Green Synthesis of Pyrazole and Oxazole Derivatives

Abstract

New intermediate 3‐methyl‐5‐oxopyrazol propanenitrile was synthesized by one pot three component reactions using ethyl cyanoacetate, hydrazine hydrate, and ethyl acetoacetate and was used for the synthesis of new oxazole and pyrazole derivatives. All reactions were carried out using eco‐friendly solvents and without catalyst.

3-(Bromoacetyl)coumarins: unraveling their synthesis, chemistry, and applications

“…Eco-friendly approach to accesses 3-methyl-1-(2-(4-(2-oxo-2 H -chromen-3-yl)oxazol-2-yl)acetyl)-1 H -pyrazol-5(4 H )-one 57 was carried out without using any catalyst through the reaction of 3-(bromoacetyl)coumarin 1 with 3-oxopropanamide 56 in ethanol under heating ( Scheme 27 ). 83 …”

Silica sulfuric acid mediated synthesis of naphtho[2,1‐b]furan derivatives and development of one‐pot multicomponent synthesis of substituted pyrazole derivatives

“…In general, the synthesis of pyrazoles can be achieved by reacting (substituted) hydrazines with β‐functional (either 1,3‐dicarbonyl compounds or α,β‐unsaturated compounds) compounds, 1,3‐dipolar cycloaddition with diazo compounds, degradation of fused pyrazole, and rearrangement of other monocyclic heterocycles under chemical, thermal, and photochemical conditions [29]. Due to the broad spectrum of applications of pyrazole moiety the synthesis of diversified pyrazole derivatives has been a continuously challenging task to synthetic organic chemist [30–33]. Shang and co‐workers employed SSA as a heterogeneous catalyst for the synthesis of series of substituted pyrazole derivatives from the reaction of hydrazines with 1,3‐dicarbonyl compounds [34].…”