Cytotoxic compounds. Part XII. Some 3-arylthiopropane-1,2-diols and 2-arylthiopropane-1,3-diols. Rearrangement of the 1,3-dimethanesulphonates to the 1,2-isomers

Abstract

Syntheses of the title diols, their acetates, and their methyl ethers are described, where the aryl group is p-chloro-p-methoxy-, p-methylthio-, and 2,4-dinitro-phenyl. Rearrangement through an episulphonium ion-pair occurs in the preparation of a dimethanesulphonate from 2-(p-methoxyphenylthio)propane-1,3-diol, the product being the derivative of the isomeric 1,2-diol. Unrearranged dimethanesulphonates were obtained from all the other diols, but the 1,3-dimethanesulphonates where the aryl group is phenyl, p-chlorophenyl, and p-methylthiophenyl undergo rearrangement to the 1,2-isomers in boiling acetone. In methanol, solvolysis of the 1,3-dimethanesulphonates occurs much more rapidly than with the 1,2 isomers.

The two geometrical isomers of the O-toluene-p-sulphonate of 1,3-O-benzylideneglycerol have been separated and identified. Some of the aryl sulphides, obtained by displacement reactions on this sulphonte with aryl thiols, have also been obtained as individual stereoisomers.

The ¹H n.m.r. spectra of the diols and of their derivatives are tabulated.