Ethanol → Demethoxyencecalin
Reaction equation
[C:1](=[O:4])([O-])[O-].[K+].[K+].C(O[CH:10](OCC)[CH:11]=[C:12]([CH3:14])[CH3:13])C.[CH2:18]([OH:20])[CH3:19].[C:21]1(C)[C:22](C)=[CH:23]C=[CH:25][CH:26]=1>>[C:18]([C:21]1[CH:26]=[CH:25][C:1]2[O:4][C:12]([CH3:13])([CH3:14])[CH:11]=[CH:10][C:23]=2[CH:22]=1)(=[O:20])[CH3:19]Participants
5
Conditions
- Temperature
- 140 °C
Procedure
83.8 g 4-hydroxy-acetophenone and 0.576 g anhydrous potassium carbonate were placed in 600 ml xylol in a argon atmosphere and heated to 140° C. 162.3 g 1,1-diethoxy-3-methyl-2-butene (77.9% in ethanol) was added in drops over 5 hours to this boiling solution with continuous distillation of the ethanol formed. After the solution had been stirred for 18 hours at 140° C., it was cooled to 20° C. and the organic phase was washed with 200 ml NaOH (5%) and concentrated in a vacuum. The raw product (orange-coloured oil) is distilled under a high vacuum (2.8 mbar/143° C.). The 6-acetyl-2,2-dimethyl-2H-1-benzopyran distillate obtained (90.2 g, 71.3% yield) had a content of 94.9%.
Workup
- customformed
- temperatureit was cooled to 20° C.
- washthe organic phase was washed with 200 ml NaOH (5%)
- concentrationconcentrated in a vacuum
- distillationThe raw product (orange-coloured oil) is distilled under a high vacuum (2.8 mbar/143° C.)
Sources & evidence
- ORD record
- ord-c94ea82674af4c22905b808ec4531a73
- Source dataset
- uspto-grants-1999_07
- Patent number
- US05919953
Reaction notes
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