Halogeno-1,4-dioxans and their derivatives. Part VII. Conformations and 1H nuclear magnetic resonance parameters of some chloro-1,4-dioxans and 5-chloro-2,3-dihydro-1,4-dioxin

Abstract

¹ H N.m.r. parameters have been obtained for 5-chloro-2,3-dihydro-1,4-dioxin, and for 2-chloro-, 2,2-dichloro-, 2,2,3-trichloro-, and for two 2,3,5,6-tetrachloro-1,4-dioxans of m.p.s 142 and 70°; some anomalies are observed regarding long range shielding by chlorine. The fourth and sixth of these have rigid conformations, that of the last being in agreement with previous findings for the solid. New preparations of 4,4′,5,5′-tetrachlorobi-1,3-dioxolan-2-yl from a di- and a tetra-chloro-1,4-dioxan are reported.