反应详情

Add 2-methoxybenzoyl chloride (5.20 g, 35 mmol) to a solution of methyl 5-(N-hydroxycarbamimidoyl)pentanoate (5.3 g, 34 mmol) in pyridine (50 mL) under nitrogen at 0° C. and then heat the mixture at reflux for 6 h. Remove the solvent under reduced pressure, dilute the residue with ethyl acetate and wash with 1 N HCl. Wash the combined organic extracts with brine, dry over sodium sulfate and remove the solvent under reduced pressure. Purify the residue by flash column chromatography on silica gel, eluting with ethyl acetate/hexanes (1:4), to afford methyl 5-[5-(2-methoxyphenyl)[1,2,4]oxadiazol-3-yl]pentanoate (3.4 g, 33% over two steps): 1H NMR (CDCl3) δ1.7-1.85 (m, 2H), 1.85-2.00 (m, 2H), 2.35 (t, 2H), 2.95 (t, 2H), 3.65 (s, 3H), 3.95 (s, 3H), 7.00 (m, 2H), 7.45 (t, 1H), 8.00 (d, 1H).

1. temperatureheat the mixture
2. temperatureat reflux for 6 h
3. customRemove the solvent under reduced pressure
4. additiondilute the residue with ethyl acetate
5. washwash with 1 N HCl
6. washWash the combined organic extracts with brine
7. dry with materialdry over sodium sulfate
8. customremove the solvent under reduced pressure
9. customPurify the residue by flash column chromatography on silica gel
10. washeluting with ethyl acetate/hexanes (1:4)