Synthetic Route of 2051-99-2, In the next few decades, the world population will flourish. As the population grows rapidly and people all over the world use more and more resources, all industries must consider their environmental impact. 2051-99-2, name is 1-Bromo-4-isobutylbenzene belongs to bromides-buliding-blocks compound, it is a common compound, a new synthetic route is introduced below.
General procedure: To a 50-mL two-neck round-bottom flask equipped with a cannula were added magnesium turnings (608 mg, 25 mmol), and the flask was heated at 80 C in vacuo for 1 h. A solution of the 4-isobutylphenyl bromide (426 mg, 2.0 mmol) in THF (5 mL) was added dropwise over 3 min under argon. The mixture was heated at 50 C until the reaction was initiated. Additional 4-isobutylphenyl bromide (1.71 g, 8.0 mmol) in THF (11.6 mL) was then added slowly via cannula over 15 min. The reaction mixture was heated at reflux for 3 h, after which a solution of 4-isobutylphenyl magnesium bromide 5 was obtained. To a separate 50-mL Schlenk tube was added anhydrous CoBr2 (21.9mg, 0.10mmol), and the tube was heated at 50C in vacuo for 2h. After cooling to room temperature, the cyclopropane-based bisoxazoline ligand 2 (0.12mmol) in THF (3mL) was added under argon. The resulting mixture was stirred for 1h at the same temperature, with 2-bromopropanoate 6 (1mmol) being added via syringe. The mixture solution was cooled to -80C, and the prepared Grignard reagent 5 (2.8mL, 0.5M in THF, 1.4mmol) was then added over 1h via syringe. The reaction mixture was stirred for another 6h at -80C and then quenched with saturated NH4Cl solution (5mL). The aqueous phase was extracted with diethyl ether (4¡Á10mL). The combined organic phases were dried over anhydrous Na2SO4, and concentrated under reduced pressure. The residue was purified by silica gel chromatography (n-hexane/ethyl acetate 100:1). 4.4.11 (S)-p-Tolyl-2-(4-isobutylphenyl)propanoate 7k Colorless oil, 93% yield, 87:13 er. The enantiomeric ratio was determined by HPLC with a Daicel Chiralcel OJ-H column (15% 2-propanol in n-hexane, 1 mL/min, 220 nm, minor tr = 8.37 min (R), major tr = 13.71 min (S)). [alpha]D20 = +26.4 (c 1.9, CHCl3). 1H NMR (300 MHz, CDCl3) delta 7.31-7.25 (m, 2H), 7.15-7.10 (m, 4H), 6.88-6.85 (m, 2H), 3.92 (q, J = 7.2 Hz, 1H), 2.47 (d, J = 7.2 Hz, 2H), 2.31 (s, 3H), 1.91-1.82 (m, 1H), 1.59 (d, J = 7.2 Hz, 3H), 0.91 (d, J = 6.6 Hz, 6H). 13C NMR (75 MHz, CDCl3) delta 173.4, 148.7, 140.7, 137.4, 135.3, 129.8, 129.5, 127.2, 121.0, 45.3, 45.1, 30.2, 22.4, 20.8, 18.6. HRMS (APCI-TOF): calcd for C20H25O2 [M+H]+ 297.1849, found 297.1842.
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-Bromo-4-isobutylbenzene, other downstream synthetic routes, hurry up and to see.
Reference:
Article; Liu, Feipeng; Bian, Qinghua; Mao, Jianyou; Gao, Zidong; Liu, Dan; Liu, Shikuo; Wang, Xueyang; Wang, Yu; Wang, Min; Zhong, Jiangchun; Tetrahedron Asymmetry; vol. 27; 14-15; (2016); p. 663 – 669;,
Bromide – Wikipedia,
bromide – Wiktionary