Hydrochloric Acid → Methyl 2-hydroxy-1-methoxy-5-methyl-4-oxocyclohex-2-enecarboxylate

Participants

Reaction Conditions

Reaction Steps

A 30% solution of 35.8 g of sodium methanolate is made up in 65 ml of dimethyl sulfoxide and, over a period of 20 minutes, is treated at a temperature of from 30 to 35° C. with a mixture of 16.7 g of 3-methyl-3-buten-2-one and 32.4 g of methoxymalonic acid dimethyl ester. The mixture is stirred for 1 hour at a temperature of 35° C., acidified with hydrochloric acid and then extracted several times with dichloromethane. The organic phases are washed with water, dried and concentrated. By crystallising from hot ethyl acetate and hexane, pure 2-hydroxy-1-methoxy-5-methyl-4-oxo-cyclohex-2-enecarboxylic acid methyl ester having a melting point of 117-117.5° C. is obtained.

Provenance & Evidence