Acetonitrile → Ethyl (6-bromoimidazo[1,2-a]pyridin-3-yl)acetate

HRID 751264Notes

Reaction equation

HRID 751264 reaction equation
[CH2:1]([O:3][C:4](=[O:12])[CH:5]=[CH:6][CH:7](OC)OC)[CH3:2].C(#N)C.[NH2:16][C:17]1[CH:22]=[CH:21][C:20]([Br:23])=[CH:19][N:18]=1>C1(C)C=CC(S(O)(=O)=O)=CC=1.O>[CH2:1]([O:3][C:4](=[O:12])[CH2:5][C:6]1[N:18]2[CH:19]=[C:20]([Br:23])[CH:21]=[CH:22][C:17]2=[N:16][CH:7]=1)[CH3:2]

Participants

6

Reactant 3

HCID 6342AcetonitrileHCID 706222-Amino-5-bromopyridineHCID 68762381HCID 68762381, compound

Product 1

HCID 46839968Ethyl (6-bromoimidazo[1,2-a]pyridin-3-yl)acetateYield 107.1%

Reagents, catalysts & solvents 2

HCID 6101p-Toluenesulfonic acidCatalystHCID 962WaterSolvent

Procedure

Reflux a solution of 4,4-dimethoxy-but-2-enoic acid ethyl ester (3.3 g, 19.12 mmol) and toluene-4-sulfonic acid (0.02 g, 0.12 mmol) in a solution of 2:1 acetonitrile:water (90 mL) for 30 min. Add 2-amino-5-bromo-pyridine (1.65 g, 9.56 mmol) and reflux for 15 h. Cool and concentrate to ˜20 mL. Dilute the reaction with saturated aqueous sodium bicarbonate and extract into ethyl acetate. Combine and concentrate organic extracts. Flash chromatography using ethyl acetate/dichloromethane/methanol mixtures gives the subtitled compound as a brown oil (2.9 g). TOF MS ES+ exact mass calculated for C11H11BrN2O2 (p+1): m/z=283.0075 Found: 283.0082. 1H NMR (400 MHz, DMSO-d6) δ 8.68 (s, 1H), 7.55 (d, J=10 Hz, 1H), 7.49 (s, 1H), 7.34 (d, J=10 Hz, 1H), 4.15 (s, 2H), 4.09 (q, J=4 Hz, 2H), 1.18 (t, J=4 Hz, 3H). EA Calcd. For C11H11BrN2O2: C, 46.66; H, 3.92; N, 9.89; Found C, 46.56; H, 4.02; N, 9.60.

Workup

  1. temperatureCool
  2. concentrationconcentrate to ˜20 mL
  3. additionDilute
  4. customthe reaction with saturated aqueous sodium bicarbonate
  5. extractionextract into ethyl acetate
  6. concentrationCombine and concentrate organic extracts

Sources & evidence

ORD record
ord-5ca917728c5040768e631ac2e528564d
Source dataset
uspto-grants-2008_07
Patent number
US07405299B2

Reaction notes

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