Adding a certain compound to certain chemical reactions, such as: 70951-85-8, name is 4-Bromo-1-(tert-butyl)-1H-pyrazole, belongs to pyrazoles-derivatives 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 70951-85-8, HPLC of Formula: C7H11BrN2
Stage d) Preparation of 1-(1,1-Dimethylethyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (Intermediate 11) To a 20 L four-neck bottle, 4-bromo-(tert-butyl)pyrazole (1.15 kg, 5.66 mol) and THF (9.2 L) were added, then the mixture was cooled to between -78 C. and -85 C. and treated with nBuLi (6.23 mol) dropwise at that temperature. After addition the solution was stirred at the same temperature for 1 h and isopropyl pinacol borate (1.47 kg, 7.92 mol) was added dropwise. The reaction was complete after stirring for ?3 h (starting material<1.0% a/a by GC) then water (2.3 L) was added to quench the reaction; and the pH adjusted to 8-9 by addition of 3.45 kg 1M HCl. The aqueous phase was extracted with TBME (3.45 L*2), and the combined organic phase washed with 5% NaCl (3.45 L*2) and water (3.45 L) in sequence. The organic phase was evaporated to give the crude product. After subsequent recrystallization from heptanes the pure product was obtained as a white solid (GC purity 99.7% a/a) in a 63.5% th overall yield. (Two 20 L reactions were run, then combined in the heptane recrystallization).
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Reference:
Patent; GLAXO GROUP LIMITED; Atkinson, Francis Louis; Barker, Michael David; Douault, Clement; Garton, Neil Stuart; Liddle, John; Patel, Vipulkumar Kantibhai; Preston, Alexander George Steven; Wilson, David Matthew; US2013/40984; (2013); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics