Methanol → HCID 12719792, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of 31.0 kg 1-(3,4-dichlorophenyl)-1,2-cyclopropane-dicarboxylic acid dimethyl ester (from Step 2), 40 L water, 35 kg methanol and 18.0 kg 50% caustic soda was warmed to 70-75° C. (under reflux) and maintained at 70-75° C. for 1.5 hours. 10 L water was then added, and the mixture was kept at 75-77° C. for an additional 2 hours. Methanol was slowly distilled off in vacuo to 70° C. to give a heavy suspension, which was then mixed with 80 L water to effect solution. The free dicarboxylic acid was precipitated with 31 kg of 32% hydrochloric acid and extracted with 100 kg ethyl acetate. The lower aqueous phase was separated and washed with 20 kg ethyl acetate. The combined organic phases were washed with 50 L water, and then saturated aqueous sodium chloride. Distillation in vacuo to 80° C. with full vacuum yielded a concentrate of 1-(3,4-dichlorophenyl)-1,2-cyclopropane-dicarboxylic acid, which was used “as is” for the next step, cyclization to the imide. A quantitative yield from the diester was assumed for calculation purposes.

Provenance & Evidence