Tin dichloride dihydrate → (3R)-3-(Prop-2-en-1-yl)-3,4-dihydroquinoxalin-2(1H)-one

HRID 1071977Notes

Reaction equation

HRID 1071977 reaction equation
[N+:1]([C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][C:5]=1[NH:10][C@H:11]([CH2:16][CH:17]=[CH2:18])[C:12](OC)=[O:13])([O-])=O.Cl[Sn]Cl.O>CO>[CH2:16]([C@H:11]1[NH:10][C:5]2[C:4](=[CH:9][CH:8]=[CH:7][CH:6]=2)[NH:1][C:12]1=[O:13])[CH:17]=[CH2:18]

Participants

4

Reactant 2

HCID 43835034Tin dichloride dihydrateHCID 71404656Methyl (2R)-2-(2-nitroanilino)pent-4-enoate

Product 1

HCID 45115716(3R)-3-(Prop-2-en-1-yl)-3,4-dihydroquinoxalin-2(1H)-oneYield 47%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

To a solution of 2-fluroronitrobenzene (3.70 g, 26.06 mmol) and (2R)-2-aminopent-4-enoic acid (3.00 g, 26.06 mmol) in MeOH (30 mL), was added NaHCO3 (4.82 g, 57.33 mmol), and the reaction mixture was refluxed overnight. After cooling, concentrating, and chasing with benzene (3×30 mL), the crude product was dried on high vacuum pump overnight to give (2R)-2-[(2-nitrophenyl)amino]-pent-4-enoic acid, which was then dissolved in MeOH, cooled to 0° C. and saturated with HCl(g). The reaction was capped and the reaction mixture was stirred at room temperature overnight, concentrated, and then subjected to silica gel chromatography eluting with 40%-60% CH2Cl2 in hexanes to give methyl (2R)-2-[(2-nitrophenyl)amino]pent-4-enoate (3.75 g, 57% overall yield for 2 steps). Methyl (2R)-2-[(2-nitrophenyl)amino]pent-4-enoate was dissolved in MeOH (70 mL) and SnCl2.H2O (16.84 g, 74.63 mmol) was added After refluxing overnight, the reaction mixture was cooled and concentrated under reduced pressure. The crude material was poured into EtOAc and saturated NaHCO3 and extracted with EtOAc (3×100 mL). The combined organics were then washed with NaHCO3 (1×50 mL) and brine (1×50 mL), dried over sodium sulfate and concentrated in vacuo. The crude product was purified by flash chromatography on silica gel, eluting with 25%-40% EtoAc in Hexanes to give 1.31 g (47%) of (3R)-3-allyl-3,4-dihydroquinoxalin-2(1H)-one. LCMS (ES) m/z 189.3 (M+H)+.

Workup

  1. temperatureAfter refluxing overnight
  2. temperaturethe reaction mixture was cooled
  3. concentrationconcentrated under reduced pressure
  4. additionThe crude material was poured into EtOAc and saturated NaHCO3
  5. extractionextracted with EtOAc (3×100 mL)
  6. washThe combined organics were then washed with NaHCO3 (1×50 mL) and brine (1×50 mL)
  7. dry with materialdried over sodium sulfate
  8. concentrationconcentrated in vacuo
  9. customThe crude product was purified by flash chromatography on silica gel
  10. washeluting with 25%-40% EtoAc in Hexanes

Sources & evidence

ORD record
ord-fc34984b49634a0ea149dc74ac5b328e
Source dataset
uspto-grants-2005_06
Patent number
US06908921B2

Reaction notes

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