Zsila F, Hollósi M, Gergely A. Stereochemical study of tolperisone, a muscle relaxant agent, by circular dichroism and ultraviolet spectroscopy.
Chirality 2000;
12:720-6. [PMID:
11054830 DOI:
10.1002/1520-636x(2000)12:10<720::aid-chir4>3.0.co;2-2]
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Abstract
The stereochemistry of tolperisone, a chiral aryl-alkyl basic ketone was investigated by means of circular dichroism (CD) and ultraviolet (UV) spectroscopy. The unusually high optical activity of tolperisone hydrochloride in the n-->pi* region is interpreted by the presence of a chiral conformer in solution. For stereochemical reasons, the C = O group and the aromatic moiety lack coplanarity by forming an inherently dissymetric chromophore, of M helicity. Similar helicity prevails in the crystal phase, according to the solid-state CD spectrum of (-)-tolperisone HCl salt. The chirality rule proposed by Snatzke for nonplanar benzoyl chromophores predicts the absolute configuration of (-)-tolperisone hydrochloride to be R, in agreement with other alpha-methyl-beta-amino-ketones.
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