Preparation of pure gossypol from dianilinogossypol

Summary A simple method has been developed for the acid hydrolysis of dianilinogossypol, resulting in gossypol yields of about 86%. The gossypol may be readily purified by recrystallization as gossypol‐acetic acid from a mixture of ethyl ether and acetic acid. After removal of the acetic acid the gossypol may be crystallized either from a mixture of ether and light petroleum ether or from a mixture of ether, ethanol, and water. Crystallization from the latter mixture results in a yield of about 75% of gossypol, based on the amount of dianilinogossypol hydrolyzed, with a high degree of purity as is indicated by spectrophotometric and titrimetric methods.