Intramolecular Nonbonded S···O Interaction Recognized in (Acylimino)thiadiazoline Derivatives as Angiotensin II Receptor Antagonists and Related Compounds

The intramolecular nonbonded 1,5-type S···O interactions are recognized in the crystalline structures of the (acylimino)thiadiazoline derivatives ( 1 − 3 ) as angiotensin II receptor antagonists. The relative stability of the nonbonded 1,5-type S···O interaction was investigated using the X-ray crystallographic analyses and the ab initio MO calculations (HF/3-21G*, 6-31G*, and 6-311+G**) of the simplified model compounds ( 6, 7, and 9 ). The concept of mimic-fused bicyclic heterocycles consisting of fairly stable nonbonded S···O interaction seems to be an efficient approach toward the design and development of various drugs.