v-Triazolines, XXIV. Pyrazolecarbaldehydes from 5-Amino-4,5-dihydro-4-methylene-v-triazoles and Sydnones

✍ Scribed by Destro, Riccardo ;Erba, Emanuela ;Forti, Luciana ;Pocar, Donato ;Scarcella, Daniela

• Book ID: 102901422
• Publisher: John Wiley and Sons
• Year: 1985
• Tongue: English
• Weight: 624 KB
• Volume: 1985
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.198519850709

✦ Synopsis

Abstract

The sydnones 1a–c react with the 4,5‐dihydro‐v‐triazoles 2a–c by long refluxing at 110– 140°C affording via non‐isolable adducts with elimination of CO~2~ and N~2~ and rearrangement a mixture of 4,5‐dihydropyrazoles 3a– c, 3‐pyrazolecarbaldehyde anils 4a–d, and 3‐pyrazolecarbaldehydes 5a–c. Compounds 3 can be deaminated to give 4 which can be hydrolyzed to yield the 3‐pyrazolecarbaldehydes 5.– The sydnones 6a, b react similarly with 2a to give a mixture of 4‐pyrazolecarbaldehyde anils 7a, b and 4‐pyrazolecarbaldehydes 8a, b. The structural assignments are based on spectroscopic and X‐ray diffraction data.