Phosphorus pentachloride → alpha-chloro-2-(2,4-dichlorobenzyloxy)benzaldehyde O-methyloxime

HRID 128903Notes

Reaction equation

[Cl:1][C:2]1[CH:20]=[C:19]([Cl:21])[CH:18]=[CH:17][C:3]=1[CH2:4][O:5][C:6]1[CH:16]=[CH:15][CH:14]=[CH:13][C:7]=1[C:8]([NH:10][O:11][CH3:12])=O.P(Cl)(Cl)(Cl)(Cl)[Cl:23].C(=O)(O)[O-].[Na+]>C(Cl)Cl>[CH3:12][O:11][N:10]=[C:8]([Cl:23])[C:7]1[CH:13]=[CH:14][CH:15]=[CH:16][C:6]=1[O:5][CH2:4][C:3]1[CH:17]=[CH:18][C:19]([Cl:21])=[CH:20][C:2]=1[Cl:1]

Participants

Conditions

Temperature: 0 °C

Procedure

2-(2,4-Dichlorobenzyloxy)-N-methoxybenzamide (10.44 g) was dissolved in dry methylene chloride (100 ml), phosphorus pentachloride (6.66 g) was added under ice-cooling over about 3 minutes to the solution, and the mixture was stirred at 0° C. for 1 hour. After completion of the reaction, a saturated aqueous solution of sodium bicarbonate (150 ml) was added slowly, and the mixture was extracted with methylene chloride (150 ml) twice, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The resulting crude product was purified by silica gel chromatography to give α-chloro-2-(2,4-dichlorobenzyloxy)benzaldehyde O-methyloxime (9.52 g) as crystals. A part of the crystals was recrystallized from ethyl acetate/n-hexane to give colorless crystals. mp 91°-92° C.

Workup

temperaturecooling over about 3 minutes to the solution
customAfter completion of the reaction
extractionthe mixture was extracted with methylene chloride (150 ml) twice
dry with materialdried over anhydrous magnesium sulfate
concentrationconcentrated under reduced pressure
customThe resulting crude product was purified by silica gel chromatography

Sources & evidence

ORD record: ord-86d81d53fe034b8f985070df8221e077
Source dataset: uspto-grants-1995_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05466661

Reaction notes

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