4- Oxocyclohexane-carboxylic acid

After 24 hr, the reaction mixture is diluted with chloroform (80 mL), and washed with water (150 mL) and 3 M sulfuric acid (2 x 150 mL). The water and sulfuric acid washings are each washed (Note 12) with 100 mL of chloroform. The combined chloroform extracts are washed with water (2 x 250 mL), dried with magnesium sulfate, and the solvent removed to give an orange-colored oil (10.3 g) which slowly crystallizes on standing. Crystallization from hexane (Note 5) gives 9.4 g (82%) of ethyl l-(p-methoxyphenyl)-2-oxocyclohexane-carboxylate, mp 49-50°C. 

A = l-hydroxy-6-oxocyclohex-2-en-l-carboxylic acid B = l,2,3-trihydroxy-6-oxocyclohexan-l-carboxylic acid C = l,2,6-trihydroxy-5-oxocyclohex-3-en-l-carboxylic acid D = 2-(2-oxo-2-phenyl)ethylbenzoic acid... 

Reactions of 2-aminopyridines and diethyl 2-aryl-4-hydroxy-4-methyl-6-oxocyclohexane-l,3-dicarboxylate (309) in acetic acid for 4 h gave either ethyl 1,2-dihydro-l 1-oxo-l l//-pyrido[2,l -6]quinazoIine-2-carboxylates (310) or their isomeric ethyl 7,8-dihydro-6-oxo-6//-pyrido[l,2-a]quinazoline-8-carboxylates (311) (92PHA336). 

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