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Efficient synthesis of tri- and difluoroacetyl hydrazides as useful building blocks for non-symmetrically substituted, fluoroalkylated 1,3,4-oxadiazoles


Mloston, Grzegorz; Obijalska, Emilia; Zurawik, Alicja; Heimgartner, Heinz (2016). Efficient synthesis of tri- and difluoroacetyl hydrazides as useful building blocks for non-symmetrically substituted, fluoroalkylated 1,3,4-oxadiazoles. Chemistry of Heterocyclic Compounds, 52(2):133-139.

Abstract

A convenient and efficient approach to 2-arylamino-5-fluoroalkyl-1,3,4-oxadiazoles has been established via heterocyclization of tri- and difluoroacetylated thiosemicarbazides using dicyclohexylcarbodiimide. A heterocyclization performed with selected thiosemicarbazides under basic conditions led to 4-aryl-5-fluoroalkyl-2,4-dihydro-3H-1,2,4-triazole-3-thiones in moderate yields. The starting fluoroacetylated thiosemicarbazides were prepared by fluoroacetylation of benzyloxycarbonyl-protected hydrazine with a corresponding anhydride, followed by hydrogenolytic deprotection and reaction with arylisothiocyanates. Fluoroacetylated semicarbazides were prepared similarly, but all attempts to achieve their heterocyclization were unsuccessful.

Abstract

A convenient and efficient approach to 2-arylamino-5-fluoroalkyl-1,3,4-oxadiazoles has been established via heterocyclization of tri- and difluoroacetylated thiosemicarbazides using dicyclohexylcarbodiimide. A heterocyclization performed with selected thiosemicarbazides under basic conditions led to 4-aryl-5-fluoroalkyl-2,4-dihydro-3H-1,2,4-triazole-3-thiones in moderate yields. The starting fluoroacetylated thiosemicarbazides were prepared by fluoroacetylation of benzyloxycarbonyl-protected hydrazine with a corresponding anhydride, followed by hydrogenolytic deprotection and reaction with arylisothiocyanates. Fluoroacetylated semicarbazides were prepared similarly, but all attempts to achieve their heterocyclization were unsuccessful.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
Dewey Decimal Classification:540 Chemistry
Language:English
Date:March 2016
Deposited On:17 Mar 2016 07:05
Last Modified:01 Mar 2017 01:00
Publisher:Wiley-Blackwell Publishing, Inc.
ISSN:0069-3154
Funders:National Science Center (Cracow, PL), Grant: OPUS-7 (2014/13/B/ST5/04004)

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