Hydrochloric Acid → 4-[4-(3,4-dihydro-2H-quinoxalin-1-yl)phenyl]piperazine-1-carboxylic acid benzyl ester

HRID 41695Notes

Reaction equation

HRID 41695 reaction equation
C(OC([N:8]1[C:17]2[C:12](=[CH:13][CH:14]=[CH:15][CH:16]=2)[N:11]([C:18]2[CH:23]=[CH:22][C:21]([N:24]3[CH2:29][CH2:28][N:27]([C:30]([O:32][CH2:33][C:34]4[CH:39]=[CH:38][CH:37]=[CH:36][CH:35]=4)=[O:31])[CH2:26][CH2:25]3)=[CH:20][CH:19]=2)[CH2:10][CH2:9]1)=O)(C)(C)C.Cl.C(=O)([O-])[O-].[Na+].[Na+]>ClCCl.O1CCOCC1>[CH2:33]([O:32][C:30]([N:27]1[CH2:28][CH2:29][N:24]([C:21]2[CH:22]=[CH:23][C:18]([N:11]3[C:12]4[C:17](=[CH:16][CH:15]=[CH:14][CH:13]=4)[NH:8][CH2:9][CH2:10]3)=[CH:19][CH:20]=2)[CH2:25][CH2:26]1)=[O:31])[C:34]1[CH:39]=[CH:38][CH:37]=[CH:36][CH:35]=1

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 10340Sodium Carbonate2×HCID 668635804-[4-(4-(Benzyloxycarbonyl)piperazin-1-yl)phenyl]-3,4-dihydro-2H-quinoxaline-1-carboxylic acid tert-butyl ester

Product 1

HCID 668632134-[4-(3,4-dihydro-2H-quinoxalin-1-yl)phenyl]piperazine-1-carboxylic acid benzyl esterYield 99.8%

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolvent2×HCID 312751,4-DioxaneSolvent

Procedure

8.9 g of 4-[4-(4-(benzyloxycarbonyl)piperazin-1-yl)phenyl]-3,4-dihydro-2H-quinoxaline-1-carboxylic acid tert-butyl ester are placed in 220 ml of dichloromethane. 55 ml of a 4N solution of hydrochloric acid in dioxane are slowly added at 0° C. The mixture is stirred for 5 minutes under cold conditions and then it is allowed to return to ambient temperature. The reaction mixture is stirred at ambient temperature for 18 h and is then diluted with dichloromethane. A saturated aqueous sodium carbonate solution is added and then the addition is continued with solid sodium carbonate until a pH=7-8 is reached. The aqueous phase is extracted with dichloromethane. The organic phases are combined, washed with water, dried over sodium sulphate, filtered through a sintered glass filter and concentrated under vacuum. 7.2 g of 4-[4-(3,4-dihydro-2H-quinoxalin-1-yl)phenyl]piperazine-1-carboxylic acid benzyl ester are obtained in the form of an oil.

Workup

  1. customto return to ambient temperature
  2. stirringThe reaction mixture is stirred at ambient temperature for 18 h
  3. additionthe addition
  4. extractionThe aqueous phase is extracted with dichloromethane
  5. washwashed with water
  6. dry with materialdried over sodium sulphate
  7. filtrationfiltered through a sintered glass
  8. filtrationfilter
  9. concentrationconcentrated under vacuum

Sources & evidence

ORD record
ord-13601b1c60ea4c30bffc41631bb1ca9f
Source dataset
uspto-grants-2013_09
Patent number
US08530657B2

Reaction notes

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