Microwave-Assisted Synthesis of New N1,N4-Substituted Thiosemicarbazones

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.

New Platinum(II) Triazole Thiosemicarbazone Complexes: Analysis of Their Reactivity and Potential Antitumoral Action

“…Synthesis of H 3 L:3 ,5-Diacetyl-1,2,4-triazole and 4-N-isopropylthiosemicarbazide were used as starting materials and synthesized by following general procedures described in the literature. [26,27] Analytical and spectroscopic properties were consistent with those [25] [a] n.r. : no response (IC 50 > 100 mm).…”

Synthesis and Bioactivity of Thiosemicarbazones Containing Adamantane Skeletons

“…In this study, 4-(1-adamantyl)-3-thiosemicarbazide (1) was synthesized by the reaction of adamantan-1-yl isothiocyanate (Sigma Aldrich, MO, USA) with 80% hydrazine hydrate solution (Sigma Aldrich, St. Louis, MO, USA) in toluene under microwave irradiated conditions for 30 min at 100 W following the same method as a previous publication [47]. Common chemicals such as methanol (MeOH), acetic acid (AcOH), substituted benzaldehydes and acetophenones were also supplied by Sigma Aldrich (St. Louis, MO, USA), Serva Electrophoresis GmbH (Heidelberg, Germany), Fisher Sciencetific (Loughborough, UK), Acros Organics (Branchburg, NJ, USA); and used directly without further purification.…”

An Update of the Use of Thiocarbohydrazides and Thiosemicarbazides in the Preparation of Heterocycles and Their Biological Importance

“…By both traditional (stirring at r.t) and microwave‐assisted procedures, aryl thiosemicarbazides 53a–d or alkyl thiosemicarbazides 54e–i were obtained from the reaction of alkyl or aryl isothiocyanate 52a – i with hydrazine hydrate or phenyl hydrazine in toluene (Scheme ) .…”