Conformational Studies of Semotiadil (SD-3211), a Novel Ca2+ Antagonist

Autor:	Yoichi Kawashima, Atsutoshi Ota, Toshimasa Ishida, Hirofumi Ohishi
Rok vydání:	1993
Předmět:	Hydrogen bond Stereochemistry Diastereomer Absolute configuration General Chemistry General Medicine Crystal structure Chromophore Benzothiazine Mandelic acid Ring (chemistry) chemistry.chemical_compound Crystallography chemistry Drug Discovery
Zdroj:	Chemical and Pharmaceutical Bulletin. 41:1681-1685
ISSN:	1347-5223 0009-2363
DOI:	10.1248/cpb.41.1681
Popis:	The stereochemistry of a novel Ca2+ antagonist, semotiadil, 1, was investigated using X-ray crystallography and CD. The X-ray structure was analyzed using its diastereomeric salt with (S)-(+)-mandelic acid (2); 1 (mandelate). The R absolute configuration of 1, which was previously determined by chemical transformation of the optically-active synthetic precursor, was directly confirmed by this analysis. The hydrogen bonding, electrostatic and the hydrophobic interactions, which stabilize the crystal structure, were observed in the crystal. CD spectra of 1 (mandelate) and the hydrogen fumarate of 1 (SD-3211; 1 (fumarate)) in ethanolic solution exhibited similar spectral patterns. The CD bands from each chromophore were unambiguously assigned and the conformation of the benzothiazine ring was determined using the helicity rule. The X-ray and CD data confirmed the P-conformation of the benzothiazine ring and the existence of the 2-phenyl ring in an equatorial position in both of the crystal and ethanolic solution states. These findings were in good agreement with our previous results regarding the conformational analysis of 2-arylbenzothiazine derivatives.
Databáze:	OpenAIRE
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