Dimethylformamide → Dicyclohexylisourea
Reaction equation
[CH2:1]([NH:3][C:4](=O)[C@@H:5]1[CH2:9][CH2:8][CH2:7]N1)[CH3:2].[CH2:11](OC(N[C@H](C(O)=O)C)=O)[C:12]1C=CC=[CH:14][CH:13]=1.C[N:28](C)[CH:29]=[O:30].O1CCC[CH2:33]1>>[CH:4]1([N:3]([CH:1]2[CH2:2][CH2:14][CH2:13][CH2:12][CH2:11]2)[C:29]([NH2:28])=[O:30])[CH2:5][CH2:9][CH2:8][CH2:7][CH2:33]1Participants
Conditions
- Temperature
- 0 °C
Procedure
9.0 grams of N, N-dicyclohexylcarbodiimide was added to a solution of 5.6 grams of proline ethylamide and 9.0 grams of benzyloxycarbonyl alanine in a mixture of 5 ml. of dimethylformamide and 60 ml. of tetrahydrofuran cooled to -5 degrees C. After 1 hour of stirring at 0 degrees C., the reaction mixture was permitted to stand for 12 hours at room temperature, so resulting in the separation of N, N-dicyclohexylurea which was filtered off. The filtrate was evaporated; the evaporation residue dissolved in a mixture of ethyl acetate and water. The organic phase formed was gradually shook with 1M hydrochloric acid, water, 5% sodium hydrogen carbonate, with water, dried with anhydrous sodium sulphate and evaporated. The evaporation residue was crystallized from a mixture of 30 ml. of ether and 30 ml. of petroleum ether. 5.4 g of a product having a melting point of 99 to 101 degrees C. was obtained.
Workup
- waitto stand for 12 hours at room temperature
Sources & evidence
- ORD record
- ord-e8beaa664add4d48afc9ca7d6664cf9d
- Source dataset
- uspto-grants-1985_11
- Patent number
- US04554100
Reaction notes
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