1,2-Dibromo-4,5-dimethoxybenzene

Preparation A General procedure: To a solution of 4-bromoanisole (200.8 mg, 1.09 mmol, 1.0 equiv) in acetonitrile (2 mL) was added N-chlorosuccinimide(NCS) (158.3 mg, 1.19 mmol, 1.1 equiv) at rt to give a slightly cloudy mixture. Chlorotrimethylsilane (TMSCl) (14 μL, 0.11 mmol, 0.1 equiv) was then added drop-wise to the reaction mixture. Within a few minutes, the reaction mixture became clear pale yellow solution. The mixture continued to stir at rt for 1 h and was diluted with hexane. The biphasic mixture was concentrated on a rotary evaporator to a crude white solid-oil mixture. This mixture was taken up in hexane and filtered through a short plug of SiO2 and eluted with 5-10percent EtOAc-hexane solution. The clear filtrate was concentrated to obtain a mixture of 4-bromo-2-chloro-1-methoxybenzene (2a-Cl) and 2, 4-dichloro-1-methoxybenzene (2a-diCl) 237.0 mg (88percent of 2a-Cl and 11percent of 2a-diCl, based on NMR ratio 2a-Cl: 2a-diCl = 7.1: 1.0; as a pale yellow solid).General procedure: To a solution of alkoxybenzylalcohol 1 (0.2 mmol) in CF3CH2OH (1 mL) were added LiBr·H2O (0.6 mmol) and PhI(OAc)2 (0.6 mmol) atroom temperature. After completion of the reaction as indicated by TLC monitoring, saturated aq. Na2SO3 wasadded and the mixture was extracted with CH2Cl2. The combined organic layers were washed with brine, driedover anhydrous Na2SO4 and then concentrated in vacuo. The residue was purified by silica gel columnchromatography to afford pure dibrominated compounds 3.3, 4-Dimethoxybenzoic acid (25.0 g) was suspended in concentrated hydrochloric acid (35percent) (500 mL), and bromine (23.0 g, 1.05 equivalents) was added dropwise to the resultant suspension at 25° C. Subsequently, the resultant mixture was stirred for seven hours. Water (500 mL) was added to the mixture, and the mixture was stirred for one hour. Thereafter, the precipitated crystals were filtrated, and then dried under reduced pressure, to thereby produce crude crystals of 2-bromo-4, 5-dimethoxybenzoic acid (34.47 g) (yield: 96.2percent). [0029]

Molecular Weight:295.96
XLogP3:3.2
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:2
Exact Mass:295.88706
Monoisotopic Mass:293.88910
Topological Polar Surface Area:18.5
Heavy Atom Count:12
Complexity:127
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes