反应详情

A basic aqueous solution of sodium borohydride prepared beforehand by dissolving 23.8 g (0.630 moles) of NaBH4 at ambient temperature in 170 ml of H2O and 3.5 ml of 30% wt./vol. NaOH was added dropwise to a suspension of 3,4-dihydro-6-methyl-4-phenyl-2H-benzopyran-2-one of the formula (II) (100 g, 0.420 moles) in isopropanol (200 ml). Once addition was complete, the temperature was adjusted to 60° C. and the course of the reaction was monitored by TLC (eluent: cyclohexane/acetone: 70/30) until the substrate had completely disappeared. After 5 h, the reaction mixture was cooled to ambient temperature and HCl (2N) was added until a final pH of 7.0 was obtained. Stirring was continued for 30 min at ambient temperature, then the resultant suspension was filtered through a Buchner filter. The filtered solution was concentrated under reduced pressure and the crude residue was crystallised from toluene (280 ml) to yield 87.4 g (yield 86%) of 3-(2-hydroxy-5-methylphenyl)-3-phenylpropanol (VIII) as a white solid.

1. additionOnce addition
2. customwas adjusted to 60° C.
3. customwas obtained
4. waitwas continued for 30 min at ambient temperature
5. filtrationthe resultant suspension was filtered through a Buchner
6. filtrationfilter
7. concentrationThe filtered solution was concentrated under reduced pressure
8. customthe crude residue was crystallised from toluene (280 ml)