The Crystal Structure of Lacidipine Phototransformation Product

Diethyl (E)-4-{2-{2-(tert-butoxycarbonyl)vinyl}phenyl}-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate or lacidipine (1) is a drug used for treatment of hypertension. The literature data for the undesired daylight phototransformation of compound 1 was confirmed for UV light as well. The main product, (1 alfa,1a alfa,4a alfa,8b alfa,8c alfa) 1-(1,1-dimethylethyl) 4,8c-diethyl 1a,2,4a,8b-tetrahydro-1a,3-dimethyl-2-azacyclobuta{jk}fluorene-1,4,8c(1H)-tricarboxylate was isolated and the crystal structure was determined.