反应详情

Into 250 ml of anhydrous chloroform were added 5.0 g of 4-(3-methyl-5-oxo-2-pyrazolin-1-yl)benzoic acid and 25 ml of triethylamine and, further under ice-cooling, 12.5 ml of ethyl chlorocarbonate was added dropwise into the mixture. After evaporation of the solvent, the residue was dissolved in 200 ml of THF, the insolubles were filtered off, and then a solution of 2.08 g of NaBH4 dissolved in 60 ml of water was added dropwise into the filtrate, followed by stirring at room temperature for 2 hours. After evaporation of the solvent, water was added to the residue, and the mixture was adjusted with dil. hydrochloric acid to pH 4-5 and then extracted with chloroform. The organic layer was dried, concentrated and purified on silica gel column chromatograph with the use of chloroform-ethanl (100:1) as eluant, followed by recrystallization from chloroformethyl ether to give 1.16 g of 1-(4-hydroxymethylphenyl)-3-methyl-2-pyrazolin-5-one as colorless crystals.

1. temperaturefurther under ice-cooling
2. customAfter evaporation of the solvent
3. dissolutionthe residue was dissolved in 200 ml of THF
4. filtrationthe insolubles were filtered off
5. dissolutiona solution of 2.08 g of NaBH4 dissolved in 60 ml of water
6. additionwas added dropwise into the filtrate
7. customAfter evaporation of the solvent, water
8. additionwas added to the residue
9. extractionextracted with chloroform
10. customThe organic layer was dried
11. concentrationconcentrated
12. custompurified on silica gel column chromatograph with the use of chloroform-ethanl (100:1) as eluant
13. customfollowed by recrystallization from chloroformethyl ether