Process for the preparation of 2,3-quinolinedicarboxylic acids

Claim 1

A method for the preparation of a quinoline-2,3-dicarboxylic acid having the structure: ##STR17## wherein L and Q are each hydrogen and M and R 7 , are each H, CF 3 , NO 2 or difluoromethoxy; with the proviso that only one of M and R 7 , may represent a substituent other than hydrogen; comprising, admixing a compound having the structure: ##STR18## wherein R" is hydrogen or C 1 -C 4 alkyl and L, M, Q and R 7 , are as described above, or the compounds 3-methyl-2-quinolinecarboxylic acid or ethyl 3-methyl-2-quinolinecarboxylate with a sufficient quantity of water to give a 0.02 to 1.0M solution of said compound and adding thereto about 5-15% by weight of an aqueous alkali metal hydroxide; agitating the thus-formed mixture and admixing therewith from about 3.0 to 4.0 molar equivalents of nickel peroxide while maintaining the temperature of the reaction mixture at from 0° to 30° C. until oxidation of the methyl function, if R" is hydrogen, or oxidation of the methyl function and simultaneous hydrolysis of the ester function, if R" is C 1 -C 4 alkyl, of the 2-methyl-3-quinolinecarboxylic acid; 3-methyl-2-quinolinecarboxylic acid, or the alkyl esters thereof, is essentially complete and, thereafter adjusting the pH of the reaction mixture to about pH 2, to obtain the quinoline-2,3-dicarboxylic acid.

Claim 2

A method for the preparation of a quinoline-2,3-dicarboxylic acid having the structure: ##STR17## wherein L and Q are each hydrogen and M and R 7 , are each H, CF 3 , NO 2 or difluoromethoxy; with the proviso that only one of M and R 7 , may represent a substituent other than hydrogen; comprising, admixing a compound having the structure: ##STR18## wherein R" is hydrogen or C 1 -C 4 alkyl and L, M, Q and R 7 , are as described above, or the compounds 3-methyl-2-quinolinecarboxylic acid or ethyl 3-methyl-2-quinolinecarboxylate with a sufficient quantity of water to give a 0.02 to 1.0M solution of said compound and adding thereto about 5-15% by weight of an aqueous alkali metal hydroxide; agitating the thus-formed mixture and admixing therewith from about 3.0 to 4.0 molar equivalents of nickel peroxide while maintaining the temperature of the reaction mixture at from 0° to 30° C. until oxidation of the methyl function, if R" is hydrogen, or oxidation of the methyl function and simultaneous hydrolysis of the ester function, if R" is C 1 -C 4 alkyl, of the 2-methyl-3-quinolinecarboxylic acid; 3-methyl-2-quinolinecarboxylic acid, or the alkyl esters thereof, is essentially complete and, thereafter adjusting the pH of the reaction mixture to about pH 2, to obtain the quinoline-2,3-dicarboxylic acid.