A Convenient and Facile Hantzsch Synthesis of Aryl Imidazo[1,2‐b]Isoxazolyl‐N‐aryl Thiazol Amines

Abstract

The Hantzsch synthesis of novel aryl imidazo[1,2‐b]isoxazolyl‐N‐aryl thiazol amines 5 analogues were described. Reaction of 3‐aminoisoxazole 1 with substituted phenacyl bromides 2 in dry ethanol afforded the corresponding 6‐methyl‐3‐arylimidazo[1,2‐b]isoxazoles 3 in good yields. Compounds 3 on reaction with chloroacetyl chloride in 1,4‐dioxane furnished the corresponding 2‐chloro‐1‐(6‐methyl‐3‐arylimidazo[1,2‐b]isoxazol‐2‐yl)ethanones 4. Compounds 4 on heating with N‐aryl thioureas in an oil bath underwent cyclization to afford the title compounds viz., imidazo[1,2‐b]isoxazolyl‐N‐aryl thiazol amines 5 in moderate to good yields by Hantzsch synthesis.

Aminoazole-Based Diversity-Oriented Synthesis of Heterocycles

“…3-Amino-5-methylisoxazole was sometimes considered as a 1,3-binucleophile reacting with the preservation of the isoxazole moiety. However, in some cases establishing structures of the compounds synthesized without X-Ray data was not sufficient (Rajanarendar et al, 2016 ; Diyanatizadeh and Yavari, 2017 ). Sometimes the structures of final compounds were assigned similarly with the pyrazole-containing compounds, which in our opinion may be incorrect due to the possibility of isoxazole ring opening.…”