NOVEL BETULINIC ACID DERIVATIVES

摘要

The invention relates to novel betulinic acid derivatives of formula (I), wherein R is C (=CH₂) CH₃ or CH(CH₃) ₂; R₂ together with the adjacent carbonyl group forms a carboxylic acid, carboxylic acid ester or amide or substituted amide; R₃ or R₄ are hydrogen or aryl with the proviso that both are not independently hydrogen or alkyl or R₃ and R₄ are combined together to form an aryl ring optionally substituted with a group X, wherein X is selected from halogen, alkyl, cyano, nitro, alkoxy, amino or substituted amine; Y is N or O; and R₁ is zero when Y is O, and R₁ is hydrogen, alkyl or aryl alkyl when Y is N, useful for inhibition of tumor cancer cells. Formula (I)