Acetic Acid → Levodopa

HRID 2413523Notes

Reaction equation

HRID 2413523 reaction equation
[NH2:1][C@H:2]([C:11]([OH:13])=[O:12])[CH2:3][C:4]1[CH:9]=[CH:8][C:7]([OH:10])=[CH:6][CH:5]=1.C[O:15]S([O-])(=O)=O.CC1C=CC=C2C=1N=C1C(C=CC=C1)=[NH+]2.C(O)(=O)C.O.NN>O.[Ni]>[OH:15][C:8]1[CH:9]=[C:4]([CH:5]=[CH:6][C:7]=1[OH:10])[CH2:3][C@@H:2]([C:11]([OH:13])=[O:12])[NH2:1]

Participants

7

Reactant 4

HCID 176Acetic AcidHCID 6057L-TyrosineHCID 24654Hydrazine hydrate (1:1)HCID 178503009HCID 178503009, compound

Product 1

HCID 6047LevodopaYield 1,139.3%

Reagents, catalysts & solvents 2

HCID 935NickelCatalyst2×HCID 962WaterSolvent

Procedure

1.8 g of tyrosine, 0.15 g of 9-methylphenazinium methylsulphate are placed into a reactor, dissolved in 1,000 ml of water. The resulting solution is acidified with acetic acid to the reaction medium pH of 4.5 and added with 30 ml of hydrazine hydrate and 5 g of Raney nickel. After filtering-off nickel, the resulting reaction mixture is evaporated to dryness under the pressure of 20 mm Hg, the residue is dissolved in 20 ml of methanol and the mixture is chromatographically separated into alumina and the desired product by eluting with a mixture consisting of n-propanol and a 34% aqueous ammonia taken in the ratio of 70:3. 1.1 g of 3,4-dihydroxyphenylalanine is thus obtained; the yield is 61% as calculated for the starting compound, m.p. of the product is 271°-272° C. The composition, in percent, is as follows:

Workup

  1. customis evaporated to dryness under the pressure of 20 mm Hg
  2. dissolutionthe residue is dissolved in 20 ml of methanol
  3. customthe mixture is chromatographically separated into alumina
  4. washthe desired product by eluting with a mixture

Sources & evidence

ORD record
ord-c7859c3dcbc34668aa15d48bf3675a55
Source dataset
uspto-grants-1988_01
Patent number
US04718994

Reaction notes

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