5,5-Dibromobarbituric acid → 2-Bromo-1-(6-chloropyridin-3-YL)ethanone

HRID 863799Notes

Reaction equation

HRID 863799 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([C:8](=[O:10])[CH3:9])=[CH:4][N:3]=1.[Br:11]C1(Br)C(=O)NC(=O)NC1=O>C1COCC1.C(OCC)(=O)C>[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([C:8](=[O:10])[CH2:9][Br:11])=[CH:4][N:3]=1

Participants

5

Reactant 2

HCID 948775,5-Dibromobarbituric acid3×HCID 27796981-(6-Chloropyridin-3-yl)ethan-1-one

Product 1

HCID 194329212-Bromo-1-(6-chloropyridin-3-YL)ethanoneYield 73%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolvent2×HCID 8857Ethyl AcetateSolvent

Procedure

A solution of 784 mg of 2-chloro-5-acetylpyridine in 10 mL of THF was added via canula to a solution of 1.44 g of dibromobarbituric acid (DBBA) in 10 mL of THF. The resultant solution was heated at 50°-55° C. for 12 h, and then an additional 0.72 g DBBA was added. After stirring at 50°-55° C. for 2.5 more hours, 0.36 g DBBA was added. The mixture was allowed to stir for 2 h at which point NMR analysis of an aliquot indicated 87% conversion. The reaction mixture was cooled, diluted with ethyl acetate, washed with two portions of saturated aqueous sodium bicarbonate, water, and brine, dried over magnesium sulfate and concentrated. Purification by flash chromatography (silica gel, 15% ethyl acetate/hexane) provided 0.86 g (73%) of the title compound as a white solid: 1H NMR (400 MHz, CDCl3) δ8.96 (d, 1H, J=2.6 Hz), 8.21 (dd, 1H, J=2.5, 8.3 Hz), 7.46 (d, 1H, J=8.4 Hz), 4.37 (s, 2H). The NMR also indicated the presence of the corresponding 2-bromo derivative. The ~4:1 mixture was carried on through the synthesis.

Workup

  1. additionwas added
  2. temperatureThe reaction mixture was cooled
  3. washwashed with two portions of saturated aqueous sodium bicarbonate, water, and brine
  4. dry with materialdried over magnesium sulfate
  5. concentrationconcentrated
  6. customPurification by flash chromatography (silica gel, 15% ethyl acetate/hexane)

Sources & evidence

ORD record
ord-48c248b9c5b04f87ad2c220756274d12
Source dataset
uspto-grants-1996_10
Patent number
US05561142

Reaction notes

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