PMR studies of N-substituted-2,5-dimethyl-4-piperidones

✍ Scribed by M. M. A. Hassan; A. F. Casy

• Publisher: John Wiley and Sons
• Year: 1970
• Tongue: English
• Weight: 561 KB
• Volume: 2
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1270020213

✦ Synopsis

Abstract

PMR characteristics of some isomeric 1‐substituted‐2,5‐dimethyl‐4‐piperidones are reported and major isomers shown to have a trans 2,5‐dimethyl configuration. Differences between benzylic methylene signals of isomeric 1‐benzyl analogs provide evidence of the preferred conformation of the cis derivative. Evidence of the D/H exchange of α‐protons in 1,2,5‐trimethyl‐4‐piperidone base and of addition of D~2~O to the carbonyl group of the corresponding hydrochloride and methiodide salts is also demonstrated. The effect of a 2‐methyl substituent upon the chemical shifts of N‐methyl groups in some piperidine methiodides is discussed.