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C-Glycosides VI. Modalités de l'élaboration de cycles pyrazoliques à partir d'une hydrazone d'aldéhydo-sucre

✍ Scribed by J. M. J. Tronchet; A. Jotterand

Publisher
John Wiley and Sons
Year
1971
Tongue
German
Weight
874 KB
Volume
54
Category
Article
ISSN
0018-019X

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✦ Synopsis

Abstract

The reaction of an aldehydo‐sugar hydrazonoyl bromide with ethynylmagnesium bromide led mainly to an α‐ethynyl‐hydrazone whose cyclisation to a pyrazole is catalysed by bases. Thus the nucleophilic substitution – nucleophilic cyclisation mechanism of the __Grünanger__pyrazole synthesis is confirmed. 3‐Glycosyl‐pyrazoles can also be prepared from aldehydo‐sugar hydrazonoyl bromides by 1,3‐dipolar cyclo‐addition. All these reactions take place without change in the configuration of the initial aldehydo‐sugar.

📜 SIMILAR VOLUMES

Dérivés C-glycosyliques VIII. Synthèse d
Dérivés C-glycosyliques VIII. Synthèse de C-glycosyl-3-pyrazoles à partir d'une nitrilimine dérivée de l'anhydro-2,5-D-ribose. Compétition entre cyclo-additions dipolaires-1,3 et cyclisations non concertés
✍ J. M. J. Tronchet; Melle F. Perret 📂 Article 📅 1972 🏛 John Wiley and Sons 🌐 German ⚖ 835 KB

## Abstract Several 3‐(2,5‐anhydro‐ribosyl)‐pyrazoles of potential medicinal interest have been synthesized by reacting alkynes or alkynylmagnesium bromides with the __p__‐nitrophenylhydrazone of 2,5‐anhydro‐ribonyl bromide. From a mechanistic standpoint, it has been shown that the sugar‐nitrilimin