Lipoic acid → alpha Lipoic acid

HRID 1604445Notes

Reaction equation

HRID 1604445 reaction equation
[CH2:1]1[C@@H:5]([CH2:6][CH2:7][CH2:8][CH2:9][C:10]([OH:12])=[O:11])[S:4][S:3][CH2:2]1>C1CCCCC1.C(OCC)(=O)C>[CH2:1]1[CH:5]([CH2:6][CH2:7][CH2:8][CH2:9][C:10]([OH:12])=[O:11])[S:4][S:3][CH2:2]1

Participants

4

Reactant 1

HCID 6112Lipoic acid

Product 1

HCID 864alpha Lipoic acidYield 91.7%

Reagents, catalysts & solvents 2

HCID 8078CyclohexaneSolventHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
-7.5 °C

Procedure

A solution which contained 95.0 g R-(+)-thioctic acid and 5.0 g S-(-)-thioctic acid in a mixture of 225 ml cyclohexane and 25 ml ethyl acetate was cooled off from 35 to 40° C. down to -5 to -10° C., filtered and dried. 87.1 g thioctic acid were obtained in the novel modification as first crystallizate. The R-(+)-thioctic acid content was 93.5% with a melting range of 45 to 47° C.

Workup

  1. filtrationfiltered
  2. customdried

Sources & evidence

ORD record
ord-98b24aab45d445afa96f017bac499534
Source dataset
uspto-grants-1999_11
Patent number
US05994393

Reaction notes

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