Tributylphosphine → 2-Methoxy-6-(6-methoxy-4-((5-phenyl-1,2,4-thiadiazol-3-yl)methoxy)benzofuran-2-yl)imidazo[2,1-b][1,3,4]thiadiazole

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6-Methoxy-2-(2-methoxyimidazo[2,1-b][1,3,4]thiadiazol-6-yl)benzofuran-4-ol (Example 1H, 8.25 mg, 0.026 mmol) and (5-phenyl-1,2,4-thiadiazol-3-yl)methanol (Example 7B, 5 mg, 0.025 mmol) were put in a flask and this was flushed with N2. Dry THF (4 mL) was added and to this resulting suspension was added tri-n-butylphosphine (0.017 mL, 0.065 mmol) and a solution of 1,1′-(azodicarbonyl)dipiperidine (16.57 mg, 0.065 mmol) in dry THF (2.5 mL) was added dropwise via a syringe pump over 2 h. The resulting being suspension was stirred for an additional 2 hours at RT, at which time LC showed that no starting material remained. The mixture was diluted with EtOAc, washed with 0.2N HCl, sat aqueous NaHCO3 and brine, dried over anhydrous magnesium sulfate, filtered and concentrated. The residue was purified on silica gel chromatography (50% dichloromethane/hexanes to 100% dichloromethane to 1% EtOAc/CH2Cl2 to 7% EtOAc/CH2Cl2) and lyophilized in MeCN/water to give the title material (6.2 mgs, 49%). LC (Method B): 2.615 min. HRMS (ESI) calcd for C23H18N5O4S2 [M+H]+ m/z 492.0795, found 492.0828. 1H NMR (CDCl3, 400 MHz) δ ppm: 8.00 (dd, J=8.02, 1.37 Hz, 2H), 7.85 (s, 1H), 7.50-7.56 (m, 3H), 7.14 (s, 1H), 6.71-6.75 (m, 1H), 6.51 (d, J=1.57 Hz, 1H), 5.51 (s, 2H), 4.21 (s, 3H), 3.84 (s, 3H).

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