Phosphorus tribromide → 1-(2-Bromo-4-pyridyl)-2,3-bis(methoxycarbonyl)-6,7-dimethoxynaphthalene

HRID 324037Notes

Reaction equation

Cl[C:2]1[CH:7]=[C:6]([C:8]2[C:17]3[C:12](=[CH:13][C:14]([O:20][CH3:21])=[C:15]([O:18][CH3:19])[CH:16]=3)[CH:11]=[C:10]([C:22]([O:24][CH3:25])=[O:23])[C:9]=2[C:26]([O:28][CH3:29])=[O:27])[CH:5]=[CH:4][N:3]=1.P(Br)(Br)[Br:31]>ClC(Cl)C(Cl)Cl>[Br:31][C:2]1[CH:7]=[C:6]([C:8]2[C:17]3[C:12](=[CH:13][C:14]([O:20][CH3:21])=[C:15]([O:18][CH3:19])[CH:16]=3)[CH:11]=[C:10]([C:22]([O:24][CH3:25])=[O:23])[C:9]=2[C:26]([O:28][CH3:29])=[O:27])[CH:5]=[CH:4][N:3]=1

Participants

Conditions

Temperature: 100 °C

Procedure

A mixture of 1-(2-chloro-4-pyridyl)-2,3-bis(methoxycarbonyl)-6,7-dimethoxynaphthalene (22.7 g), phosphorus tribromide (52 ml) and 1,1,2,2-tetrachloroethane (100 ml) is stirred at 100° C. for 10 hours. After the reaction is complete, the mixture is concentrated under reduced pressure to remove the solvent, and thereto are added methylene chloride and an aqueous potassium carbonate solution. The methylene chloride layer is separated, and concentrated under reduced pressure to remove the solvent. The residue is crystallized from methanol to give 1-(2-bromo-4-pyridyl)-2,3-bis(methoxycarbonyl)-6,7-dimethoxynaphthalene (17.1 g).

Workup

concentrationthe mixture is concentrated under reduced pressure
customto remove the solvent
additionare added methylene chloride
customThe methylene chloride layer is separated
concentrationconcentrated under reduced pressure
customto remove the solvent
customThe residue is crystallized from methanol

Sources & evidence

ORD record: ord-bb898cb610164bfa94f883316c7c5530
Source dataset: uspto-grants-2001_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06214996B1

Reaction notes

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