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Microwave-Assisted Synthesis of New N1,N4-Substituted Thiosemicarbazones
Departamento de Química, Instituto de Ciências Exatas, Universidade Federal Rural do Rio de Janeiro, 23890-000, Seropédica, Rio de Janeiro, Brazil
Departamento de Micologia, Instituto Oswaldo Cruz – FIOCRUZ, 21045-900, Rio de Janeiro, Rio de Janeiro, Brazil
* Author to whom correspondence should be addressed.
Received: 5 October 2011; in revised form: 6 December 2011 / Accepted: 16 December 2011 / Published: 20 December 2011
Abstract: We present an efficient procedure for the synthesis of thirty-six N1,N4-substituted thiosemicarbazones, including twenty-five ones that are reported for the first time, using a microwave-assisted methodology for the reaction of thiosemicarbazide intermediates with aldehydes in the presence of glacial acetic acid in ethanol and under solvent free conditions. Overall reaction times (20–40 min when ethanol as solvent, and 3 min under solvent free conditions) were much shorter than with the traditional procedure (480 min); satisfactory yields and high-purity compounds were obtained. The thiosemicarbazide intermediates were obtained from alkyl or aryl isothiocyanates and hydrazine hydrate or phenyl hydrazine by stirring at room temperature for 60 min or by microwave irradiation for 30 min, with lower yields for the latter. The preliminary in vitro antifungal activity of thiosemicarbazones was evaluated against Aspergillus parasiticus and Candida albicans.
Keywords: thiosemicarbazone; thiosemicarbazide; microwave irradiation; antifungal activity
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Reis, C.M.; Pereira, D.S.; Paiva, R.O.; Kneipp, L.F.; Echevarria, A. Microwave-Assisted Synthesis of New N1,N4-Substituted Thiosemicarbazones. Molecules 2011, 16, 10668-10684.
Reis CM, Pereira DS, Paiva RO, Kneipp LF, Echevarria A. Microwave-Assisted Synthesis of New N1,N4-Substituted Thiosemicarbazones. Molecules. 2011; 16(12):10668-10684.
Reis, Camilla Moretto dos; Pereira, Danilo Sousa; Paiva, Rojane de Oliveira; Kneipp, Lucimar Ferreira; Echevarria, Aurea. 2011. "Microwave-Assisted Synthesis of New N1,N4-Substituted Thiosemicarbazones." Molecules 16, no. 12: 10668-10684.