Electric Literature of 444-14-4,Some common heterocyclic compound, 444-14-4, name is 2-Bromo-4,6-difluoroaniline, molecular formula is C6H4BrF2N, traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.
Dissolve 2-bromo-4,6-difluoroaniline (40 g, 192 mmol) in methyldisulfide (250 mL) and heat to 75 C under nitrogen. Add isoamyl nitrite (67 mL, 500 mmol) dropwise via an addition funnel trough a reflux condenser (-1 drop/sec). Large exotherm may occur if addition is too fast. After addition is complete, heat the reaction to 95 C for 1 hour and cool to room temperature and concentrate in vacuo. Purify dark brown residue via silica gel chromatography eluting with hexanes to yield 30.3 g of 1-bromo-3, 5- difluoro-2-methylsulfanyl-benzene (66%). Charge a flask with isopropyl magnesium chloride (145 mL, 2M in THF, 290 mmol) and dilute with tetrahydrofuran (150 mL) and heat to 40 C under nitrogen. Add 1-bromo-3, 5-difluoro-2-methylsulfanyl-benzene (28 g, 117 mmol) slowly over 5 minutes. After 30 minutes, cool the reaction to 0 C and add trimethylborate (46 mL, 410 mmol) diluted with tetrahydrofuran (100 mL) via an addition funnel over 5 minutes. Partition the resulting gelatinous mixture between methylene chloride and 1N HC1. Acidify the aqueous layer to pH-1 (if needed) and vigorously stir the biphasic mixture until all solids are dissolved. the organic layer. Dry over sodium sulfate, filter and concentrate. Triturate with hexanes and filter to yield 14.7 g (61 %) of the title compound.
These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 2-Bromo-4,6-difluoroaniline, its application will become more common.
Reference:
Patent; ELI LILLY AND COMPANY; WO2005/73204; (2005); A1;,
Bromide – Wikipedia,
bromide – Wiktionary