The occurrence of a diphenyl isatin in california prunes

Abstract

A commercial water concentrate of California prunes was extracted with chloroform-ethanol solutions which were washed with water to remove dispersed impurities. Evaporation of chloroform revealed a mixture of amorphous and crystalline materials that yielded negative tests for hydroxyanthraquinones and their derivatives, but positive reactions for a diphenyl isatin. A quantitative estimation for dihenyl isa-tins was devised using di(acetylhydroxyphenyl)isatin as a reference stansard based on photometric determinations of color development when diphenyl isatins are treated with sodium hydroxide and potassium ferricyanide solutions.