Hydrochloric Acid → (R)-Dihydrolipoic acid

HRID 1068534

Reaction equation

HRID 1068534 reaction equation
S1C=CCS1.[CH2:6]1[C@@H:10]([CH2:11][CH2:12][CH2:13][CH2:14][C:15]([OH:17])=[O:16])[S:9][S:8][CH2:7]1.[BH4-].[Na+].Cl>C(=O)(O)[O-].[Na+].C1(C)C=CC=CC=1.O>[CH2:12]([CH2:11][C@@H:10]([SH:9])[CH2:6][CH2:7][SH:8])[CH2:13][CH2:14][C:15]([OH:17])=[O:16]

Participants

8

Reactant 4

HCID 313Hydrochloric AcidHCID 6112Lipoic acid2×HCID 5253311,2-DithioleHCID 4311764Sodium borohydride

Product 1

HCID 9834298(R)-Dihydrolipoic acidYield 80%

Reagents, catalysts & solvents 3

HCID 962WaterSolventHCID 1140TolueneSolventHCID 516892Sodium BicarbonateSolvent

Conditions

Temperature
0 °C

Procedure

The synthesis of a bidentate dithiol ligand was accomplished via the reduction of the coenzyme lipoic acid. The general procedure was described in I. C. Gunsalus, L. S. Barton, W. Gruber, J. Am. Chem. Soc. 78:1763-1766 (1956). Sodium borohydride (1.2 g) was added in 30-50 mg portions to a stirring suspension of lipoic acid (6.0 g) in 117 mL of 0.25 M sodium bicarbonate in 0° C. water. The reaction was stirred for 45 minutes at 0° C., after which 100 mL toluene was added and the mixture was acidified to pH˜2 with hydrochloric acid. The toluene layer was collected and saved. The aqueous layer was washed three times with 15 mL toluene. The organic layers were combined, dried with anhydrous magnesium sulfate, filtered, and the solvent removed under vacuum, leaving behind the product dihydrolipoic acid as a yellow oil (yield 80%).

Workup

  1. customThe toluene layer was collected
  2. washThe aqueous layer was washed three times with 15 mL toluene
  3. dry with materialdried with anhydrous magnesium sulfate
  4. filtrationfiltered
  5. customthe solvent removed under vacuum

Sources & evidence

ORD record
ord-5e69ae8e86d84abfacdbcd6af546474b
Source dataset
uspto-grants-2001_06
Patent number
US06251303B1

Linked notes

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