Facile microwave-assisted synthesis of 2-aryloxazolo[4,5-b]pyridines using SBA-Pr-NH2

Abstract

In this work, amino-functionalized SBA-15 (SBA-Pr-NH 2 ) has been used as a basic nano-catalyst in the one-pot synthesis of 2-aryloxazolo [4,5-b]pyridines by the condensation reaction of 2-amino-3-hydroxypyridine and benzoyl chlorides under microwave irradiation in solvent free conditions. Among the advantages of this work are short reaction times, high yields and simple work-up. SBAPr-NH 2 as an efficient heterogeneous nanoporous solid basic catalyst which was prepared by silica functionalization with 3-aminopropyltriethoxysilane, can be easily removed from the reaction mixture by simple filtration, and also recovered and reused without noticeable loss of reactivity. 2-Aryloxazolo[4,5-b]pyridines have different pharmacological activities (anti-inflammatory, anti-pyretic, analgesic, antifungal). In the current method for the synthesis of 2-aryloxazolo [4,5-b]pyridines, no hazardous organic solvent was used and simplicity of the procedure provides significant improvements over many of other existing methods. Furthermore, the SBA-15-Pr-NH 2 with pore size of 6 nm can act as nano-reactor.

Recent Development and Green Approaches for Synthesis of Oxazole Derivatives: A Review

“…Ziarani et al [51] investigate the synthesis of novel benzoxazole derivatives by performing a condensation reaction between 2-amino-3hydroxypyridine and benzoyl chloride using Santa Barbara Amorphous-15 (SBA-15) as a basic nanocatalyst in microwave irradiation and solvent free conditions. This reaction proceeds in two ways by using DMF as solvent at optimum temperature in the presence of SBA-15, resulting in the formation of N-(3-hydroxy-2-pyridyl) Benzamide and substituted benzoic acid as an intermediate.…”