Benzene → 3-Hydroxy-5-keto-4-phenylazo-3-cyclohexenecarboxylic acid methyl ester

Participants

Reaction Steps

60 G. of 3-hydroxy-5-keto-4-phenylazo-3-cyclohexene-carboxylic acid, 200 ml. of methanol, 1200 ml. of benzene and 5 g. of p-toluenesulfonic acid were boiled together under reflux on a water separator for 18 hours. After cooling, the solution was washed with 500 ml. of a 5% sodium bicarbonate solution, then washed with water, dried and evaporated. The residue was dissolved in ethyl acetate and purified on an aluminum oxide column (500 g.; activity stage I). After evaporation of the ethylacetate, there was obtained 3-hydroxy-5-keto-4-phenylazo-3-cyclohexene-carboxylic acid methyl ester as a solid having a melting point of 144° C.

Provenance & Evidence