Benzyl Bromide → 2-Benzyl-4,5-dichloro-2,3-dihydropyridazin-3-one

HRID 2224234Notes

Reaction equation

HRID 2224234 reaction equation
[Cl:1][C:2]1[CH:7]=[N:6][NH:5][C:4](=[O:8])[C:3]=1[Cl:9].C([O-])([O-])=O.[K+].[K+].[CH2:16](Br)[C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1.N1NC(=O)C=CC=1>CN(C=O)C>[CH2:16]([N:5]1[C:4](=[O:8])[C:3]([Cl:9])=[C:2]([Cl:1])[CH:7]=[N:6]1)[C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1

Participants

6

Reactant 4

HCID 7498Benzyl BromideHCID 11430Potassium CarbonateHCID 681533(2H)-PyridazinoneHCID 732474,5-Dichloro-3-hydroxypyridazine

Product 1

HCID 7224382-Benzyl-4,5-dichloro-2,3-dihydropyridazin-3-oneYield 95%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

To a solution of dichloropyridazinone (50.0 g, 303.0 mmol) in DMF (200 mL) was added K2CO3 (50.3 g, 364.0 mmol) at RT under vigorous stirring. Benzylbromide (40.0 mL, 336.0 mmol) was added in rapid drops via a syringe. The resulting suspension was stirred at 50° C. for 1 h until all the pyridazinone was consumed as judged by HPLC. The reaction mixture was then poured into water (400 mL). The resultant suspension was stirred for 15 min at RT, and then filtered. The collected solid was rinsed thoroughly with water until no color was apparent in the filtrate. The solid was dried in a vacuum oven at 50° C. overnight to give the title compound, 2-benzyl-4,5-dichloropyridazin-3(2H)-one, (73.1 g, 95%) as pale yellow solid. HPLC: 3.17 min; MS, M+H=255.

Workup

  1. customwas consumed
  2. additionThe reaction mixture was then poured into water (400 mL)
  3. filtrationfiltered
  4. washThe collected solid was rinsed thoroughly with water until no color
  5. customThe solid was dried in a vacuum oven at 50° C. overnight

Sources & evidence

ORD record
ord-7f84a3495fd24f0e919381d05615e52a
Source dataset
uspto-grants-2008_05
Patent number
US07378418B2

Reaction notes

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