反应详情

Ethyl 4-(4-chlorophenyl)-2,4-dioxobutanoate sodium salt (10.0 g, 36.1 mM), synthesized from 4-chloroacetophenone and diethyloxalate employing lithiumdiisopropylamide as base, and 4-methoxyphenylhydrazine hydrochloride (6.31 g, 36.1 mM) in cold absolute EtOH (360 ml) were stirred at 0° for 4hr., at rt for 18 hr and then at reflux for 5 hr. The resulting solution was evaporated in vacuo, H2O (100 ml) was added and the aqueous phase extracted with Et2O (3×100 ml). The combined ether layerwas washed (brine), dried (Na2SO4) and concentrated in vacuo to give a crude solid which by NMR was a 5:1 mixture of the title compound tothe corresponding 1,3-diphenyl pyrazole. Recrystallization from EtOAc:hexane (2×) afforded pure 1 (7.93 g, 61%) as a white solid, mp=107°-108° C., MS, (DCI) m/e 357 (M+1).

1. temperatureat reflux for 5 hr
2. customThe resulting solution was evaporated in vacuo, H2O (100 ml)
3. additionwas added
4. extractionthe aqueous phase extracted with Et2O (3×100 ml)
5. washThe combined ether layerwas washed (brine)
6. dry with materialdried (Na2SO4)
7. concentrationconcentrated in vacuo
8. customto give a crude solid which by NMR