Synthesis of Clevidipine Butyrate

Clevidipine butyrate,an antihypertensive agent,was synthesized from 2-cyanoethyl acetoacetate(2), 2,3-dichlorobenzaldehyde and methyl 3-aminocrotonate by Hantzsch cyclocondensation and followed by selective hydrolysis with sodium sulfide at room temperature to give 4-(2,3-dichlorophenyl)-1,4-dihydro-2,6-dimethy1-3,5- pyridinedicarboxylic acid monomethyl ester,which was then subjected to reaction with chloromethyl butyrate with an overall yield of about 59%(based on 2).