Category: 28342-75-8

These common heterocyclic compound, 28342-75-8, name is 1,5-Dibromo-2,4-difluorobenzene, its 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. 28342-75-8

General procedure: E1 (3.00 equivalents), E2 (1 .00 equivalents) and E3 (1 .00 equivalents) were dissolved in dry DMF, NaH (6.00 equivalents) was added and the reaction mixture was stirred at 50 ¡ãC over night. Subsequently, NaH (3.00 equivalents) was added to the reaction mixture. The reaction mixture was poured on water and extracted repeatedly with dichloromethane. The combined organic layer was dried over sodium sulfate (Na2S04). The solvents were evaporated under reduced pressure to obtain Z1. Z1 (1 .00 equivalents) was dissolved in tert-butylbenzene and the solution was cooled to -30 ¡ãC. tert-Butyllithium (‘BuLi) (4.00 equivalents) was added dropwise and the reaction mixture was slowly heated up to 0 ¡ãC. After stirring for 30 minutes at 0 ¡ãC, the reaction mixture was cooled again to -30 ¡ãC. (0229) A solution of boron tribromide (BBr3, 2.2 equivalents) was added dropwise, the bath was removed and the reaction mixture was allowed to warm to room temperature (RT). Subsequently, the reaction mixture was heated at reflux at 120 ¡ãC for 5h. Volatiles were removed under reduced pressure to obtain Z3. (0230) A solution of Grignard compound/compounds [R1MgBr (1 .5 equivalents) / R2MgBr (1.5 equivalents)] was added dropwise to Z3 over a period of 30 min. After stirring for 1 h, MeOH was added to the reaction mixture and the solvents were evaporated under reduced pressure. The residue was dissolved in toluene and filtered with a pad of silica gel (toluene was used as eluent). The solvent was removed under reduced pressure. The crude product was dissolved in a minimum amount of toluene and then a small amount of heptane was added. The resulting precipitate was filtered to obtain P1 as a solid product.

Chemical properties determine the actual use. Each compound has specific chemical properties and uses. We look forward to more synthetic routes in the future to expand reaction routes of 28342-75-8.

Reference:
Patent; CYNORA GMBH; SEIFERMANN, Stefan; (41 pag.)WO2019/52940; (2019); A1;,
Bromide – Wikipedia,
bromide – Wiktionary

28342-75-8, Adding a certain compound to certain chemical reactions, such as: 28342-75-8, name is 1,5-Dibromo-2,4-difluorobenzene, belongs to bromides-buliding-blocks compound, can increase the reaction rate and produce products with better performance than those obtained under traditional synthetic methods. Here is a downstream synthesis route of the compound 28342-75-8.

To a solution of 1,5-dibromo-2, 4-difluorobenzene (Nucleosides, Nucleotides nucleic Acid, 201 (1 and2), 11-40 (2001) ) (8.8 g, 32.4 mmol) in diethylether (60 ml), 1.6 M n-BuLi in hexane (24.3 ml, 1.2 eq) was added at-78 C under N2 atmosphere. After stirring the reaction mixture at-78 C for 30 min, N-methyl-N- (methyloxy) acetamide (5.0 g, 1.5 eq) was dropped into to quench the reaction. The reaction mixture was stirred at the same temperature for further 30 min. After added acetic acid ( (5.2 ml), water (78 ml), the reaction mixture was extracted with diethylether. The obtained organic phase was washed by 0.2 N HCI aqueous, water, saturated NaHC03 aqueous and saturated NaCI aqueous, and dried over MgS04. After removing the solvent under reduced pressure, the residue was purified by Silica gel chromatography (n-Hexane/EtOAc = 49/1). Desired compound was obtained as pale yellow oil (4.94 g, 65percent).

In the field of chemistry, the synthetic routes of compounds are constantly being developed and updated. I will also mention this compound in other articles, 1,5-Dibromo-2,4-difluorobenzene, other downstream synthetic routes, hurry up and to see.

Reference:
Patent; SMITHKLINE BEECHAM CORPORATION; WO2005/85227; (2005); A1;,
Bromide – Wikipedia,
bromide – Wiktionary