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Hetarylnitrenes V. Reactions of Tetrazolopyrazine Ring Contraction of Nitrenodiazines in Solution. Preliminary communication

✍ Scribed by Curt Wentrup

Book ID
102249406
Publisher
John Wiley and Sons
Year
1972
Tongue
German
Weight
275 KB
Volume
55
Category
Article
ISSN
0018-019X

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✦ Synopsis

Abstract

Thermolysis of tetrazolopyrazine (1) in organic solvents gives pyrazinylnitrene (2) which undergoes ring contraction to 1‐cyanoimidazole (3). 7‐Methyl‐5‐methylthio‐tetrazolo[1,5‐c]pyrimidine (4) likewise gives 1‐cyano‐2‐methylthio‐4‐methyl‐imidazole (6). The two tetrazoles also undergo ring contraction to 1‐cyanoimidazoles by gas chromatography, and 1 gives a low yield of 3 by photolysis. Thermolysis of 1 and 4 in cyclohexane gives aminopyrazine (7) and 6‐amino‐4‐methyl‐2‐methylthio‐pyrimidine (8), respectively. Tetrazolo[1,5‐a]pyrimidines (9) give only 2‐aminopyrimidines (10).

1‐Cyanoimidazole, formed by thermolysis of 1 in acetic acid, reacts further to give 1‐acetylimidazole, which with more acetic acid gives imidazole and acetic anhydride. An earlier report [2] of ring expansion of pyrazinylnitrene in acetic acid is discredited.

In protic deuteriated solvents (D~3~O, CH~3~OD), tetrazolopyrazine reacts as an enamine, specifically exchanging HC(6) for deuterium.

📜 SIMILAR VOLUMES

The Ring Expansion - Ring Contraction Di
The Ring Expansion - Ring Contraction Dichotomy in Aromatic Nitrene and Carbene Reactions II. Hetarylnitrenes. Preliminary communication
✍ C. Wentrup; C. Thétaz; R. Gleiter 📂 Article 📅 1972 🏛 John Wiley and Sons 🌐 German ⚖ 260 KB

## Abstract ^15^N‐labelling experiments and energy calculations on nitreno‐azines and ‐diazies are in agreement and lead to the theory that both ring contraction and ring expansion in hetarylnitrenes __can__ be one‐step processes which are governed mainly by the energy differences between the react