Citric Acid → (2S,3R)-2-(((Benzyloxy)carbonyl)amino)-3-(tert-butoxy)butanoic acid

HRID 1580869Notes

Reaction equation

HRID 1580869 reaction equation
CCCCC(F)(F)C(O)CC[C@@H]1[C@@H](CCC[CH2:18][CH2:19][CH2:20][C:21]([OH:23])=[O:22])C(=O)C[C@H]1O.C1CCC(N[CH:35]2[CH2:40][CH2:39][CH2:38][CH2:37][CH2:36]2)CC1.C(O)(=O)[CH2:42][C:43]([CH2:48]C(O)=O)([C:45](O)=O)[OH:44].[Cl-].[Na+].Cl.C1([N:63]=C=NC2CCCCC2)CCCCC1.[C:72]([O:75][CH2:76]C)(=[O:74])C>C(Cl)Cl.C(N(CC)CC)C>[NH:63]([C:72]([O:75][CH2:76][C:35]1[CH:36]=[CH:37][CH:38]=[CH:39][CH:40]=1)=[O:74])[C@H:20]([C:21]([OH:23])=[O:22])[C@@H:19]([CH3:18])[O:44][C:43]([CH3:42])([CH3:45])[CH3:48]

Participants

9

Reactant 6

HCID 311Citric AcidHCID 313Hydrochloric AcidHCID 5234Sodium ChlorideHCID 8857Ethyl AcetateHCID 10868DicyclohexylcarbodiimideHCID 7174909515-Hydroxy Lubiprostone Dicyclohexylammonium Salt

Product 1

HCID 7018812(2S,3R)-2-(((Benzyloxy)carbonyl)amino)-3-(tert-butoxy)butanoic acid

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolvent2×HCID 8471TriethylamineSolvent

Procedure

dicyclohexylammonium salt dissolved in ethyl acetate are 3 times shaken with dilute aqueous citric acid solution and three times with saturated aqueous sodium chloride solution, and the solution is dried over sodium sulphate and evaporated. The water-clear oil resulting therefrom is stirred with 3.34 g of H-Gln-Asp (OtBu)-Phe-OCH3. HCl in 40 ml of methylene chloride, 0.9 ml of triethylamine are added and a solution of 1.54 g of dicyclohexylcarbodiimide in 10 ml of methylene chloride is added dropwise. After rinsing this down with 10 ml of methylene chloride the suspension is stirred for 14 hours at room temperature. It is then placed for 2 hours in a refrigerator and the solid precipitate is filtered off, washed with a little methylene chloride, and the filtrate extracted by shaking with a large amount of ethyl acetate as described in 19. The amorphous evaporation residue is triturated with ether-hexane (1:1) and dried.

Workup

  1. dry with materialthe solution is dried over sodium sulphate
  2. customevaporated
  3. customThe water-clear oil resulting
  4. washAfter rinsing this down with 10 ml of methylene chloride the suspension
  5. waitIt is then placed for 2 hours in a refrigerator
  6. filtrationthe solid precipitate is filtered off
  7. washwashed with a little methylene chloride
  8. extractionthe filtrate extracted
  9. stirringby shaking with a large amount of ethyl acetate
  10. customThe amorphous evaporation residue is triturated with ether-hexane (1:1)
  11. customdried

Sources & evidence

ORD record
ord-d46973b7f464474ab1bcbe2b0d4f4680
Source dataset
uspto-grants-1976_01
Patent number
US03934008

Reaction notes

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