Studies on Quinones. V. : On the Reaction of Naphthoquinone Derivatives with Active Methylene Compounds, the Craven Reaction

Abstract

The coloration reaction, the so-called Craven reaction, of 1, 2-and 1, 4-naphthoquinones, and their derivatives with active methylene compounds, such as cyanoacetic acid esters and malonic acid diesters, in ammoniac alkalinity, was examined. 2-Methyl-, 3-methoxy-2-methyl-, and 3-chloro-2-methyl-1, 4-naphthoquinones react with cyanoacetate under dehydrogenation, demethoxylation, and dechlorination, respectively, to give the same product, while 2-methyl-1, 4-naphthoquinone alone reacts with malonic acid diester. Hydrolysis of these condensates in alcohol was found to produce 2-methyl-1, 4-naphtho-quinone-3-acetic acid and its ester. Reduction of these condensates with zinc in acetic anhydride and hydrolysis of its product were carried out and structure of the end product was elucidated. The same condensation products were obtained from 2, 3 -dichloro-, 2-chloro-3-methoxy-, 3-acetoxy-2-chloro-, and 2-chloro-1, 4-naphthoquinones. Condensation of 1, 4-naphthoquinone under dehydrogenataion was presumed from mutual reaction of 1, 4-naphthoquinone derivatives. Since a 4-substituted condensation product is obtained from 1, 2-naphthoquinone, this reaction was found to progress under dehydrogenation, as in the case of the above 1, 4-naphthoquinone derivatives.