Hydrochloric Acid → 8-Chloro-6-ethoxycarbonyl-5-methylthiochroman-4-ol
Reaction equation
[Cl:1][C:2]1[CH:3]=[C:4]([C:14]([O:16][CH2:17][CH3:18])=[O:15])[C:5]([CH3:13])=[C:6]2[C:11]=1[S:10][CH2:9][CH2:8][C:7]2=[O:12].[BH4-].[Na+].Cl>C(O)C.ClCCl>[Cl:1][C:2]1[CH:3]=[C:4]([C:14]([O:16][CH2:17][CH3:18])=[O:15])[C:5]([CH3:13])=[C:6]2[C:11]=1[S:10][CH2:9][CH2:8][CH:7]2[OH:12]Participants
Procedure
88.4 g (311 mmol) of the 8-chloro-6-ethoxycarbonyl-5-methylthiochroman-4-one obtained in the above step (5) was dissolved in 200 ml of ethanol, and further dissolved in 200 ml of dichloromethane. This solution was cooled to 5°~10° C., and 5.9 g (155 mmol) of sodium borohydride was added. The reaction mixture was stirred at the above temperature for 30 minutes, and further stirred at room temperature for 3 hours. Then, the reaction mixture was poured into 400 ml of a 5% hydrochloric acid aqueous solution and extracted with 900 ml of dichloromethane, and then the resultant organic layer was washed with a saturated sodium chloride aqueous solution and dried over anhydrous sodium sulfate. The solvent was distilled off to give 86.8 g (yield 97%) of 8-chloro-6-ethoxycarbonyl-5-methylthiochroman-4-ol.
Workup
- temperatureThis solution was cooled to 5°~10° C.
- stirringfurther stirred at room temperature for 3 hours
- extractionextracted with 900 ml of dichloromethane
- washthe resultant organic layer was washed with a saturated sodium chloride aqueous solution
- dry with materialdried over anhydrous sodium sulfate
- distillationThe solvent was distilled off
Sources & evidence
- ORD record
- ord-2d0c6b6b12b045d6bda5e58f3e858e4f
- Source dataset
- uspto-grants-1997_03
- Patent number
- US05607898
Reaction notes
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