A multicomponent reaction (MCR) strategy, alternative to the known cycloaddition reaction, towards variously substituted 1-amino-1H-imidazole-2(3H)-thione derivatives has been successfully developed. The novel approach involves -halohydrazones whose azidation process followed by tandem Staudinger/aza-Wittig reaction with CS2 in a sequentialMCRregioselectively leads to the target compounds avoiding the formation of the regioisomer iminothiazoline heterocycle. The approach can be applied to a range of differently substituted alpha-halohydrazones bearing also electron-withdrawing groups confirming the wide scope and the substituent tolerance of the process for the synthesis of the target compounds. Interestingly, the concurrent presence of reactive functionalities in the scaffolds so obtained ensures post-modifications in view of N-bridgeheaded heterobicyclic structures.

Sequential MCR via Staudinger/Aza-Wittig versus Cycloaddition Reaction to Access Diversely Functionalized 1-Amino-1H-Imidazole-2(3H)-Thiones

Cecilia Ciccolini;Giacomo Mari;Gianfranco Favi;Fabio Mantellini;Lucia De Crescentini;Stefania Santeusanio
2019

Abstract

A multicomponent reaction (MCR) strategy, alternative to the known cycloaddition reaction, towards variously substituted 1-amino-1H-imidazole-2(3H)-thione derivatives has been successfully developed. The novel approach involves -halohydrazones whose azidation process followed by tandem Staudinger/aza-Wittig reaction with CS2 in a sequentialMCRregioselectively leads to the target compounds avoiding the formation of the regioisomer iminothiazoline heterocycle. The approach can be applied to a range of differently substituted alpha-halohydrazones bearing also electron-withdrawing groups confirming the wide scope and the substituent tolerance of the process for the synthesis of the target compounds. Interestingly, the concurrent presence of reactive functionalities in the scaffolds so obtained ensures post-modifications in view of N-bridgeheaded heterobicyclic structures.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11576/2671480
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