N-Hydroxysuccinimide → 2,5-Dioxopyrrolidin-1-yl N-{[(9H-fluoren-9-yl)methoxy]carbonyl}-L-leucinate

HRID 429502Notes

Reaction equation

HRID 429502 reaction equation
[NH:1]([C:10]([O:12][CH2:13][CH:14]1[C:26]2[C:21](=[CH:22][CH:23]=[CH:24][CH:25]=2)[C:20]2[C:15]1=[CH:16][CH:17]=[CH:18][CH:19]=2)=[O:11])[C@H:2]([C:7]([OH:9])=[O:8])[CH2:3][CH:4]([CH3:6])[CH3:5].O[N:28]1[C:32](=[O:33])[CH2:31][CH2:30][C:29]1=[O:34]>CN(C=O)C.C(Cl)Cl>[NH:1]([C:10]([O:12][CH2:13][CH:14]1[C:15]2[C:20](=[CH:19][CH:18]=[CH:17][CH:16]=2)[C:21]2[C:26]1=[CH:25][CH:24]=[CH:23][CH:22]=2)=[O:11])[C@H:2]([C:7]([O:9][N:28]1[C:32](=[O:33])[CH2:31][CH2:30][C:29]1=[O:34])=[O:8])[CH2:3][CH:4]([CH3:6])[CH3:5]

Participants

5

Reactant 2

HCID 80170N-HydroxysuccinimideHCID 1549133Fmoc-leucine

Product 1

HCID 513405972,5-Dioxopyrrolidin-1-yl N-{[(9H-fluoren-9-yl)methoxy]carbonyl}-L-leucinate

Reagents, catalysts & solvents 2

HCID 6228DimethylformamideSolventHCID 6344DichloromethaneSolvent

Conditions

Temperature
25 °C

Procedure

Fmoc-L-Leu-OH (10 g,28.32 mmol) was dissolved in a mixture of DMF (10 ml)-CH2Cl2 (70 ml) and cooled in an ice-bath. N-Hydroxysuccinimide (3.58 g, 31.14 mmol, 1.1 equiv.) and dicyclohexylcarbodiimiide (6.06 g, 31.14 mmol, 1.1 equiv.) were added and the mixture was stirred at 0° C. for 1 hour and 25° C. for 14 hour. The reaction mixture was cooled in an ice-bath, filtered and the precipitate washed with CH2Cl2 (40 ml). The filtrate was evaporated to dryness and the residue dissolved in a mixture of dioxane (80 ml)-H2O (10 ml) to form a solution of Fmoc-Leu-OSu. A solution of anhydrous L-asparagine (5.606 g, 42.48 mmol, 1.5 equiv.) in 60 ml of Na2CO3 (2.50 g, 42.28 mmol, 1.5 equiv.) was added to the above solution of Fmoc-Leu-OSu. An additional 10 ml of dioxane was added and the reaction mixture was stirred at 25° C. for 2 hours. Ethyl acetate (200 ml) was added to the reaction mixture and the pH adjusted to about 2 by the addition of 5% aqueous HCl with stirring. The EtOAc layer was separated and the aqueous layer was extracted 4 more times with 100 ml each. The combined EtOAc extract was washed with saturated NaCl (100 ml), H2O (3×100 ml), dried over anhydrous Na2SO4, filtered and evporated to dryness. The residue was dissolved in DMF (60 ml) with warming (40-45° C.) and H2O added to the cloud point. The product crystallized after standing overnight. It was filtered, washed with ether and recrystallized from DMF-H2O. Lyophilization from dioxane gave 9.45 g (71.3%) of product. NMR and FAB mass spectroscopy confirmed the molecular formula C25H29N3O6 with an observed mass for (M+H)+, 468.3. The product Fmoc-Leu-Asn-OH was shown to be >95% pure by analytical HPLC. HPLC conditions were: column: Lichrosorb RP-8 (5μ); eluant: (A) 0.1M NaClO4 (pH 2.5)-(B) CH3CN; gradient: 40%-80% (B) in 20 minutes; flow 1 ml/l minute.; and detection: 210 nm.

Workup

  1. temperaturecooled in an ice-bath
  2. temperatureThe reaction mixture was cooled in an ice-bath
  3. filtrationfiltered
  4. washthe precipitate washed with CH2Cl2 (40 ml)
  5. customThe filtrate was evaporated to dryness
  6. dissolutionthe residue dissolved in a mixture of dioxane (80 ml)-H2O (10 ml)

Sources & evidence

ORD record
ord-ba24309f686d428fb80bc2072dec5adf
Source dataset
uspto-grants-2001_11
Patent number
US06316593B1

Reaction notes

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