Application of 2075-45-8, A common heterocyclic compound, 2075-45-8, name is 4-Bromo-1H-pyrazole, molecular formula is C3H3BrN2, 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.
To a stirred solution of 4-bromo-pyrazole (10.44 g, 71.03 mmol) in anhydrous DMF (96 mL), cooled to 0 C., was slowly added NaH (60% in mineral oil) (3.13 g, 78.133 mmol). The solution was stirred for 1 hour at 0 C. 4-Methanesulfonyloxy-piperidine-1-carboxylic acid tert-butyl ester (19.82 g, 71.03 mmol) was added slowly and the reaction was heated to 100 C. overnight or until consumption of the pyrazole by NMR. The reaction was cooled to room temperature and water added (20 mL) followed by extraction with EtOAc. The combined extracts were washed with saturated aqueous NaCl (4*20 mL), dried with Na2SO4 and concentrated to afford 4-(4-bromo-pyrazol-1-yl)-piperidine-1-carboxylic acid tert-butyl ester as an orange oil. The oil was purified using silica gel chromatography eluding with 10% EtOAc/hexanes to 25% EtOAc/hexanes to provide 4-(4-bromo-pyrazol-1-yl)-piperidine-1-carboxylic acid tert-butyl ester as a white solid (10.55 g, 45% yield) with a Rf=0.4 (25% EtOAc/hexanes, using iodine as the stain). 1H NMR (CDCl3, 400 MHz) delta 7.46 (s, 1H), 7.43 (s, 1H), 4.23 (m, 3H), 2.88 (m, 2H), 2.10 (m, 2H), 1.88 (m, 2H), 1.47 (s, 9H).
The synthetic route of 2075-45-8 has been constantly updated, and we look forward to future research findings.
Reference:
Patent; AGOURON PHARMACEUTICALS, INC.; US2006/46991; (2006); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics