反应详情

20.5 g of 2-nitratopropyl acetoacetate, 15.1 g of 3-nitrobenzaldehyde and 1.5 g of piperidine acetate in 74 ml of benzene were heated at reflux under azeotropic dehydration conditions for 2 hours. The reaction solution was washed, in turn, with 25 ml of water, 25 ml of an aqueous 1N sodium bisulfite solution and 25 ml of water and dried over anhydrous sodium sulfate, and the benzene was evaporated under reduced pressure. To the residue thus obtained was added 15.4 g of 2-cyanoethyl 3-aminocrotonate, and the mixture was taken up in 44 ml of isopropyl alcohol, heated at reflux for 3 hours and cooled on ice. The crystals which precipitated were collected by filtration, dried, applied to a silica gel column chromatography [eluent: a mixture of hexane and ethyl acetate (1:1)] and recrystallized from isopropyl alcohol to give 31.2 g of 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-(2-cyanoethyl) ester 5-(2-nitratopropyl) ester.

1. temperatureat reflux under azeotropic dehydration conditions for 2 hours
2. washThe reaction solution was washed, in turn, with 25 ml of water, 25 ml of an aqueous 1N sodium bisulfite solution and 25 ml of water
3. dry with materialdried over anhydrous sodium sulfate
4. customthe benzene was evaporated under reduced pressure
5. customTo the residue thus obtained
6. temperatureheated
7. temperatureat reflux for 3 hours
8. temperaturecooled on ice
9. customThe crystals which precipitated
10. filtrationwere collected by filtration
11. customdried
12. additiona mixture of hexane and ethyl acetate (1:1)] and
13. customrecrystallized from isopropyl alcohol