Acid-Catalyzed, Silica-Supported, One-Pot Benzoylation Route to Synthesize 2-(Substituted Phenyl)oxazolo[4,5-b]pyridines Under Ambient Conditions

Abstract

Present paper elicits the silica supported perchloric acid catalyzed efficient protocol for the synthesis of 2-(phenyl)oxazolo[4,5-b]pyridine derivatives. The remarkable feature of this strategy embraces the high conversion, simple work-up procedures, ambient conditions, short reaction time and reusability of the catalyst. Structures of the synthesized compounds have been established on the basis of elemental analysis and spectral data (IR, 1 H NMR, 13 C NMR, and mass spectrometry). Moreover, in order to investigate the mechanistic details of the reaction and to ascertain the regioselective outcome of the product, local nucleophilicity descriptors N k at B3LYP/6-311G++(d, p) level were determined and analyzed. KEYWORDS: Silica supported perchloric acid (HClO 4 ·SiO 2 ), benzoylation, oxazolo[4,5-b]pyridine, local nucleophilicity index.

Multiwalled carbon nanotubes crowned with nickel‐ferrite magnetic nanoparticles assisted heterogeneous catalytic strategy for the synthesis of benzo[d]imidazo[2,1‐b]thiazole scaffolds

“…[24] Also, despite the diversified advantages associated with carbon nanotubes, its use as a catalyst is hitherto unrivaled, although this can leads to the expedient synthesis of imidazo fused benzothiazole scaffolds. On keeping these observations in mind and continuation of our interest toward nanocatalysis, [25][26][27][28][29] we propose an alternative eco-friendly synthetic methodology for the synthesis of highly functionalized benzo[d]imidazo [1,2-b]thiazoles using multiwall carbon nanotubes mediated with nickelferrite magnetic nanoparticles (NiFe 2 O 4 -CNTs), as an efficacious, economical and noncorrosive heterogeneous catalyst, under aerobic conditions via. A 3 coupling followed by 5-exo-dig cyclization.…”