Unusual effects of steric hindrances in NMR spectra of o,o′-dialkylsubstituted benzylidene dichlorides
作者:A.P. Yakubov、D.V. Tsyganov、L.I. Belen'kii、V.S. Bogdanov、B.I. Ugrak、M.M. Krayushkin
DOI:10.1016/s0040-4020(01)87135-0
日期:1991.1
It has been found that steric hindrances of the CHCl2 group rotation around C(Ar)-CHCl2 bond in o,o'-dialkylsubstituted benzylidene dichlorides call forth a non-equivalence of the alkyls in positions 2 and 6. The non-equivalence displays in H-1 and C-13 NMR spectra at room temperature and at -20 degrees-C. At the latter temperature, the spectra of 2,4,6-trimethyl-3-chloromethylbenzylidene dichloride and bis(dichloromethyl)mesitylene indicate the presence of two conformations, the assignment of signals having been accomplished for each of them.