CC(C[AlH]CC(C)C)C.C(Cl)Cl.C([O:15][C:16]([C:18]1[N:19]=[C:20]2[CH2:25][N:24]([CH2:26][C:27]3[CH:32]=[CH:31][CH:30]=[CH:29][CH:28]=3)[CH2:23][CH2:22][N:21]2[CH:33]=1)=O)C>C1(C)C=CC=CC=1>[CH2:26]([N:24]1[CH2:23][CH2:22][N:21]2[CH:33]=[C:18]([CH:16]=[O:15])[N:19]=[C:20]2[CH2:25]1)[C:27]1[CH:32]=[CH:31][CH:30]=[CH:29][CH:28]=11.01 M solution of DIBAL in toluene (1 mL+0.2 mL+0.3 mL) was added to the dry CH2Cl2 (5 mL) solution of 7-benzyl-5,6,7,8-tetrahydroimidazo[1,2-a]pyrazine-2-carboxylic acid ethyl ester (283 mg) under a nitrogen atmosphere at −78° C. and stirred for 1.5 h. The mixture was quenched with 1 M HCl (5 mL). The reaction mixture was filtered through a pad of Celite. The filtrate was washed with 50% K2CO3 aq. and the aqueous layer was extracted with CH2Cl2. The combined organic layer was dried (K2CO3) and filtered. The filtrate was concentrated under reduced pressure. The residue was applied to silica gel column chromatography, then the column was eluted with CHCl3-acetone (9/1˜4/1) and CHCl3-MeOH (19/1). The titled compound was obtained as colorless crystals (148 mg, 61%).
読み込み中…