Ethanol → Mandelic Acid

HRID 2293706Notes

Reaction equation

HRID 2293706 reaction equation
CO.C(O)C.[C:6]([OH:16])(=[O:15])[C@@H:7]([C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1)[OH:8]>C(O)(C)C>[C:6]([OH:16])(=[O:15])[CH:7]([C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1)[OH:8]

Participants

5

Reactant 3

HCID 702EthanolHCID 887MethanolHCID 11914(-)-Mandelic acid

Product 1

HCID 1292Mandelic Acid

Reagents, catalysts & solvents 1

HCID 3776IsopropanolSolvent3×

Procedure

The resolution of a racemic mixture of a compound of the formula I to prepare the (+) enantiomer of such compound is generally carried out using methanol, ethanol, or isopropanol, preferably isopropanol, as the organic reaction inert solvent. Preferably, the resolution is carried out by combining a racemic mixture of a compound of the formula I and (R)-(-)-mandelic acid in isopropanol, and stirring the mixture to form an optically enriched mandelic acid salt precipitate. The optically enriched precipitate is then recrystallized twice from isopropanol, after which the recrystallized precipitate is converted to the free base of the optically pure compound of formula I by partitioning it between dichloromethane and an aqueous base such as sodium hydroxide, sodium bicarbonate or potassium bicarbonate, preferably sodium hydroxide, or by stirring an alcoholic solution of the salt with a basic ion exchange resin. The free base, which is dissolved in the methylene chloride, can then be converted to the corresponding hydrochloric acid salt. Isolation of the mandelate may be conducted at temperatures from about 0° C. to about 40° C. About 25° C. is preferred.

Workup

  1. additionThe resolution of a racemic mixture of a compound of the formula I
  2. customto prepare the (+) enantiomer of such compound

Sources & evidence

ORD record
ord-9ae1ff4f31e6430fb70abeb3c12d9788
Source dataset
uspto-grants-1997_11
Patent number
US05686615

Reaction notes

Loading…