Potassium Hydroxide → Mandelic Acid

HRID 443612Notes

Reaction equation

HRID 443612 reaction equation
[C:1]([O:11]CC(N)CC)(=[O:10])[C@H:2]([C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1)[OH:3].C(OCC(N)CC)(=O)[C@@H](C1C=CC=CC=1)O.[OH-].[K+]>>[C:1]([OH:11])(=[O:10])[CH:2]([C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1)[OH:3]

Participants

4

Reactant 3

HCID 14797Potassium HydroxideHCID 70562055(-)-2-amino-1butanol D-(-)-mandelateHCID 131712145(-)-2-amino-1-butanol L-(+)-mandelate

Product 1

HCID 1292Mandelic Acid

Procedure

To a portion (1100 mls out of a total of 4800 mls) of the mother liquor plus methanol wash liquor obtained from resolution B, containing about 2.4 moles of a mixture of diastereomers, consisting of about 2.25 moles of (-)-2-amino-1-butanol L-(+)-mandelate and about 0.15 mole of (-)-2-amino-1-butanol D-(-)-mandelate, is added 180 grams of potassium hydroxide (88.8% real; 2.85 moles) to obtain a solution having an initial αD25° C of +24.7° ("as is", 10 cm cell). The solution is then heated at 115°-116° C. under pressure (40 psi) for 4 hours to obtain a mandelic acid solution having an αD25° C. of -3.0° ("as is", 10 cm cell). The resulting solution is essentially racemized, the negative rotation being due to the presence of the (-)-2-amino-1-butanol.

Workup

  1. washTo a portion (1100 mls out of a total of 4800 mls) of the mother liquor plus methanol wash liquor
  2. customobtained from resolution B
  3. customto obtain a solution
  4. customαD25° C of +24.7° ("as is", 10 cm cell)
  5. temperatureThe solution is then heated at 115°-116° C. under pressure (40 psi) for 4 hours

Sources & evidence

ORD record
ord-21b76a262ac3437ea32b580429b9db6b
Source dataset
uspto-grants-1981_04
Patent number
US04260815

Reaction notes

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