[NH2:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][N:3]=1.[CH2:8]=O.[C:10]([C:12]1[CH:22]=[CH:21][C:15]2[N:16]=[C:17]([S:19][CH3:20])[S:18][C:14]=2[CH:13]=1)#[CH:11]>C1(C)C=CC=CC=1.Cl[Cu].C(S([O-])(=O)=O)(F)(F)F.C(S([O-])(=O)=O)(F)(F)F.[Cu+2]>[N:1]1[CH:8]=[C:11]([CH2:10][C:12]2[CH:22]=[CH:21][C:15]3[N:16]=[C:17]([S:19][CH3:20])[S:18][C:14]=3[CH:13]=2)[N:3]2[CH:4]=[CH:5][CH:6]=[CH:7][C:2]=12
A stirred mixture of 2-aminopyridine (100 mg, 1.1 mmol), paraformaldehyde (34 mg, 1.1 mmol), CuCl (5 mg, 0.06 mmol), and Cu(OTf)2 (19 mg, 0.06 mmol) in 3 mL of toluene in a pressure tube was flushed with argon. 6-Ethynyl-2-(methylthio)benzo[d]thiazole (327 mg, 1.6 mmol) from Step 3 of this Example was added. The reaction vessel was sealed and the mixture was heated in an oil bath at 120° C. for 6 h. LCMS analysis showed that the reaction was mostly complete. The reaction mixture was partitioned between EtOAc and saturated aq NaHCO3. The organic layer was washed with brine, dried over Na2SO4, and concentrated under reduced pressure. The residue was purified by silica gel chromatography eluting with 0-100% EtOAc in hexanes to afford 6-(imidazo[1,2-a]pyridin-3-ylmethyl)-2-(methylthio)benzo[d]thiazole (127 mg, 38%) as a brown oil. LCMS (ESI) m/z 312 (M+H)+.
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