Sodium Chloride → (2S,3S)-2-Hydroxy-3-methylpentanoic acid

HRID 1274805Notes

Reaction equation

HRID 1274805 reaction equation
N[C@H:2]([C:7]([OH:9])=[O:8])[C@H:3]([CH2:5][CH3:6])[CH3:4].N([O-])=[O:11].[Na+].C([O-])(O)=O.[Na+].[Na+].[Cl-]>OS(O)(=O)=O.O>[OH:11][C@@H:2]([C@@H:3]([CH3:4])[CH2:5][CH3:6])[C:7]([OH:9])=[O:8]

Participants

7

Reactant 4

HCID 5234Sodium ChlorideHCID 6306L-IsoleucineHCID 516892Sodium BicarbonateHCID 23668193Sodium Nitrite

Product 1

HCID 854025(2S,3S)-2-Hydroxy-3-methylpentanoic acid

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 1118Sulfuric AcidSolvent

Procedure

The synthesis was carried out in three steps, according to the following scheme: ##STR7## 1.1. Synthesis of(+)-(2S, 3S)-2-hydroxy-3-methylpentanoic acid [2]To a solution of (+)-L-isoleucine [1] (11.73 g, 89.4 mmol, [α]D20 =+40° (5% in 6M HCl)) in 300 ml of 1N aq. H2SO4 at 2° was slowly added (ca. 12 h) a solution of NaNO2 (19.5 g, 0.28 mol) in 300 ml of demineralised water. After stirring overnight at room temperature, 7.7 g of powdered NaHCO3 were added to bring the pH above 2. The solution was saturated with NaCl and extracted 6 times with ethyl acetate, maintaining the pH between 2 and 3 (1N aq. H2SO4, pH meter). After drying (Na2SO4), the organic layer was concentrated and the crude product (10.73 g, 91%) was recrystallised from hexane/ethyl acetate 9/1at -30° to give pure (+)-(2S,3S)-2-hydroxy-3-methylpentanoic acid [2].

Workup

  1. extractionextracted 6 times with ethyl acetate
  2. temperaturemaintaining the pH between 2 and 3 (1N aq. H2SO4, pH meter)
  3. dry with materialAfter drying (Na2SO4)
  4. concentrationthe organic layer was concentrated
  5. customthe crude product (10.73 g, 91%) was recrystallised from hexane/ethyl acetate 9/1at -30°

Sources & evidence

ORD record
ord-e36f6c9dff0641c19dc65912388a46ee
Source dataset
uspto-grants-2000_12
Patent number
US06159929

Reaction notes

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