2-Benzyl-4,5-dichloro-2,3-dihydropyridazin-3-one → 2-Benzyl-5-chloro-4-methoxypyridazin-3(2H)-one

HRID 2224277Notes

Reaction equation

HRID 2224277 reaction equation
[CH2:1]([N:8]1[C:13](=[O:14])[C:12](Cl)=[C:11]([Cl:16])[CH:10]=[N:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[CH3:17][O-:18].[Na+]>O1CCOCC1>[CH2:1]([N:8]1[C:13](=[O:14])[C:12]([O:18][CH3:17])=[C:11]([Cl:16])[CH:10]=[N:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

4

Reactant 2

HCID 7224382-Benzyl-4,5-dichloro-2,3-dihydropyridazin-3-oneHCID 10942334Sodium Methoxide

Product 1

HCID 135262132-Benzyl-5-chloro-4-methoxypyridazin-3(2H)-oneYield 90.2%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

To a stirring solution of 2-benzyl-4,5-dichloropyridazin-3(2H)-one (22.9 g, 89.8 mmol) in 1,4-dioxane (300 mL) at RT under argon was added NaOMe (22.4 mL, 25% solution in MeOH, 97.9 mmol) over 10 min by syringe. After 2 h, TLC indicated the reaction was completed. The reaction mixture was concentrated under reduced pressure. A saturated solution of NaCl (200 mL) was added and the resulting solution was extracted with CH2Cl2 (2×100 mL). The combined organic layers were dried (Na2SO4), concentrated under vacuum and purified by silica gel column chromatography eluting with CH2Cl2 to give the title compound, 2-benzyl-5-chloro-4-methoxypyridazin-3(2H)-one (20.3 g, 90%) as a colorless oil. TLC (CH2Cl2, Rf=0.4); MS [M+H]+ 251; HPLC retention time=2.74 min.

Workup

  1. concentrationThe reaction mixture was concentrated under reduced pressure
  2. additionA saturated solution of NaCl (200 mL) was added
  3. extractionthe resulting solution was extracted with CH2Cl2 (2×100 mL)
  4. dry with materialThe combined organic layers were dried (Na2SO4)
  5. concentrationconcentrated under vacuum
  6. custompurified by silica gel column chromatography
  7. washeluting with CH2Cl2

Sources & evidence

ORD record
ord-a70da90f2d4f409fad8a7c7f11105a53
Source dataset
uspto-grants-2008_05
Patent number
US07378418B2

Reaction notes

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