4-[(1,1-Dioxo-1lambda~6~,4-thiazinan-4-yl)-methyl]benzenecarboxylic acid4-[(1,1-dioxo-1lambda~6~,4-thiazinan-4-yl)methyl]benzenecarboxylic acid4-(4'-Carboxybenzyl)thiomorpholine 1,1-dioxide4-(4-Carboxybenzyl)thiomorpholine 1,1-dioxide4-[(1,1-Dioxidothiomorpholin-4-yl)methyl]benzoic acid