Heterocyclic compounds. VI. Synthesis of poly nuclear thienopyrimidine derivatives

Quinazoline derivatives have received great interest because of their potential biological activity. This communication describes a facile method for the synthesis of substituted thiophenopyrimidones. 2‐Amino‐3‐earbethoxy‐4,5‐tetramethylenethiophene on heating with substituted imidoyl‐chlorides, iminoethers, iminothioethers or thioamides affords thiophenopyrimidones. By using this method a number of such compounds of varying complexity were synthesized which are otherwise not so easily accessible.