Proton magnetic resonance spectral line widths and splittings for tertiary methyl groups

✍ Scribed by M.J.T. Robinson

• Book ID: 104223250
• Publisher: Elsevier Science
• Year: 1965
• Tongue: French
• Weight: 308 KB
• Volume: 6
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)90110-2

✦ Synopsis

The recent communicot'ons (1,2) about proton magnetic resonance (PMR) spectral line widths (width at half-height, w 1 ) and plittings in several steroids prompts me to report and comment on measurements on simpler compounds with tertiary methyl groups. Because the resolution of spectrometers vory from time to time the observed line widths ore not constant for any given compound but the difference, Aw 4, between the line widths for a methyl group and for tetramethylsilane (w I! varied from 0.4 to 0.7 cps in the measurements described here) in the same solution should be more nearly constant: this was tested explicitly for IO-methyl-cis-2-decolone and Aw for the f methyl group in this compound was found to be constant to within 0.1 cps when w B for tetromethylsilone varied from 0.4 to 1.0 cps.

In comparable pairs of derivatives of G-and trans-9-methyldecalin

Awh for the angular methyl groups is regularly greater for the trons than for the cis isomers -(Table l), and similar differences ore found in the pairs of octahydrophenanthrenes IV and benzhydrindanes V.