Some short-chain N6-substituted adenosine analogues with antitumor properties

The compounds N6-allyl-, N6-isopropyl-, N6-propargyl-, and N6-(2-methylallyl)adenosine were prepared by reacting 6-chloropurine riboside with an excess of the corresponding amines in ethanol, in the presence of two acid acceptors resulting in virtually quantitative yields. The compounds showed biological activity in a number of in vitro and in vivo tumor cell systems. Very good increases in life spans of mice bearing mammary carcinoma were obtained by treatment with the N6-allyl, N6-isopropyl, and N6-propargyl analogues, respectively. In rats, the N6-allyl analogue slowed the rate of transplantable mammary tumor growth by one-fourth. The short-chain adenosine analogues are more active in the treatment of animal carcinomas than in the leukemia or sarcoma tumor cell systems.