Bromide ion → HCID 18976445, compound

A solution of 2-(2-bromoethyl)-1,3-dioxane (3.41 ml, 4.88 g, 25.0 mmol) in dry THF (15 ml) was slowly added to dry magnesium turnings (0.67 g, 27.5 mmol) and ~10 mg iodine at room temperature under N2. After heat evolved and the iodine color vanished, the contents were heated to reflux and the remainder of the bromide solution was added dropwise over 10 min. After 2 h reflux, the alkylmagnesium-bromide solution was cooled to room temperature and transferred via syringe to a solution of 2-bromo-5-methoxybenzyl bromide (3.50 g, 12.5 mmol) in 20 ml dry THF. The contents were cooled to -10° with ice-salt, treated with Li2 CuCl4 in THF (0.45 ml of 0.1M solution), and allowed to stir at room temperature overnight for convenience. After 19 h, the solvent was evaporated and the residue partitioned between ether and 5% NH4Cl. The ether layer was washed with 5% NH4Cl, water, and brine, then dried over MgSO4, filtered, and evaporated to yield 4.59 g of a pale yellow oil. The crude material was purified by column chromatography (140 g silica gel, 50% ether/petroleum ether as eluent) under "flash" conditions to yield 2.31 gm (58%) of the dioxane as a colorless oil; tlc (silica gel, 50% ether/petroleum ether) Rf 0.48. A dimeric by-product, 1,2-bis(2-bromo-5-methoxyphenyl)ethane, was obtained as a white solid (1.02 g, 41%); mp 98°-101°. TLC (silica gel, 50% ether/petroleum ether) Rf 0.63.

1. temperatureAfter heat
2. temperaturethe contents were heated
3. temperatureto reflux
4. temperatureAfter 2 h reflux
5. waitAfter 19 h
6. customthe solvent was evaporated
7. customthe residue partitioned between ether and 5% NH4Cl
8. washThe ether layer was washed with 5% NH4Cl, water, and brine
9. dry with materialdried over MgSO4
10. filtrationfiltered
11. customevaporated

ORD record

ord-b1ede73a2a54494081c91cf0b3aa5fe0

Source dataset

uspto-grants-1998_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05807897