A Synthetic and Stereochemical Study of 2,6-Diaroyl-3,5-Diaryl-4-Ethyltetrahydro-1,4-Thiazine-1,1-Dioxides

Double aza-Michael addition of ethylamine over 2,2'-sulfonylbis(1,3-diarylprop-2-en-1-ones) gave the previously unknown title compounds in moderate yields. The decreased yields of the title compounds compared to 2,6-diaroyl-3,5-diaryltetrahydro-1,4-thiazine-1,1-dioxides or the corresponding 4-methyl derivatives is explained on the basis of steric size of the nucleophile. The structure and stereochemistry of the thianes have been deduced from elemental analyses and spectroscopic data.