反应详情

The compound obtained in (3) above (7.1 gm) was dissolved in 20 ml of methanol. To the solution was added 10 ml of 15% aqueous solution of sodium hydroxide and the mixture was stirred for 3 hours at room temperature. The reaction mixture was concentrated, acidified with concentrated hydrochloric acid, and extracted with chloroform. The chloroform layer was washed with water and saturated brine in this order and dried over anhydrous sodium sulfate. The solvent was evaporated, and the residue was slowly added to 50 ml of polyphosphoric acid heated to 110° C. and stirred for 4.5 hours. After the addition of 100 ml of ice-water, the reaction product was extracted with ethyl acetate, washed with water, saturated sodium bicarbonate and saturated brine in this order, and dried over anhydrous sodium sulfate. The solvent was evaporated, and the residue was subjected to silica gel column chromatography using a hexane-ethyl acetate (1:1) mixed solvent as an eluant to obtain fractions containing the target compound. The fractions were concentrated to produce 1.7 gm of the title compound.

1. concentrationThe reaction mixture was concentrated
2. extractionextracted with chloroform
3. washThe chloroform layer was washed with water and saturated brine in this order
4. dry with materialdried over anhydrous sodium sulfate
5. customThe solvent was evaporated
6. additionthe residue was slowly added to 50 ml of polyphosphoric acid
7. temperatureheated to 110° C.
8. stirringstirred for 4.5 hours
9. additionAfter the addition of 100 ml of ice-water
10. extractionthe reaction product was extracted with ethyl acetate
11. washwashed with water, saturated sodium bicarbonate and saturated brine in this order
12. dry with materialdried over anhydrous sodium sulfate
13. customThe solvent was evaporated
14. additionmixed solvent as an eluant
15. customto obtain fractions
16. additioncontaining the target compound
17. concentrationThe fractions were concentrated