反应详情

Using a Deanstark trap, a solution of compound 4 (50 mg, 0.14 mmol) in toluene was refluxed in the presence of p-toluenesulfonic acid (0.8 mg, 3 mol %) for 18 h. After solvent was removed in vacuo, the residue was purified by preparative HPLC (μBondasphere 5C18 100 A, 19×150 mm) and eluted using a linear gradient from 40 to 60% CH3CN in 0.1% TFA aq over 40 min at a flow rate of 5 mL/min, and the desired fraction was collected and lyophilized to obtain KPU-245; yield 11 mg (23%); m.p. 52-56° C., 1H HMR (300 MHz, DMSO-d6)δ 10.65 (s, 1H), 8.60 (s, 1H), 8.47 (s, 1H), 7.24-7.13 (m, 5H), 6.37 (s, 1H), 4.52 (br s, 1H), 3.20 (dd, J=3.7, 13.6 Hz, 1H), 2.95 (dd, J=5.0, 13.6 Hz, 1H), 1.31 (s, 9H), HRMS (EI): m/z 339.1584 (M+) (calcd for C19H21N3O3: 339.1583).

1. customAfter solvent was removed in vacuo
2. customthe residue was purified by preparative HPLC (μBondasphere 5C18 100 A, 19×150 mm) and
3. washeluted
4. customover 40 min
5. customthe desired fraction was collected
6. customto obtain KPU-245