1,1-Dibromoethane → HCID 66789204, compound

HRID 1660797Notes

Reaction equation

HRID 1660797 reaction equation
[CH2:1]([O:3][C:4](=[O:20])[C:5]1[CH:10]=[CH:9][C:8]([NH:11][C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])=[C:7]([NH2:19])[CH:6]=1)[CH3:2].[H-].[Na+].Br[CH:24](Br)[CH3:25].C([O-])([O-])=O.[K+].[K+]>CN(C)C=O.O>[CH2:1]([O:3][C:4]([C:5]1[CH:6]=[C:7]2[C:8](=[CH:9][CH:10]=1)[N:11]([C:12]([O:14][C:15]([CH3:16])([CH3:18])[CH3:17])=[O:13])[CH2:25][CH2:24][NH:19]2)=[O:20])[CH3:2]

Participants

7

Reactant 4

HCID 112011,1-Dibromoethane2×HCID 11430Potassium CarbonateHCID 24758Sodium hydride2×HCID 66789429HCID 66789429, compound

Product 1

HCID 66789204HCID 66789204, compound

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 6228DimethylformamideSolvent

Procedure

3-Amino-4-tert-butoxycarbonylamino-benzoic acid ethyl ester (3.1 g, 11.1 mmol) was dissolved in dimethylformamide (50 mL) and treated with NaH (−55% dispersion in oil) (0.3 g, 12.2 mmol). The reaction mixture was stirred at room temperature for 1 hour, dibromoethane (8.3 g, 3.8 mL, 44.2 mmol) was then added, and the mixture stirred for further 1 hour at room temperature. K2CO3 (6.11 g, 44.2 mmol) was added and the reaction mixture was stirred at 70° C. for 17 hours. A further aliquot of NaH (˜55% dispersion in oil) (0.3 g, 12.2 mmol) was added and, 3 hours later, a further aliquot of dibromoethane (2.1 g, 11.1 mmol). Stirring was continued at 70° C. for 18 hours. Water was added and the mixture was extracted three times with dichloromethane. The combined organic phases were dried over sodium sulfate and evaporated. The residue was purified by flash chromatography, yielding 3,4-dihydro-2H-quinoxaline-1,6-dicarboxylic acid 1-tert-butyl ester 6-ethyl ester as a light yellow solid, 1.0 g (29%), MS (ISP): m/e=307.3 (M+H+.); δH (300 MHz; CDCl3) 7.58 (1H, d), 7.34 (1H, d), 7.25 (1H, s), 4.33 (2H, q), 4.09 (1H, bs), 3.79 (2H, m), 3.43 (2H, m), 1.53 (9H, s), 1.37 (3H, t).

Workup

  1. stirringthe mixture stirred for further 1 hour at room temperature
  2. stirringthe reaction mixture was stirred at 70° C. for 17 hours
  3. stirringStirring
  4. waitwas continued at 70° C. for 18 hours
  5. extractionthe mixture was extracted three times with dichloromethane
  6. dry with materialThe combined organic phases were dried over sodium sulfate
  7. customevaporated
  8. customThe residue was purified by flash chromatography

Sources & evidence

ORD record
ord-8026573d499b46e2925920731a831c45
Source dataset
uspto-grants-2011_10
Patent number
US08030308B2

Reaction notes

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