Acetic Acid → HCID 54357565, compound

Participants

Reaction Steps

To a solution of 3-nitrobenzaldehyde (4.53 g), 2-benzyloxyethyl acetoacetate (7.79 g) and acetic acid (360 mg) in benzene (15 ml), was added a solution of piperidine (306 mg) in benzene (5 ml), in a similar manner to the aforementioned Example 1-i), and the mixture was heated to reflux for 2.5 hours under azeotropic dehydration. The reaction mixture was left to cool and diluted with benzene (50 ml), washed with water, diluted aqueous sodium bicarbonate solution and water, dried over magnesium sulfate and then evaporated to dryness under reduced pressure to give brown oily 2-benzyloxyethyl 2-(3-nitrobenzylidene)-acetoacetate (12.58 g). The mixture of the above obtained oil (12.58 g) and ethyl 3-amino-4,4-diethoxycrotonate (8.47 g) was heated at 100° to 102° C. for 4 hours and at 110° to 115° C. for 6.5 hours. After cooling, the reaction mixture was dissolved in ethyl acetate, washed twice with water and saturated aqueous sodium chloride solution, dried over magnesium sulfate and evaporated to dryness under reduced pressure. The residual brown oil (19.04 g) was chromatographed on a column of silica-gel (570 g) and eluted with a mixture of benzene and ethyl acetate (13:1, v/v) to give oily 2-benzyloxyethyl 2-methyl-4-(3-nitrophenyl)-5-ethoxycarbonyl-6-diethoxymethyl-1,4-dihydropyridine-3-carboxylate (9.64 g).

Provenance & Evidence