Solvent effects in N.M.R. spectroscopy. I. Chemical shifts induced by benzene in some steroidal ketones and acetates

✍ Scribed by Norman S. Bhacca; Dudley H. Williams

• Publisher: Elsevier Science
• Year: 1964
• Tongue: French
• Weight: 254 KB
• Volume: 5
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)89433-8

✦ Synopsis

The C-18 and C-19 methyl resonances of 5a-androstane occur at s = 0.69 p.p.m. and 6~0.79 p.p.m. in deuteriochloroform solution (I) and at dzO.71 p.p.m. and 6=0.79 p.p.m. in benzene solution .* It therefore appears likely that in the absence of polar functional groups, no preferred geometrical relationship exists between solvent and solute molecules, since the position of the angular methyl rescnances ore barely influenced on passing from deuteriochloroform to benzene as solvent. However, the positions of the C-18 and C-19 angular methyl resonances in the n.m.r. spectm of Sa-androstan-l-one, %r-androstan-2-one, and So, 14@-androstcn-15 one (I) and Saandrostun-II-one (II) are considerably different in deuteriochloroform and benzene solutions. The data are summarized in Table I; the calculated positions of the COIC. angular methyl rescmances in deuteriochloroform solution (6 CDC, ) were obtained by 3 using the table of additive shifts compiled by Z&her (I). *All n.m.r. spectra discussed 'n this paper were determined on Varian A-60 or HR-100 spectrometers.