Hydrochloric Acid → (+/-)-1,4-Bis(diphenylcarbamoyl)piperazine2-carboxylic acid

HRID 2226600Notes

Reaction equation

HRID 2226600 reaction equation
[C:1]1([N:7]([C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=2)[C:8](Cl)=[O:9])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.Cl.Cl.[NH:19]1[CH2:24][CH2:23][NH:22][CH2:21][CH:20]1[C:25]([OH:27])=[O:26].Cl>C(#N)C.[OH-].[Na+]>[C:1]1([N:7]([C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=2)[C:8]([N:19]2[CH2:24][CH2:23][N:22]([C:8](=[O:9])[N:7]([C:11]3[CH:12]=[CH:13][CH:14]=[CH:15][CH:16]=3)[C:1]3[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=3)[CH2:21][CH:20]2[C:25]([OH:27])=[O:26])=[O:9])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 65741N,N-Diphenylcarbamic chlorideHCID 2723757Piperazine-2-carboxylic acid dihydrochloride

Product 1

HCID 22004705(+/-)-1,4-Bis(diphenylcarbamoyl)piperazine2-carboxylic acidYield 26%

Reagents, catalysts & solvents 2

HCID 6342AcetonitrileSolventHCID 14798Sodium HydroxideSolvent

Procedure

A solution of 946 mg (4 mmole) of 98% diphenylcarbamoyl chloride in 4 ml of acetonitrile was added dropwise to a stirring solution of 406.2 mg (2 mmole) of piperazine-2-carboxylic acid dihydrochloride [E. Felder, S. Maffei, S. Pietra and D. Pitre, Helv. Chim., Acta, 43, 888 (1960)] in 4 ml of 2.5N sodium hydroxide at a temperature between 0° and 5° C. After the addition was completed, the stirring was continued for 4 hours and the solution was acidified with 2N hydrochloric acid while cooling in an ice bath. The reaction mixture was concentrated under reduced pressure and the residue was extracted with chloroform. After washing with water, the chloroform solution was dried over MgSO4 and concentrated in vacuo. The only product which solidified on cooling was triturated with isopropyl ether to give 270 mg (26%) of (±)-1,4-bis-(diphenylcarbamoyl)piperazine-2-carboxylic acid, m.p. 244°-246° C.

Workup

  1. additionAfter the addition
  2. temperaturewhile cooling in an ice bath
  3. concentrationThe reaction mixture was concentrated under reduced pressure
  4. extractionthe residue was extracted with chloroform
  5. washAfter washing with water
  6. dry with materialthe chloroform solution was dried over MgSO4
  7. concentrationconcentrated in vacuo
  8. temperatureon cooling
  9. customwas triturated with isopropyl ether

Sources & evidence

ORD record
ord-ce687019b440493f8ba05adbbb1e0e04
Source dataset
uspto-grants-1994_09
Patent number
US05348955

Reaction notes

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