2-Methoxybenzaldehyde → Ethyl 2-(2-methoxybenzylidene)4,4-diethoxyacetoacetate

Reaktionsgleichung

[CH3:1][O:2][C:3]1[CH:10]=[CH:9][CH:8]=[CH:7][C:4]=1[CH:5]=O.[CH2:11]([O:13][CH:14]([O:23][CH2:24][CH3:25])[C:15](=[O:22])[CH2:16][C:17]([O:19][CH2:20][CH3:21])=[O:18])[CH3:12]>N1CCCCC1.C1C=CC=CC=1>[CH3:1][O:2][C:3]1[CH:10]=[CH:9][CH:8]=[CH:7][C:4]=1[CH:5]=[C:16]([C:15]([CH:14]([O:13][CH2:11][CH3:12])[O:23][CH2:24][CH3:25])=[O:22])[C:17]([O:19][CH2:20][CH3:21])=[O:18]

Komponenten

Versuchsvorschrift

A solution of 2-methoxybenzaldehyde (2.7228 g), ethyl 4,4-diethoxyacetoacetate (4.3648 g) and piperidine (4 or 5 drops) in benzene (20 ml) was refluxed under azeotropic dehydration for 3 hours. The resultant solution was washed with water and dried. The solvent was removed from the extract to give oily ethyl 2-(2-methoxybenzylidene)-4,4-diethoxyacetoacetate. The mixture of the compound obtained above and ethyl 3-aminocrotonate (2.5832 g) was heated in an oil bath (about 100° C.) for 7 hours. After cooling, the reaction mixture was extracted with diethyl ether, and the extract was washed with water twice and dried over magnesium sulfate. The solvent was removed to give a red oil. The oil was purified by a column chromatography on silica gel with an eluent (benzene:ethyl acetate=20:1) to give diethyl 2-methyl-4-(2-methoxyphenyl)-6-diethoxymethyl-1,4-dihydropyridine-3,5-dicarboxylate (5.0779 g). The product was recrystallized from n-hexane to give pale yellowish prisms, m.p. 105° to 107° C.