Dimethyl Sulfoxide → N,N'-Dicyclohexylurea

HRID 373394Notes

Reaction equation

HRID 373394 reaction equation
FC(F)(F)C(O)=[O:4].N1C=CC=CC=1.[CH:14]1([N:20]=[C:21]=[N:22][CH:23]2[CH2:28][CH2:27][CH2:26][CH2:25][CH2:24]2)[CH2:19][CH2:18][CH2:17][CH2:16][CH2:15]1.CS(C)=O.C1(C)C=CC=CC=1>C(OCC)(=O)C>[C:21]([NH:20][CH:14]1[CH2:15][CH2:16][CH2:17][CH2:18][CH2:19]1)([NH:22][CH:23]1[CH2:28][CH2:27][CH2:26][CH2:25][CH2:24]1)=[O:4]

Participants

6

Reactant 4

HCID 679Dimethyl SulfoxideHCID 1140TolueneHCID 10868DicyclohexylcarbodiimideHCID 309472Pyridinium trifluoroacetate

Product 1

HCID 4277N,N'-Dicyclohexylurea

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent

Procedure

0.651 mmol of Boc-L-valyl-(2Rs, 3RS)-3-amino-2-hydroxypentanoyl-D-leucine t-butyl ester were admixed with 69.5 (0.360 mmol) of pyridine trifluoroacetate, 408.8 mg (1.982 mmol) of dicyclohexylcarbodiimide, 1.3 ml of DMSO and 2.5 ml of toluene. The reaction mixture was stirred at room temperature for 18 hours. After the completion of the reaction, the reaction mixture, having a yellow color, was diluted with 10 ml of ethyl acetate. Dicyclohexylurea thus formed was separated off by filtration. The organic layer was diluted with 10 ml of water, dried over anhydrous sodium sulfate, and distilled to remove the solvent therefrom, whereby an oily substance was obtained. The oily substance was admixed with 5 ml of ethyl acetate, whereby a further amount of dicyclohexylurea was crystallized and filtered off. The filtrate was distilled to remove the solvent therefrom, so that crude Boc-L-valyl-(RS)-3-amino-2-oxopentanoyl-D-leucyl t-butyl ester was obtained. The crude product was purified by a column chromatography (silica gel; and (1) dichloromethane:methanol (100:1), and (2) dichloromethane:ethyl acetate (12:1 to 10:1)) to obtain 178.2 mg of Boc-L-valyl-(RS)-3-amino-2-oxopentanoyl-D-leucyl t-butyl ester as white crystals. SI-MS: m/z 534 (M+1+).

Workup

  1. customAfter the completion of the reaction

Sources & evidence

ORD record
ord-8478153152c140e7971b8572b4892c54
Source dataset
uspto-grants-1992_11
Patent number
US05162500

Reaction notes

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