The conformational features of three tetrahydropyridinyl oxime cognition activators 1-(1-methyl-1,2,5,6-tetrahydro-3-pyridinyl)ethanone oxime.HCl (I), 1-(1-methyl-1,2,3,6-tetrahydro-4-pyridinyl)ethanone oxime.HCl (II), and 1-(1,2,5,6-tetrahydro-3-pyridinyl)ethanone O-methyloxime HCl(III) were analyzed by X-ray diffraction and the quantum mechanical semiempirical PM3 methods. Results indicate that in the solid state the drugs exhibit "anti-syn" isomerism, with the substituent at the oxime oxygen atom anti oriented in respect to C = N. This arrangement also represents a low-energy situation in vacuo, as confirmed at the PM3 level, although another low-energy conformation ("clinal-anti") could be of significance in the conformational energetics of the drugs.
Conformation of three tetrahydropyridinyl oxime cognition activators
BANDOLI, GIULIANO;DOLMELLA, ALESSANDRO;NICOLINI, MARINO;
1991
Abstract
The conformational features of three tetrahydropyridinyl oxime cognition activators 1-(1-methyl-1,2,5,6-tetrahydro-3-pyridinyl)ethanone oxime.HCl (I), 1-(1-methyl-1,2,3,6-tetrahydro-4-pyridinyl)ethanone oxime.HCl (II), and 1-(1,2,5,6-tetrahydro-3-pyridinyl)ethanone O-methyloxime HCl(III) were analyzed by X-ray diffraction and the quantum mechanical semiempirical PM3 methods. Results indicate that in the solid state the drugs exhibit "anti-syn" isomerism, with the substituent at the oxime oxygen atom anti oriented in respect to C = N. This arrangement also represents a low-energy situation in vacuo, as confirmed at the PM3 level, although another low-energy conformation ("clinal-anti") could be of significance in the conformational energetics of the drugs.Pubblicazioni consigliate
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