A quantum chemical study with special reference to the sulfamyl group of sulfonylureas

HUCKEL's LCAO-MO Method was applied to the sulfamyl part of sulfonylureas and related compounds. The parameters used were already discussed in the authors' previous report. |K| values of the lowest vacant energy level of sulfonylureas were less than those of DPN. Such characteristic nature of the compounds seems to unrelated to their hypoglycemic activity. Hypoglycemic activity, seems to depend on the structural specificity of the nucleophilic reaction site of oxygen symmetrically and the electrophilic reaction site of the sulfur in the sulfamyl part between banzene and the urea portion. Moreover, a specific electronic environment required for the urea portion of sulfonylureas was pointed out as essential nature. A continuous π-electron bonded structure from benzene to the sulfamyl part and to the urea portion seems to be indispensable in enhancing water permeability of the toad bladder. The quantum chemical significance of R and R' portion was discussed.