反应详情

Compound 8 (300 mg, 1.27 mmol), 2-dimethyl propanoic anhydride (713.32 mg, 3.83 mmol), dimethyl aminopyridine (7 mg, 0.06 mmol), triethylamine (514.05 mg, 5.08 mmol) were weighed together in a 50 mL round bottom flask. This flask was placed in an oil bath at 60° C. with stirring for 2 days. Then, to the reaction mixture was added 1 g silica gel. The DMF was removed using oil pump and a silica gel plug was made. The plug was transferred on top of a column packed with silica gel, twenty times the weight of plug, eluted with chloroform, 1% methanol in chloroform and 5% methanol in chloroform. Fractions containing the product 9 (TLC) were pooled and evaporated to give solid compound. The overall yield was 40%. TLC Rf 0.45 (chloroform-methanol 10:1), m.p. 185.8-190.1° C., 1H NMR: δ 1.27 (s, 9H, pivaloyl); 7.19-7.40 (m, 3H, phenyl); 11.15 (s, 1H, 9-NH, exch); 11.94 (s, 1H, 9-NH, exch); 12.12 (s, 1H, 3-NH, exch).

1. customThis flask was placed in an oil bath at 60° C.
2. additionThen, to the reaction mixture was added 1 g silica gel
3. customThe DMF was removed
4. washeluted with chloroform, 1% methanol in chloroform and 5% methanol in chloroform
5. additionFractions containing the product 9 (TLC)
6. customevaporated
7. customto give solid compound