Synthesis and in vitro evaluation of some new pyrimidines and related condensed ring systems as potential anticancer agents

Several new pyrimidines 6–11, 18–20, furo‐, thieno‐, and pyrrolo[2,3‐d]pyrimidines 3, 8, 12, triazolo‐[4,3‐a]pyrimidines 14, 15, 16 and tetrazolo[1,5‐a]pyrimidine 17 were prepared from the known intermediate 5‐(2‐hydroxyethyl)‐6‐methyl‐2‐thiouracil (2). Compound 7 (4‐chloro‐5‐(2‐chloroethyl)‐2‐methylthio‐6‐methyl‐pyrimidine) exhibited weak antitumor activity in vitro.