[CH2:1]([O:3][C:4](=[O:17])[CH2:5][C:6]1[N:10]2[CH:11]=[C:12]([C:15]#N)[CH:13]=[CH:14][C:9]2=[N:8][CH:7]=1)[CH3:2].O.[PH2]([O-])=[O:20].[Na+]>O.N1C=CC=CC=1.C(O)(=O)C.[Ni]>[CH2:1]([O:3][C:4](=[O:17])[CH2:5][C:6]1[N:10]2[CH:11]=[C:12]([CH:15]=[O:20])[CH:13]=[CH:14][C:9]2=[N:8][CH:7]=1)[CH3:2]
(6-Cyano-imidazo[1,2-a]pyridin-3-yl)-acetic acid ethyl ester (1.80 g, 7.46 mmol) is dissolved in a mixture of water (5.0 ml), pyridine (10 ml) and glacial acetic acid (5.0 ml). Sodium hypophosphite monohydrate (6.03 g, 56.4 mmol, 8 equiv) and Raney nickel (approx. 1.2 g) are added at room temperature. The reaction mixture is heated to 75° C. for 1 h, cooled to room temperature and filtered through Celite. The filtrate is extracted three times with EtOAc. The combined organic layers are washed with brine, dried over Na2SO4, filtered and concentrated in vacuo. Purification of the residue via flash chromatography (cylcohexane/EtOAc 1:1, +0.1% NEt3) affords the title compound (770 mg, 42%). 1H NMR (400 MHz, CDCl3): δ=10.01 (s, 1H), 8.69 (s, 1H), 7.73 (s, 1H), 7.72 (s, 1H), 7.69 (s, 1H), 4.23 (q, J=7.1 Hz, 2H), 4.04 (s, 2H), 1.30 (t, J=7.4 Hz, 3H). MS (ES+): 233 (M+H)+.
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