Quinazolines. VII. Synthesis of 1,3‐Diamino‐5,6‐dihydrobenzo[f]quinazolines

Abstract
Eighteen new 1,3‐diamino‐5,6‐dihydrobenzo[f] quinazolines (6, R. = alkyl, Cl, MeO) were synthesized via the condensation of appropriate 2‐tetralones with cyanoguanidine under fusion conditions. Methods were developed for the preparation of a number of heretofore undescribed 2‐tetralones as precursors. The final products can be viewed as conformationally rigid analogs of pyrimethamine (2), and are of interest as inhibitors of dihydrofolate reductase and as potential antimalarial and antitumor agents.