Synthesis and Biological Activities of Some Condensed Oxazine and Pyrimidine Derivatives: Cyclization, Ring Transformation and Functionalization of Oxazine

Abstract

2-Amino benzoic acid was acylated using chloroacetyl chloride followed by cycloaddition with benzylidene derivative to yield pyrimidine 3. Benzoxazone 4 reacted with nucleophilic carbon of phenols 5 and 6, active methylene compounds 11 and 12, and enaminic carbons of 16 and 17 to yield compounds 7, 10, 13, 14, 18 and 19 respectively. Also, benzoxazone 6 reacted with hydrazine to yield compounds 5 and 33. Aminoquinazoline 5 underwent a series of reactions using benzaldhyde, NH 4 SCN in base/acid medium, chloroacetyl chloride and CS 2 followed by cyclization using ethyl chloroacetate to yield compounds 22, 26, 29, 32, 30 and 31 respectively. Hydrazide 33 underwent a series of cycloaddition and cyclocondensation reactions using compounds like ethyl chloroacetate and/or acetyl acetone, maleic anhydride and p-chlorocinnamoyl isothiocyanate to yield compounds 34, 36, 37 and 40 respectively. Finally, compound 6 was reacted with ethyl cyanoacetate and/or acetyl acetone to form compounds 43 and 44 respectively.