<i>N</i>‐ethoxycarbonylamidines as starting materials and intermediates in the synthesis of heterocyclic compounds

Abstract

Abstract Treatment of N ‐ethoxycarbonylthioamides ( 1 ) with primary aromatic amines yields N ‐aryl‐ N ′‐ethoxy‐carbonylamidines ( 2 ), which thermally cyclize to 2‐aryl‐4(3 H )‐quinazolinones ( 6 ). Analogous reactions of 1 with ethyl 3‐aminocrotonate and with 2‐amino‐2‐thiazoline lead respectively to ethyl 2‐aryl‐3,4‐dihydro‐6‐methyl‐4‐oxo‐5‐pyrimidinecarboxylates ( 10 ) and to 2‐aryl‐6,7‐dihydro‐4 H ‐thiazolo[3,2‐ a ]‐1,3,5‐triazin‐4‐ones ( 14 ), presumably through the corresponding N ‐ethoxycarbonylamidines.