Microwave-Assisted Synthesis of s-Triazino[2,1-b][1,3]benzoxazoles, s-Triazino[2,1-b][1,3]benzothiazoles, and s-Triazino[1,2-a]benzimidazoles [1]

Abstract

2-Amino-4-oxo-derivatives of s-triazino[2,1-b][1,3]benz­oxazoles, s-triazino[2,1-b][1,3]benzothiazoles, and s-triazino[1,2-a]benzimidazoles were synthesized by carbonylation of 2-benz­oxazolylguanidines, 2-benzothiazolylguanidines, and 2-benzimidazolylguanidines with phenyl isocyanate under microwave irradiation (180 °C, 15 minutes). Using phenyl isothiocyanate instead of phenyl isocyanate under the same conditions led to the successful­ ring closure via thiocarbonylation of 2-benz­oxazolylguanidines. However, the formation of 2-imino-4-phenylimino­-s-triazino[2,1-b][1,3]benzothiazoles from 2-benzo­thiazolylguanidines was observed instead under microwave irradi­ation conditions.

Key words

carbonylation - microwave irradiation - triazinobenzoxazoles - triazinobenzothiazoles - triazinobenzimidazoles

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