Enantioselective synthesis and pharmacological evaluation of a new type of verapamil analog with hypotensive and calcium antagonist activities

Article abstract of DOI:10.1023/A:1018888711071

Purpose. The syntheses and evaluation for cardiovascular activity in the rat of both enantiomers of a verapamil analog in which the cyano group has been replaced by hydroxyl. Methods. (+)- and (-)-α-[3-[[2-(3,4- Dimethoxyphenyl)ethyl]methylamino]propyl]-3,4-dimethoxy-α-(1-methyl ethyl)benzyl alcohol were prepared from chiral sulfoxides produced by microbial biotransformations using Mortierella isabellina ATCC 42613 or Helminthsporium Species NRRL 4671, and were examined for hypotensive and calcium antagonist activity using anaesthetized normotensive rats and isolated rat aorta and atria. Results. The analogs showed a pharmacological profile similar to that exhibited by verapamil, possessing a remarkable hypotensive activity, accompanied by a significant bradycardia, in anaesthetized normotensive rats. In vitro, these analogs displayed clear inhibitory effects: in isolated rat aorta they inhibited, in a concentration- dependent fashion, the contractions and ⁴⁵Ca²⁺ uptake induced by norepinephrine and high KCl, and in isolated rat atria the analogs considerably decreased the rate of contraction (negative chronotropic effects). No significant differences between the quantitative cardiovascular effects produced by the two enantiomers of the verapamil analogs were observed. Conclusions. The results suggest that, like that of verapamil, the cardiovascular activity exhibited by the new compounds seems to be due, at least in part, to a blockage of transmembrane calcium channels present in vascular smooth muscle cells.