Trimethylamine oxide → 1-(6,7-Dichloro-2,3-dimethoxyquinoxalin-5-yl)-4-hydroxybutyl methyl sulphone

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Reaction Steps

A solution of 9-borabicyclo[3.3.1]nonane in tetrahydrofuran (0.5M, 1.07 ml, 0.537 mmol) was added to a stirred solution of 1-(6,7-dichloro-2,3-dimethyoxyquinoxalin-5-yl)-3-butenyl methyl sulphone (Example 93 (a)) (200 mg, 0.511 mmol) at room temperature under nitrogen. The mixture was stirred for 20 hours and then trimethylamine N-oxide (119 mg, 1.58 mmol) was added in portions. The mixture was stirred at room temperature for 2 hours and then at reflux for 30 minutes, cooled and concentrated under reduced pressure. The residue was purified by flash chromatography (eluting with 1:1 hexane:ethyl acetate then neat ethyl acetate) to give 1-(6,7-dichloro-2,3-dimethoxyquinoxalin-5-yl)-4-hydroxybutyl methyl sulphone (120 mg, 57%) as a mixture of diastereoisomers (by 1HNMR).

Provenance & Evidence