[C:1]1([NH:7][C:8]([C:10]2[N:11]=[C:12]3[CH:17]=[CH:16][C:15]([C:18]#[N:19])=[CH:14][N:13]3[CH:20]=2)=[O:9])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.CN(C=O)C.[ClH:26].[CH2:27]([OH:29])[CH3:28]>>[ClH:26].[C:1]1([NH:7][C:8]([C:10]2[N:11]=[C:12]3[CH:17]=[CH:16][C:15]([C:18](=[NH:19])[O:29][CH2:27][CH3:28])=[CH:14][N:13]3[CH:20]=2)=[O:9])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1A suspension of 300 mg of N-phenyl-6-cyanoimidazo[1,2-a]pyridine-2-carboxamide (Intermediate 2) in 25 mL of ethanol containing 0.5 mL of DMF is cooled to 0° C. and then treated for 1 hour 40 minutes with hydrogen chloride gas. The reaction mixture is stirred at room temperature for 16 hours and then concentrated under reduced pressure to a small volume. The precipitate is filtered off by suction and washed with ethanol and ethyl ether to give 296 mg of ethyl 2-phenylcarbamoylimidazo[1,2-a]pyridine-6-carboximidate hydrochloride (1:1) in the form of a white solid, which is used without further purification for the rest of the synthesis.
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