ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

2-(3-acylthioureido)benzonitriles. 2. Synthesis of N-substituted 2,4-diaminoquinazolines

P. Pazdera and V. Potůček

Department of Organic Chemistry, Faculty of Natural Sciences, Masaryk University, CS-611 37 Brno

Abstract: Desulfanation reaction of 2-(3-acylthioureido)benzonitriles (I) with mercuric oxide in the presence of aniline, ethyl- and diethylamine in acetonic solution at room temperature led in dependence on the type of starting acyl thioureido derivative and amine to either N-phenyl-N'-acetyl-N"-(2-cyanophenyl)guanidine (II) and N,N-diethyl-N'-acyl-N"-(2-cyanophenyl)guanidine (V), respectively or the products of their cyclization, i.e. 3-substituted 2-acylamino-4-imino-3,4-dihydroquinazoline (III) or 3-acyl-2-diethylamino-4-imino-3,4-dihydroquinazoline (VI) and the products of their rearrangement, i.e. 4-acylamino-2-(diethylamino)quinazolines (VII). Compounds II and III underwent a base-catalyzed rearrangement with simultaneous hydrolysis of the acyl group to 2-amino-4-(R'-amino)quinazolines (IV) and compounds V, VI, and VII to 4-amino-2-diethylaminoquinazoline (VIII). This gave by acylation with acyl chloride in benzene in the presence of triethylamine compound VII only, although its acetylation with acetic anhydride in pyridine gave a mixture of VI and VII.

Full paper in Portable Document Format: 455a677.pdf

Chemical Papers 45 (5) 677–686 (1991)