摘要 |
<p>Method comprises reacting m-nitrobenzaldehyde with acetoacetic acid ester (II) and 3-amino-crotonic, acid ester of the crotonic ester, so that 2 moles of water are formed on reacting one mole of each reactant, to form a dihydro pyridine ring. The water is removed by azeotropic distillation to give cpd. (I). R1 is 1-4C alkyl or 1-5C methodxyalkyl and R2 is 1-4C alkyl. (I) is 1,4-dihydro-2,6 dimethyl-4-(3-nitrophenyl) 3,5-pyrindine carboxylic acid ester.</p> |