CONFORMATIONAL FLEXIBILITY OF THE 1,4-DIHYDROPYRIDINE RING IN CALCIUM-CHANNEL AGONISTS AND ANTAGONISTS MOLECULES

Conformational flexibility of the 1,4-dihydropyridine ring in 4-aryl d erivatives of the 2,6-dimethyl-3,5-dicarbmethoxy-1,4-dihydropyridine h as been studied using the MM3 molecular mechanics method. Change of th e C=C-C-C= endocyclic torsion angle of dihydrocycle in the range of 35 degrees entails an increase of energy less than 1 kcal mol(-1). The e nergy levels below 99% of the molecular population for each molecule w ere estimated. The interval of the torsion angle change for these regi ons is about 60 degrees.