Synthesis and Comparative Cytostatic Activity of the New N-7 Acyclic Purine Nucleoside Analogues with Natural N-9 Regioisomers

The synthesis of the purine derivatives alkylated at N-7 (2a) and N-9 (2b) with 2-acetoxyethoxymethyl side chain, and chemical transformations of keto to chloro (5a), chloro to thio (6a) at C-6, and amino to fluoro (7a) at C-2 position of the purine ring were described.Structures of compounds were elucidated by analysis of their 1 H and 13 C NMR spectra, MS spectra and elemental analyses.N-7 Regioisomers (2a-7a) were evaluated for their cytostatic activities and their inhibitory effects were compared with those of the corresponding N-9 isomers.The 2-aminopurin-6-thione derivative (6a) showed the highest cytostatic activity, particularly against murine leukemia (L1210).