Hydrochloric Acid → (+/-)-Methyl 4-(2,5-dihydroxy-3,4,6-trimethylphenyl)-2-hydroxy-2-methylbutanoate
Reaction equation
[C:1]([C:3]([OH:24])([CH2:5][CH2:6][C:7]1[C:12]([CH3:13])=[C:11]([O:14]C(=O)C)[C:10]([CH3:18])=[C:9]([CH3:19])[C:8]=1[O:20]C(=O)C)[CH3:4])#N.[CH3:25][OH:26].Cl.[OH2:28]>>[OH:20][C:8]1[C:9]([CH3:19])=[C:10]([CH3:18])[C:11]([OH:14])=[C:12]([CH3:13])[C:7]=1[CH2:6][CH2:5][C:3]([OH:24])([CH3:4])[C:1]([O:26][CH3:25])=[O:28]Participants
Procedure
A solution of the crude (±)-2-cyano-4-(2,5-diacetoxy-3,4,6-trimethylphenyl)butan-2-ol prepared in Example 60 in 2000 ml. of anhydrous methanol was cooled in a dry ice-ethanol bath. When the internal temperature reached -50°, HCl gas was passed rapidly into the solution. Over the next 45 minutes, the external and internal temperatures were allowed to come to -20° and +5°, respectively. These temperatures were maintained until the solution was saturated with HCl The clear, dark brown solution was kept at +2° overnight, stripped of solvent at reduced pressure, diluted with 2000 ml. of H2O, heated at 40° under N2 for 2.0 hours, cooled and extracted with ethyl acetate and ether. The organic solutions were washed with saturated brine, dried over Na2SO4 and stripped of solvent to give (±)-methyl 4-(2,5-dihydroxy-3,4,6-trimethylphenyl)-2-hydroxy-2-methylbutanoate as a dark green-black oil. TLC indicated that under these conditions, virtually no (±)-methyl 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylate had been formed.
Workup
- customreached -50°
- customOver the next 45 minutes
- customto come to -20° and +5°
- temperatureThese temperatures were maintained until the solution
- additiondiluted with 2000 ml
- temperaturecooled
- extractionextracted with ethyl acetate and ether
- washThe organic solutions were washed with saturated brine
- dry with materialdried over Na2SO4
Sources & evidence
- ORD record
- ord-811863aa75514bad81fe51cabcb6030e
- Source dataset
- uspto-grants-1977_04
- Patent number
- US04018799
Reaction notes
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