2-Butenoic acid, 3-amino-, 1-methylethyl ester → Isradipine

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Dissolved the purified 2-acetyl-3-benzofurazan-4-yl-acrylic acid methyl ester obtained in example—3 (25 g, 0.10 mol) in absolute ethanol (375 ml) and added in to the solution isopropyl-β-aminocrotonate (13.15 ml, 0.09 mol). Stirred the reaction mixture under nitrogen atmosphere at 25-28° C. for 5 hr. Removed sample from the reaction mixture and analysed the sample by qualitative HPLC. Distilled ethanol from the reaction mixture under vacuum at 50° C. Dissolved the residue in ethyl acetate (235 ml) and washed twice with water (90 ml). Dried the organic layer over sodium sulphate and distillation under vacuum at 50° C. Dissolved the concentrate in ethanol (65 ml at 70° C. and slowly cooled to 5° C. to get the product crystallised. Filtered the product and washed with pre cooled ethanol (25 ml and dried at 70° C. under vacuum to obtain 30 g Isradipine (purity=99.4%, Impurity III=0.22%, and Impurity IV=0.11% by HPLC.

Herkunft & Nachweise