反应详情

温度

-78 °C

4-Benzyloxy-3,5-dimethyl-benzoic acid (5.37 g, 20.9 mmol) is dissolved in CHCl3 (75 mL) and thionylchloride (10 mL) is added at rt. The mixture is stirred at reflux for 2 h. The mixture is evaporated to provide the crude acid chloride (5.62 g). A part of this material (2.75 g, 10 mmol) is dissolved in THF (10 mL) and cooled to −78° C. before it is treated with hydrazine (25 mL, 1 M solution in THF). The mixture is warmed to rt over a period of 15 h. The mixture is diluted with ether (150 mL) and washed with 1M aq. HCl (75 mL, then 5×50 mL). The combined aq. extracts are washed with ether (50 mL), basified with 33% aq. KOH and extracted with DCM (5×50 mL). The DCM extracts are dried over Na2SO4, filtered and evaporated to give 4-benzyloxy-3,5-dimethyl-benzoic acid hydrazide (1.29 g) as a white solid, LC-MS: tR=0.78 min, [M+1]+=271.19; 1H NMR (CDCl3): δ 2.30 (s, 6 H), 3.86 (s br, 2H), 4.82 (s, 2 H), 7.33-7.49 (m, 7 H), 7.56 (s br, 1 H).

1. temperatureat reflux for 2 h
2. customThe mixture is evaporated
3. customto provide the crude acid chloride (5.62 g)
4. temperatureThe mixture is warmed to rt over a period of 15 h
5. washwashed with 1M aq. HCl (75 mL
6. washThe combined aq. extracts are washed with ether (50 mL)
7. extractionextracted with DCM (5×50 mL)
8. dry with materialThe DCM extracts are dried over Na2SO4
9. filtrationfiltered
10. customevaporated