反应详情

温度

-78 °C

To an ice-cold solution of 13.9 ml of diisopropylamine in 50 ml of anhydrous tetrahydrofuran there was added, by syringe, 38 ml of 2.6 N butyllithium in hexane. The mixture was cooled to -78° C. and a solution of 4.5 grams of 1,5,6,7-tetrahydro-3-methyl-4H-indazol-4-one was added dropwise. The mixture was stirred at -78° C. for 30 minutes and a solution of 10 ml of ethyl formate in 30 ml of anhydrous tetrahydrofuran was added dropwise. When the addition was complete, the reaction was allowed to warm to 0° C. and it was quenched by the dropwise addition of water (200 ml). After the mixture was stirred vigorously for a few minutes, the two layers which formed were separated. The aqueous layer was washed with ethyl ether and then acidified to a pH of about 4 with 5 N hydrochloric acid. The slurry which formed was extracted several times with dichloromethane and the combined extracts were dried and concentrated under reduced pressure to give 1,5,6,7-tetrahydro-5-hydroxymethylene-3-methyl-4H-indazol-4-one as a clammy yellow semi-solid.

1. additionWhen the addition
2. temperatureto warm to 0° C.
3. customit was quenched by the dropwise addition of water (200 ml)
4. stirringAfter the mixture was stirred vigorously for a few minutes
5. customthe two layers which formed
6. customwere separated
7. washThe aqueous layer was washed with ethyl ether
8. customThe slurry which formed
9. extractionwas extracted several times with dichloromethane
10. customthe combined extracts were dried
11. concentrationconcentrated under reduced pressure