Potassium Carbonate → 2-(4-methoxybenzyl)-4,5-dibromopyridazin-3(2H)-one

HRID 1966380Notes

Reaction equation

HRID 1966380 reaction equation
[Br:1][C:2]1[C:3](=[O:9])[NH:4][N:5]=[CH:6][C:7]=1[Br:8].C(=O)([O-])[O-].[K+].[K+].[CH3:16][O:17][C:18]1[CH:25]=[CH:24][C:21]([CH2:22]Cl)=[CH:20][CH:19]=1>[Br-].C([N+](CCCC)(CCCC)CCCC)CCC.CC#N>[CH3:16][O:17][C:18]1[CH:25]=[CH:24][C:21]([CH2:22][N:4]2[C:3](=[O:9])[C:2]([Br:1])=[C:7]([Br:8])[CH:6]=[N:5]2)=[CH:20][CH:19]=1

Participants

6

Reactant 3

HCID 11430Potassium CarbonateHCID 699934-Methyloxybenzyl chlorideHCID 2361814,5-Dibromo-2,3-dihydropyridazin-3-one

Product 1

HCID 469304402-(4-methoxybenzyl)-4,5-dibromopyridazin-3(2H)-one

Reagents, catalysts & solvents 2

HCID 74236Tetrabutylammonium BromideCatalystHCID 6342AcetonitrileSolvent

Conditions

Temperature
45 °C

Procedure

A mixture of 4,5-dibromopyridazinone (25 g, 98 mmol), anhydrous potassium carbonate (34 g, 246 mmol), 4-methoxybenzylchloride (14 mL, 103 mmol) and tetrabutylammonium bromide (1.6 g, 4.9 mmol) in CH3CN (200 mL) was stirred at 45° C. for 3 h and then at 80° C. for 2 h. The mixture was allowed to cool to 22° C. and filtered through a pad of Celite. The pad was washed with CH2Cl2, followed by EtOAc, and the combined filtrate was evaporated to dryness. The crude product was suspended in MeOH and sonicated. The solid was collected by suction filtration, washed with MeOH, and air-dried to give 2-(4-methoxybenzyl)-4,5-dibromopyridazin-3(2H)-one as a brown solid. The filtrate was concentrated and purified by silica gel chromatography, eluting with 20% hexane in CH2Cl2, to give 2-(4-methoxybenzyl)-4,5-dibromopyridazin-3(2H)-one as a pale yellow solid. 1H NMR (400 MHz, CDCl3) @ ppm 3.78 (s, 3H), 5.25 (s, 2H), 6.85 (d, J=8.53 Hz, 2H), 7.40 (d, J=9.03 Hz, 2H), 7.78 (s, 1H).

Workup

  1. waitat 80° C. for 2 h
  2. temperatureto cool to 22° C.
  3. filtrationfiltered through a pad of Celite
  4. washThe pad was washed with CH2Cl2
  5. customthe combined filtrate was evaporated to dryness
  6. customsonicated
  7. filtrationThe solid was collected by suction filtration
  8. washwashed with MeOH
  9. customair-dried

Sources & evidence

ORD record
ord-34c678c3405b4fbeb894ebbb952867ac
Source dataset
uspto-grants-2013_04
Patent number
US08420649B2

Reaction notes

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