Reactions of pyrazoles and pyrazolium salts with complex metal hydrides and organometallic reagents. Synthesis of pyrazolines and pyrazolidines

✍ Scribed by Purificación Cuadrado; Ana M. González-Nogal; Senén Martínez

• Book ID: 104207864
• Publisher: Elsevier Science
• Year: 1997
• Tongue: French
• Weight: 827 KB
• Volume: 53
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(97)00514-0

✦ Synopsis

2-Pyrazolin-4-oximes have been synthesized by reaction of 4-nitroso-and 4nitropyrazoles with complex metal hydrides and organometallic reagents. Furthermore, 4nitropyrazolium tetrafluoroborates are reactive substrates towards organolithium and Grignard compounds leading to new and highly substituted 4-nitro-3-pyrazolines and 4nitropyrazolidines. The formation of 3-pyrazolines is regioselective and, when diastereoisomer pyrazolidines are possible, only the most stable 3,4-trans and/or 4,5trans isomers were obtained.