Straightforward microwave-assisted synthesis of 1-carboxymethyl-5-trifluoromethyl-5-hydroxy-4,5-dihydro-1H-pyrazoles under solvent-free conditions

✍ Scribed by Marcos A. P. Martins; Paulo H. Beck; Dayse N. Moreira; Lilian Buriol; Clarissa P. Frizzo; Nilo Zanatta; Helio G. Bonacorso

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2010
• Tongue: English
• Weight: 929 KB
• Volume: 47
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.309

✦ Synopsis

Abstract

magnified image
An efficient microwave‐assisted synthesis of 1‐carboxymethyl‐5‐trifluoromethyl‐5‐hydroxy‐4,5‐dihydro‐1__H__‐pyrazoles from the cyclocondensation reaction between enones [CF~3~C(O)C(R^2^) = C(R^1^)(OR), where R^2^ = H, Me; R^1^ = H, Me, Et, Pr, i‐Pr, t‐Bu, i‐Bu, Ph, 4‐NO~2~‐Ph, 4‐Cl‐Ph, 4‐Br‐Ph, 4‐F‐Ph and R = Me, Et] and methyl hydrazinocarboxylate under solvent‐free conditions is reported. This process is an efficient alternative to the traditional thermal heating and furnishes the heterocyclic compounds in good to excellent yields in a short reaction time. To show the versatility of 1‐carboxymethyl‐5‐trifluoromethyl‐5‐hydroxy‐4,5‐dihydro‐1__H__‐pyrazoles, dehydration reactions of these compounds are also demonstrated. J. Heterocyclic Chem., (2010).