek, MXT-5, 15 m, 0.54 ID, FID detector and temperature gradient 90 - 200°C, 10° /min. Peaks were identified by running authentic samples. Example 1 Methyl N-methvlantfrranilate To dry Dimethylforamide (DMF), 300 mL, covered with nitrogene, solid pulverised sodium hydroxide, 97% assay, 14.12 g, 0.3424 moles, is added. Isatoic anhydride, 96% assay, 40.00 g, 0.2354 moles, is dissolved in dry DMF, 100 mL. To the stirred suspension of sodium hydroxide covered with nitrogen, the solution of isatoic anhydride is added at 30°C over 30 min. and the mixture is stirred for a further 15 min. Dimethyl sulfate, 32.88 g, 0.2588 moles is added drop wise with stirring over 20 min., allowing temperature to rise to max 45°C. The solution is stirred at ambient temperature for a further 30 min. Methanol, 50 mL, is added, the mixture is stirred for 15 min at 25°C. Temperature is elevated to distil methanol off. When temperature reaches 100 C, the mixture is cooled to 20°C and water, 800 mL is added. Ammonia solution, 2 mL, 25 w/w% is added to destroy excess dimethyl sulfate. The cloudy mixture is extracted with hexane, 200 mL. The hexane phase is separated, washed with water and distilled on a rotary evaporator at 15 mm Hg and 100°C leaving crude Methyl N-methylanthranilate, 33.80 g, with a composition, by GC, of 2.1% Methyl anthranilate and 97.5% Methyl N-methylanthranilate, corresponding to a yield of the theoretical of 85%. Crude Methyl N-methylanthranilate, 33,80 g, is distilled through a 30 cm Vigreux column at 130 - 131°C at 15 mm Hg, giving 28.10 g Methyl N-methylanthranilate with a composition, by GC, of 1.5% Methyl anthranilate and 98.5% Methyl N-methylanthranilate. 4 Example 2 To dry Dimethylforamide (DMF), 75 mL, covered with nitrogene, solid pulverised potassium hydroxyde, 85% assay with 15% water, 5.80 g, 0.0879 moles, is added. Isatoic anhydride, 96% purity, 10.00 g, 0.0588 moles, is dissolved in dry DMF, 35 mL. To the stirred suspension of potassium hydroxide covered with nitrogen, the solution of isatoic anhydride is added at 30°C over 30 min. and the mixture is stirred for a further 15 min. Methyl iodide, 12.50 g, 0.0883 moles is added drop wise with stirring over 20 min., allowing temperature to rise to max 40°C. The solution is stirred at ambient temperature for a further 30 min. Methanol, 50 mL, is added, the mixture is stirred for 15 min at 25°C. Temperature is risen so methanol is distilled off. When temperature reaches 100 C, the mixture is cooled to 20°C and water, 200 mL is added, and the mixture is extracted with 2 times hexane. The combined hexane phases are washed with water and distilled on a rotary evaporator at 15 mm Hg and 100°C leaving crude Methyl N-methylanthranilate, 8.10 g, with a composition, by GC, of 4.4% Methyl anthranilate and 95.3% Methyl N-methylanthranilate, corresponding to a yield of the theoretical of 80%. 1: Aprocess for the preparation of alkyl esters of N-alkylanthranilic acid represented by Formula 1 wherein R1 and R2 contain from I to 8 carbon atoms, are alkyl, substituted alkyl, or alkyl containing a saturaieanng, said'process comprising the steps of: reacting 2H-3, l-benzoxazine-2,4 (lH)-dione (isatoic anhydride) in a polar aprotic organic solvent, such as herein described, as medium, with a solid metal hydroxide or basic metal oxide, such as herein described; adding an alkylating agent, such as herein described; reacting the intermediate with an alkyl alcohol, such as herein described; and isolating the product according to Formula 1 by adding water to the reaction mixture and extracting with a non water miscible organic solvent, such as herein described. 2.A process as claimed in Claim 1 wherein R1and R2 are both methyl. 3 .A process as claimed in Claim 1, wherein the polar, aprotic solvent is selected from the group comprising of an aliphatic carboxamide, an aliphatic nitrile, an aliphatic ether, an aliphatic sulphoxide or hexaalkylphosphoric triamide. 4. A process as claimed in Claim 1, wherein the polar, aprotic solvent is dimethylformamide or 1 -methyl-2-pyrrolidinone. 5.A process as claimed in Claiml, wherein the solid base is a metal hydroxide and the metal part is selected from the group comprising of Li, Na, K, Ca and Ba. 6.A process as claimed in Claiml, wherein the metal hydroxide is sodium hydroxide or potassium hydroxide. 7. A process as claimed in Claiml, wherein the solid base is a metal oxide and the metal part is selected from the group comprising of Li, Na, K, Ca and Ba. 8.A process as claimed in Claim 1, wherein the, alkylating agent is an alkyl halide and the alkyl group contains from 1 to 8 carbon atoms, are alkyl, substituted alkyl, or alkyl containing a saturated ring, and the"halide"part is selected from the group comprising of Cl, Br and I. 9.A process as claimed in Claim 1, wherein the alkylating agent is a dialkyl ester of sulfuric acid (dialkyl sulfate), and the alkyl group contains from 1 to 8 carbon atoms, are alkyl, substituted alkyl or alkyl containing a saturated ring, 10.A process as claimed in Claim 1, wherein the alkylating agent is dimethyl sulfate. 11.A process as claimed in Claim 1, wherein the alkyl alcohol is a primary, secondary or tertiary alkyl alcohol or an alcohol containing a cyclic aliphatic structure, with up to a maximum of 8 carbon atoms, for the final ring opening step. 12. A process as claimed in Claim 1, wherein the alkyl alcohol is methanol. 6 13.A process as claimed in Claim 1, wherein the non water miscible organic solvent is C 5-10 linear, branched or cyclic alkane or an ether for isolating the final product by extraction. 14.A process as claimed in Claim 13, wherein the non water miscible organic solvent is hexane. 7 There is disclosed a process for the preparation of alkyl ester of N-alkylanthranilic acid represented by Formula 1 wherein R1 and R2 contain from 1 to 8 carbon atoms, are alkyl, substituted alkyl, or alkyl containing a saturated ring, said process comprising the steps of: reacting 2H-3, l-benzoxazine-2. 4(lH)-dione (isatoic anhydride) in a polar aprotic organic solvent, such as herein described, as medium, with a solid metal hydroxide or basic metal oxide, such as herein described; adding an alkylating agent, such as herein described; reacting the intermediate with an alkyl alcohol, such as herein described; and isolating the product according to Formula 1 by adding water to the reaction mixture and extracting with a non water miscible organic solvent, such as herein described.

Full Text

Process for the preparation of alkyl N-alkylanthranilate
Technical field of the invention
The invention relates to a process for the preparation of alkyl N-alkylanthranilate of the Formula 1.
\ Wherein R1 and R2 contain from 1 to 8 carbon atoms, are alkyl, substituted alkyl, or alkyl containing
a saturated ring.
More particularly it is concerned with the preparation of
MethylN-methylanthranilate, Formula I, R1 = R2 = Me
Background of the invention
Methyl N-methylanthranilate (DMA) is a valuable compound used in the flavouring
and fragrance industry and is also reported to be a bird, repellent described in patent
US 2,967,128.
Several methods are known for the preparation of DMA.
A classical route is N-methyiation of methyl anthranilate with a methylating agent as
dimethyl sulfate or methyl iodide, cited in patent DE 3936229. To avoid
dimethylation, reductive methylation with formaldehyde and hydrogen has been
described in patent US 4633009. Reaction scheme I.

1

To prepare methyl anthranilate, 2H-3,l-benzoxazine-2,4 (lH)-dione (isatoic
anhydride) is reacted under alkaline conditions
with methano] as disclosed in patent IN 146359, Reaction scheme 2.

As disclosed by Staiger, J. Org. Chem. (1959), 24,1214-19 , N-methylisatoic anhydride reacts with methanol under alkaline conditions to produce Methyl N-raethylanthranilate.
Hardtmann, J. Heterocycl. Chem. (1975), 12 (3), 565-72 prepares N-substituted isatoic anhydride by reacting the N-sodium salt of isatoic anhydride, prepared from sodium hydride, with alkyi halides. The N-benzyl derivative of isatoic anhydride is prepared using potassium carbonate and benzyl chloride.
Disclosure of invention
It is an object of this invention to provide a fecile process for the preparation
of N-alkyl alkylanthranilates, specially N-methyl meihylaiithranilate, in commercial
quantities, good yield and high purity.
An obvious route would be a one pot synthesis starting with the ready available isatoic anhydride, N-alkylation and final reaction with an alcohol to furnish the title product. Accordingly, the present invention provides a process for the preparation of alkyi esters of N-alkylanthranilic acid represented by Formula 1

wherein R1 and R2 contain from 1 to 8 carbon atoms, are alkyl, substituted alkyl, or alkyl containing a saturated ring, said process comprising the steps of.
2

reacting 2H-3, l-benzoxazine-2,4 (lH)-dione (isatoic anhydride) in a polar aprotic organic solvent, such as herein described, as medium, with a solid metal hydroxide or basic metal oxide, such as herein described; adding an alkylating agent, such as herein described; reacting the intermediate with an alkyl alcohol, such as herein described; and
isolating the product according to Formula 1 by adding water to the reaction mixture and extracting with a non water miscible organic solvent, such as herein described.
Preferably, the polar aprotic solvent is selected from the group comprising of an aliphatic carboxamide, an aliphatic nitrile, an aliphatic ether, an aliphatic sulphoxide, or hexaalkyl phosphoric triamide. More preferably, the polar aprotic solvent is dimethyl formamide or 1 -methyl-2-pyrrolidinone.
Preferably, the solid metal hydroxide or basic metal oxide has the metal part selected from the group comprising of Li, Na, K, Ca and Ba. More preferably, the metal hydroxide is sodium hydr6xide or potassium hydroxide.
Preferably, the alkylating agent is an alkyl halide, wherein the alkyl group contains from 1 to 8 V carbon atoms, are alkyl substituted alkyl or alkyl containing a saturated ring and the halide is
represented by Cl, Br or I. More preferably, the alkylating agent is a dialkyl ester of sulfuric acid (dialkyl sulfate) wherein the alkyl group contains from 1 to 8 carbon atoms, are alkyl, substituted alkyl or alkyl containing a saturated ring.Most preferably the alkylating agent is dimethyl sulfate
Preferably, the alkyl alcohol is a primary, secondary or tertiary alkyl alcohol or an alcohol containing a cyclic aliphatic structure, with up to a maximum of 8 carbon atoms, for the final ring opening process. More preferably, the alkyl alcohol is methanol.
Preferably, the non water miscible organic solvent is a C 5-10 linear, branched, or cyclic alkane or an ether for isolating the final product by extraction. More preferably, the non water miscible organic solvent is hexane.
Surprisingly it turned out that a solid metal hydroxide or basic metal oxide, preferable sodium or pottasium hydroxide in a suitable polar solvent such as dimethylforamide or l-methyl-2-pyrrolidinone could form the N-metal salt with isatoic anhydride.

Depending on solvent, concentration or temperature the metal salt would separate
to form a dispersion.
One would anticipate that water formed during the salt formation immediately
would react with isatoic anhydride, forming anthranilic acid.
Surprisingly this was not the case.
Trials using metal alkoxides resulted in that the alkohols formed, reacted with
isatoic anhydride to form alkyl esters of anthranilic acid.
N-methylation could be achieved by adding an alkylation agent. Preferably
methyl iodide or dimethyl sulfate in a molar ratio, relative to isatoic anhydride,
from 1 to 5, preferably 1.5, at a temperature from 10 - 40 C. In the case of a
methylating agent, the intermediate N-methylisatoic anhydride could be isolated by
filtration as a colourless crystalline compound by adding 2 parts of water to the
reaction mixture. Identification was established by compare HPLC chromatograms
with authentic material (supplied by Aldrich).
After N-alkylation of isatoic anhydride has been performed 1 to 50 mole parts of an
alkyl allcohol, relative to isatoic anhydride, is added to the reaction mixture at a
temperature between 10 and 40°C. The temperature is elevated to distil excess of
alkyl alcohol off. Leaving 50% to 0% of the alcohol in the reaction mixture.
Preferably 10%.
By alcohol addition under alkaline conditions, N-alkylisatoic anhydride, is ring
opened, forming alkyl N-alkylanthranilate with subsequent elimination of
carbon dioxide.
Alkyl N-alkylanthranilate is isolated by adding 1 to 5 parts of water to the reaction
mixture, and extract the mixture with a non water miscible organic solvent.
The extraction solvent could be an alicyclic or cyclic hydrocarbon, halogenated
derivatives hereof, aliphatic ethers or esters. Preferably hexane.
The organic phase is washed with water, and evaporated in vacuo, leaving
alkyl N-allcylanthranilate as an oil with purity about 97% and yield
about 85%.
3

Examples
Products were analysed by gas chromatography. Using SRI Instruments model 310 equipped with column Restek, MXT-5, 15 m, 0.54 ID, FID detector and temperature gradient 90 - 200°C, 10° /min. Peaks were identified by running authentic samples.
Example 1
Methyl N-methvlantfrranilate
To dry Dimethylforamide (DMF), 300 mL, covered with nitrogene, solid pulverised
sodium hydroxide, 97% assay, 14.12 g, 0.3424 moles, is added.
Isatoic anhydride, 96% assay, 40.00 g, 0.2354 moles, is dissolved in dry DMF,
100 mL.
To the stirred suspension of sodium hydroxide covered with nitrogen, the solution of
isatoic anhydride is added at 30°C over 30 min. and the mixture is stirred for a
further 15 min.
Dimethyl sulfate, 32.88 g, 0.2588 moles is added drop wise with stirring over 20
min., allowing temperature to rise to max 45°C. The solution is stirred at ambient
temperature for a further 30 min.
Methanol, 50 mL, is added, the mixture is stirred for 15 min at 25°C.
Temperature is elevated to distil methanol off. When temperature reaches 100 C,
the mixture is cooled to 20°C and water, 800 mL is added. Ammonia solution,
2 mL, 25 w/w% is added to destroy excess dimethyl sulfate.
The cloudy mixture is extracted with hexane, 200 mL. The hexane phase is
separated, washed with water and distilled on a rotary evaporator at 15 mm Hg and
100°C leaving crude Methyl N-methylanthranilate, 33.80 g, with a composition, by
GC, of 2.1% Methyl anthranilate and 97.5% Methyl N-methylanthranilate,
corresponding to a yield of the theoretical of 85%.
Crude Methyl N-methylanthranilate, 33,80 g, is distilled through a 30 cm Vigreux
column at 130 - 131°C at 15 mm Hg, giving 28.10 g Methyl N-methylanthranilate
with a composition, by GC, of 1.5% Methyl anthranilate and
98.5% Methyl N-methylanthranilate.
4

Example 2
To dry Dimethylforamide (DMF), 75 mL, covered with nitrogene, solid pulverised potassium hydroxyde, 85% assay with 15% water, 5.80 g, 0.0879 moles, is added. Isatoic anhydride, 96% purity, 10.00 g, 0.0588 moles, is dissolved in dry DMF, 35 mL.
To the stirred suspension of potassium hydroxide covered with nitrogen, the solution of isatoic anhydride is added at 30°C over 30 min. and the mixture is stirred for a further 15 min.
Methyl iodide, 12.50 g, 0.0883 moles is added drop wise with stirring over 20 min., allowing temperature to rise to max 40°C. The solution is stirred at ambient temperature for a further 30 min.
Methanol, 50 mL, is added, the mixture is stirred for 15 min at 25°C. Temperature is risen so methanol is distilled off. When temperature reaches 100 C, the mixture is cooled to 20°C and water, 200 mL is added, and the mixture is extracted with 2 times hexane. The combined hexane phases are washed with water and distilled on a rotary evaporator at 15 mm Hg and 100°C leaving crude Methyl N-methylanthranilate, 8.10 g, with a composition, by GC, of 4.4% Methyl anthranilate and 95.3% Methyl N-methylanthranilate, corresponding to a yield of the theoretical of 80%.

1: Aprocess for the preparation of alkyl esters of N-alkylanthranilic acid represented by Formula 1

wherein R1 and R2 contain from I to 8 carbon atoms, are alkyl, substituted alkyl, or alkyl containing
a saturaieanng, said'process comprising the steps of:
reacting 2H-3, l-benzoxazine-2,4 (lH)-dione (isatoic anhydride) in a polar aprotic organic solvent,
such as herein described, as medium, with a solid metal hydroxide or basic metal oxide, such as
herein described; adding an alkylating agent, such as herein described; reacting the intermediate
with an alkyl alcohol, such as herein described; and
isolating the product according to Formula 1 by adding water to the reaction mixture and extracting
with a non water miscible organic solvent, such as herein described.
2.A process as claimed in Claim 1 wherein R1and R2 are both methyl.
3 .A process as claimed in Claim 1, wherein the polar, aprotic solvent is selected from the group comprising of an aliphatic carboxamide, an aliphatic nitrile, an aliphatic ether, an aliphatic sulphoxide or hexaalkylphosphoric triamide.
4. A process as claimed in Claim 1, wherein the polar, aprotic solvent is dimethylformamide or 1 -methyl-2-pyrrolidinone.

5.A process as claimed in Claiml, wherein the solid base is a metal hydroxide and the metal part is selected from the group comprising of Li, Na, K, Ca and Ba.
6.A process as claimed in Claiml, wherein the metal hydroxide is sodium hydroxide or potassium hydroxide.
7. A process as claimed in Claiml, wherein the solid base is a metal oxide and the metal part is selected from the group comprising of Li, Na, K, Ca and Ba.
8.A process as claimed in Claim 1, wherein the, alkylating agent is an alkyl halide and the alkyl group contains from 1 to 8 carbon atoms, are alkyl, substituted alkyl, or alkyl containing a saturated ring, and the"halide"part is selected from the group comprising of Cl, Br and I.
9.A process as claimed in Claim 1, wherein the alkylating agent is a dialkyl ester of sulfuric acid (dialkyl sulfate), and the alkyl group contains from 1 to 8 carbon atoms, are alkyl, substituted alkyl or alkyl containing a saturated ring,
10.A process as claimed in Claim 1, wherein the alkylating agent is dimethyl sulfate.
11.A process as claimed in Claim 1, wherein the alkyl alcohol is a primary, secondary or tertiary alkyl alcohol or an alcohol containing a cyclic aliphatic structure, with up to a maximum of 8 carbon atoms, for the final ring opening step.
12. A process as claimed in Claim 1, wherein the alkyl alcohol is methanol.
6

13.A process as claimed in Claim 1, wherein the non water miscible organic solvent is C 5-10 linear, branched or cyclic alkane or an ether for isolating the final product by extraction.
14.A process as claimed in Claim 13, wherein the non water miscible organic solvent is hexane.
7
There is disclosed a process for the preparation of alkyl ester of N-alkylanthranilic acid represented by Formula 1
wherein R1 and R2 contain from 1 to 8 carbon atoms, are alkyl, substituted alkyl, or alkyl containing a saturated ring, said process comprising the steps of:
reacting 2H-3, l-benzoxazine-2. 4(lH)-dione (isatoic anhydride) in a polar aprotic organic solvent, such as herein described, as medium, with a solid metal hydroxide or basic metal oxide, such as herein described; adding an alkylating agent, such as herein described; reacting the intermediate with an alkyl alcohol, such as herein described; and isolating the product according to Formula 1 by adding water to the reaction mixture and extracting with a non water miscible organic solvent, such as herein described.

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Patent Number

206732

Indian Patent Application Number

00287/KOLNP/2003

PG Journal Number

19/2007

Publication Date

11-May-2007

Grant Date

10-May-2007

Date of Filing

07-Mar-2003

Name of Patentee

PROM LIMITED

Applicant Address

PROM HOUSE,89 HIGH STREET,CATERHAM CR3 5UH,

Inventors:

#	Inventor's Name	Inventor's Address
1	BERG CASTEN	AALEBAEK STRANDVEJ 28,DK-4791 BORRE DENMARK

PCT International Classification Number

C07C-227/17,229/56

PCT International Application Number

PCT/GB00/03808

PCT International Filing date

2000-10-04

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA