[H-].[Al+3].[Li+].[H-].[H-].[H-].[CH2:7]1[N:12]2[C:13]3[CH:19]=[CH:18][C:17]([C:20](OCC)=[O:21])=[CH:16][C:14]=3[N:15]=[C:11]2[CH2:10][CH2:9][CH2:8]1.C(=O)(O)[O-].[Na+].C(OCC)(=O)C>O1CCCC1>[CH2:7]1[N:12]2[C:13]3[CH:19]=[CH:18][C:17]([CH2:20][OH:21])=[CH:16][C:14]=3[N:15]=[C:11]2[CH2:10][CH2:9][CH2:8]1Lithium aluminum hydride (1.97 g, 51.9 mmol) was suspended in tetrahydrofuran (30 ml); and under an ice cooling, a solution (20 ml) of ethyl 1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyridine-7-carboxylate (6.34 g, 26.0 mmol) prepared in the Step 3-1-3 in tetrahydrofuran was slowly added thereto. After the mixture was stirred under an ice cooling for one hour, a saturated sodium bicarbonate solution (5 ml) was slowly added to the mixture at the same temperature while paying attention to the generation of heat. Further, ethyl acetate was slowly added to the mixture. The mixture was allowed to cool to a room temperature and filtered. The filtrate was thoroughly washed with chloroform. The filtrate was concentrated and purified by silica gel column chromatography (chloroform:methanol=20:1 to 10:1) to give the title compound (4.20 g, 80%) as a white powder.
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