Dicyclohexylcarbodiimide → BOC-Ser-Thr-OBzl

HRID 971577Notes

Reaction equation

HRID 971577 reaction equation
[NH2:1][C@H:2]([C:6]([O:8][CH2:9][C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1)=[O:7])[C@@H:3]([CH3:5])[OH:4].Cl.[NH:17]([C:24]([O:26][C:27]([CH3:30])([CH3:29])[CH3:28])=[O:25])[C@H:18]([C:21](O)=[O:22])[CH2:19][OH:20].CCCCC(F)(F)C(O)CC[C@@H]1[C@@H](CCCCCCC(O)=O)C(=O)C[C@H]1O.C1CCC(NC2CCCCC2)CC1.C1(N=C=NC2CCCCC2)CCCCC1>C(Cl)Cl>[NH:17]([C:24]([O:26][C:27]([CH3:30])([CH3:29])[CH3:28])=[O:25])[C@H:18]([C:19]([NH:1][C@H:2]([C:6]([O:8][CH2:9][C:10]1[CH:11]=[CH:12][CH:13]=[CH:14][CH:15]=1)=[O:7])[C@@H:3]([CH3:5])[OH:4])=[O:20])[CH2:21][OH:22]

Participants

6

Reactant 4

HCID 10868DicyclohexylcarbodiimideHCID 98766N-[tert-butoxycarbonyl]-L-serineHCID 16216248Benzyl L-threoninate--hydrogen chloride (1/1)HCID 7174909515-Hydroxy Lubiprostone Dicyclohexylammonium Salt

Product 1

HCID 131710001BOC-Ser-Thr-OBzl

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent3×

Conditions

Temperature
-5 °C

Procedure

47.0 g of H-Thr-OBzl.HCl in 300 ml of methylene chloride are added to a solution of 73.8 g of BOC-Ser-OH.Dicyclohexylammonium salt in 500 ml of methylene chloride and the mixture stirred for 10 minutes at room temperature and then cooled to -5° C. A solution of 40.1 g of dicyclohexylcarbodiimide in 90 ml of methylene chloride is added dropwise at this temperature. The mixture is stirred for 3 hours at -5° C. and overnight at room temperature. After filtering off the dicyclohexylurea and dicyclohexylamine hydrochloride the solution is extracted by shaking three times with 0.1 N hydrochloric acid, twice with 20% strength sodium chloride solution, once with 10% strength sodium bicarbonate solution and twice with 20% strength sodium chloride solution and is dried over sodium sulphate. The solution is concentrated to about 600 ml, cooled to 5° C. and further dicyclohexylurea is filtered off. After evaporation to dryness, the residue is crystallised from ethyl acetate-hexane in order to purify it.

Workup

  1. filtrationAfter filtering off the dicyclohexylurea and dicyclohexylamine hydrochloride the solution
  2. extractionis extracted
  3. stirringby shaking three times with 0.1 N hydrochloric acid
  4. dry with materialtwice with 20% strength sodium chloride solution, once with 10% strength sodium bicarbonate solution and twice with 20% strength sodium chloride solution and is dried over sodium sulphate
  5. concentrationThe solution is concentrated to about 600 ml
  6. temperaturecooled to 5° C.
  7. filtrationfurther dicyclohexylurea is filtered off
  8. customAfter evaporation to dryness
  9. customthe residue is crystallised from ethyl acetate-hexane in order
  10. customto purify it

Sources & evidence

ORD record
ord-a280e06b1af2405b8a557745bf512bac
Source dataset
uspto-grants-1979_07
Patent number
US04159981

Reaction notes

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