Synthesis 2017; 49(10): 2129-2137
DOI: 10.1055/s-0036-1588774
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© Georg Thieme Verlag Stuttgart · New York

First (3+2)-Cycloadditions of Thiochalcones as C=S Dipolarophiles: Efficient Synthesis of 1,3,4-Thiadiazoles via Reactions with Fluorinated Nitrile Imines

Paulina Grzelak
,
Greta Utecht
,
Marcin Jasiński
,
Grzegorz Mlostoń*
Supported by: National Science Center (Cracow, Poland),
Supported by: Grant / Award Number: '2012/06A/ST5/00219', '2014/13/B/ST5/04004'
Further Information

Publication History

Received: 01 February 2017

Accepted after revision: 13 March 2017

Publication Date:
11 April 2017 (online)


Dedicated to Professor Sławomir Jarosz (Warsaw) on the occasion of his 65th birthday

Abstract

Fluorinated nitrile imines generated in situ from the corresponding fluoral-derived hydrazonoyl bromides smoothly react with monomeric aryl/hetaryl-substituted thiochalcones yielding 2,3-dihydro-1,3,4-thiadiazoles in a chemo- and regioselective manner. The elaborated protocol can be efficiently applied starting with precursors functionalized with both electron-donating and electron-withdrawing groups located at the para position of the aryl ring. In contrast, the non-fluorinated nitrile imines do not enter the (3+2)-cycloaddition reactions with title thiochalcones.

Supporting Information