tert-Butyl acetate → N5-benzyloxycarbonyl-ornithine, t-butyl ester

HRID 21742

Reaction equation

HRID 21742 reaction equation
[CH2:1]([O:8][C:9]([NH:11][CH2:12][CH2:13][CH2:14][C@@H:15]([C:17]([OH:19])=[O:18])[NH2:16])=[O:10])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C(O[C:24]([CH3:27])([CH3:26])[CH3:25])(=O)C.Cl(O)(=O)(=O)=O>O>[C:24]([O:18][C:17](=[O:19])[C@H:15]([CH2:14][CH2:13][CH2:12][NH:11][C:9]([O:8][CH2:1][C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1)=[O:10])[NH2:16])([CH3:27])([CH3:26])[CH3:25]

Participants

5

Reactant 3

HCID 10908tert-Butyl acetateHCID 24247Perchloric AcidHCID 7009570H-Orn(Z)-OH

Product 1

HCID 7019766N5-benzyloxycarbonyl-ornithine, t-butyl esterYield 65%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

Nδ -(Benzyloxycarbonyl)-L-ornithine tert-butyl ester was prepared according to a general published procedure (Bodanszky, M.; Bodanszky, A.; The Practice of Peptide Synthesis; Spring Verlag: New York, 1984). Specifically, Nδ -(benzyloxycarbonyl)-L-ornithine (10.0 gm, 37.6 mmol, Sigma Chemicals, Inc.) was mixed with tert-butyl acetate (564 ml) and perchloric acid (5.91 ml, 69-72% aqueous solution) at room temperature. The reaction mixture became homogenous after 15 minutes and was stirred at room temperature for 2 days. Water (300 ml) was added to the reaction mixture, and the two layers obtained were separated. The organic layer was extracted twice (2×200 ml) with water, and the combined aqueous layers were adjusted to pH 9.5-10.0 with 50% NaOH. The aqueous layer was then filtered to remove a small amount of insoluble material, and the filtrate was extracted with ethyl acetate; (3×300 ml). The combined ethyl acetate extracts were dried over MgSO4 and were concentrated by rotary evaporation at reduced pressure to yield 7.5 g of Nδ -(benzyloxycarbonyl)-L-ornithine tert-butyl ester as an oil (65% yield). 1H NMR (DCCl3) δ1.44 (s,9H), 1.5-1.9 (m,4H), 3.23 (t,2H), 3.31 (t,1H), 5.09 (s,2H and s,1H broad), 7.35 (s,5H).

Workup

  1. customNδ -(Benzyloxycarbonyl)-L-ornithine tert-butyl ester was prepared
  2. customthe two layers obtained
  3. customwere separated
  4. extractionThe organic layer was extracted twice (2×200 ml) with water
  5. filtrationThe aqueous layer was then filtered
  6. customto remove a small amount of insoluble material
  7. extractionthe filtrate was extracted with ethyl acetate
  8. dry with materialThe combined ethyl acetate extracts were dried over MgSO4
  9. concentrationwere concentrated by rotary evaporation at reduced pressure

Sources & evidence

ORD record
ord-ff6c19b226ec42058a46ded2b9beb387
Source dataset
uspto-grants-1995_06
Patent number
US05424447

Linked notes

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