Abstract
The conformation of semotiadil (1) was investigated by the molecular mechanics method. The analysis of energy components of the stable conformations suggested that stabilities are principally under the control of van der Waals and torsional energy terms. Two major van der Waals interactions were found between the 2-phenyl and the methylene-dioxyphenyl rings, and between the alkylamine side chain and the benzothiazine ring. The torsional energy term was caused mainly by the alkylamino side chain conformation. Stable conformations would be useful when considering possible solution conformations of 1.
