SUMMARYThe N.M.R. spectra of five pairs of 4 alkoxy-a, p-dialkylstyrenes of known configuration (general formulae XI and XII) are compared and a set of ru!es suitable for geometric configuration assignmmt in such compounds is deduced:1 . The strong signals in the aromatic AaBz methoxystyrene system are 25-30 CIS apart in the cis isomer and only 13-16 c/s in the trans isomer.2. The olefinic and allylic protons signals are shifted 7-20 c/s downfield in the cis isomer.The origin of the observed shifts is discussed. The configuration of ten new styrene compounds is elucidated by application of these rules.

PRfiPARATION DE STYRENES a, p DISUBSTITU6S M. BARBIEUX et R.H. MARTIN (Bruxelles) SUMMARYSeveral mixtures of unsaturated esters were obtained by dehydration of hydroxyesters (Io --f Ih) (from a Reformatsky reaction) and each constituent, after separation by gas liquid chromatography, was assigned either the a,

No abstract