The effect of ortho methyl groups on the methylsulphonyl group, compared with their influence on the nitro group: (Properties of the sulphonyl group XXXIII

Abstract

Abstract 4‐Methylsulphonyl‐3,5‐xylenol has been prepared by a series of reactions involving thiocyanation, reduction with LiAlH 4 , methylation, and oxidation. The methylsulphonyl group exerts a negative mesomeric effect, which, however, is not hindered by ortho methyl groups. The spectrum as well as the ionization constant prove this. For the latter property, additivity of Hammett's σ‐constants for groups in the 3, 4, and 5 positions was taken as a criterion. For sulphur, as a second‐row element, coplanarity of its SO‐valencies and the benzene nucleus is no condition for maximum resonance. Throughout this paper, the data of the corresponding nitro compounds have been measured for comparison.