反应详情

In the first step of the synthesis 2-nitro-benzaldehyde is reacted with methyl acetoacetate in the presence of a catalytic amount (0.01-0.7 mole, related to 1 mole of methyl acetoacetate) of piperidine acetate to give methyl-2-nitro-benzylidene-acetoacetate with a high yield of about 97%. This product is reacted after or without isolation with methyl-3-amino-crotonate. The yield of the second step is 87%, the total yield of both steps amounts to 84.4%. According to the disclosure of the cited Hungarian patent the thin layer chromatogram of the nifedipine thus obtained shows no by-products (Merck-type plate coated with kieselgel; developed with a 3:2:5 mixture of chloroform, acetone and petrolether).