Nucleosteroids: carbocyclic nucleoside analogs of androst-4-en-17 beta-ol

Steroidal nucleoside analogs were synthesized starting from testosterone. By reduction of the oxime of 17 beta-hydroxy-androst-4-en-3-one (testosterone), a mixture of the two amino epimers of C-3 were obtained. The 3 alpha-amino-androst-4-en-17 beta-ol was crystallized in 73% yield and coupled with 5-amino-4,6-dichloropyrimidine to give 3 alpha-(5'-amino-4'-chloro-pyrimidin-6'-yl)amino-androst-4-en-17 beta-ol. This compound was treated with triethyl orthoformate in acid media to give the corresponding purinyl steroid adduct 3 alpha-(6'-chloro-purin-9'-yl)-androst-4-en-17 beta-ol in 98% yield. This substance, in turn, was converted with good yield into the 6'-thio, 6'-methylamino, and 6'-diethyl aminopurinyl derivatives through nucleophilic reactions at C-6 of the purine nucleus.