Toluene → 1,2,3,4-Tetrahydropyrido[1,2-a]indol-10-carboxylic acid ethyl ester
反応式
[N:1]1[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=1[CH2:7][C:8]([O-:10])=[O:9].Cl[CH:12]1[CH2:17][CH2:16][CH2:15][CH2:14][C:13]1=O.[C:19]1(C)C=CC=C[CH:20]=1>C1C=CC=CC=1>[CH2:19]([O:9][C:8]([C:7]1[C:12]2[CH2:17][CH2:16][CH2:15][CH2:14][C:13]=2[N:1]2[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=12)=[O:10])[CH3:20]参加物
5
実験手順
2-Pyridylacetate (25 g, 150 mmol) and 2-chlorocyclohexanone were heated under reflux in dry benzene for 42 h. under a Dean Stark trap to remove water. Evaporation of the volatiles under reduced pressure gave a very thick red-brown oily residue. The residue was treated with toluene and filtered. The toluene filtrate was evaporated to give an orange-brown oil. The oil was purified on alumina eluting with 10% petroleum ether in toluene to give 2.7 g of 1,2,3,4-tetrahydropyrido[1,2-a]indol-10-carboxylic acid ethyl ester [modification of L. K. Dalton; T. Teitei Aust. J. Chem. 1969 22, 1525-1530]. The ethyl ester (1 g, 4 mmol) was dissolved in ethanol (40 mL) with warming. To the solution was added 2.5 N NaOH (30 mL). The reaction mixture was heated under reflux for 2 h, then allowed to cool and stir at room temperature for 2 days. The solution was acidified with 2N HCl and extracted into methylene chloride. Removal of the volatiles under reduced pressure gave a residue, which was purified by column chromatography on silica gel eluting with 5-15% ethyl acetate in hexane. The corresponding carboxylic acid was obtained. The carboxylic acid (210 mg, 0.98 mmol ) was dissolved in bromobenzene and heated at 170° C. for 15 min. The solvent was removed under reduced pressure to give a residue, which was purified on silica gel eluting with 100% hexane to remove bromobenzene followed by 5% ethyl acetate in hexane to isolate the product. Evaporation of the volatiles gave 1,2,3,4,-tetrahydropyrido[1,2-a]indole (140 mg), mp: 55-57° C. [M+H]+ 172 m/z. 1,2,3,4,-tetrahydropyrido[1,2-a]indole was formylated, converted to the nitroolefin and reduced to the corresponding ethylamine as described in Example 9 to give the title compound. The title compound was dissolved in ethanol and treated with an ethanolic solution of fumaric acid. After standing in a freezer overnight crystals formed. The solution was decanted from the crystals which were rinsed with ethyl ether and dried under reduced pressure to give the fumaric acid salt of the title compound, mp: 166-172° C. The filtrate was diluted with ethyl ether and a second crop of crystals was recovered, mp: 169-172° C.