Reference of 77992-44-0 , The common heterocyclic compound, 77992-44-0, name is (5-Bromopyridin-2-yl)hydrazine, molecular formula is C5H6BrN3, 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.
A mixture of [5-BROMO-PYRIDIN-2-YL-HYDRAZINE] (4.34 g, 23.1 [MMOL)] and isobutyryl chloride (21.8 mL, 0.208 mol) is refluxed gently for 3 hours. The mixture is then cooled to room temperature. Hexane (22.0 mL) is added and the resulting slurry stirred at room temperature for 15 minutes and filtered. The filtrate cake is washed with hexane (3x) and dried in a vacuum-oven (30-35 [C)] for 48 hours. The product (5.90 g, yield 92.3%) may be obtained as an off-white powder. A biphasic mixture of the product (5.87 g, 21.2 [MMOL),] water (12.0 mL) and dichloromethane (18.0 mL) is cooled to 5 to [10 C.] A 1N aqueous solution of [NAOH] (21.5 mL) is added over a period of 10 minutes. The mixture is stirred in the bath for 15 minutes. The organic layer is isolated and the aqueous layer extracted with [DICHLOROMETHANE] (2x). The combined organic extracts are washed with 1: 1 brine-water and dried [(MGS04).] Most of the [DICHLOROMETHANE] is removed in vacuo. Ethyl acetate (8.0 mL) is added. After removing about half of the solvent, hexane (32.0 mL) is added. The slurry is stirred in an ice-water bath for 2 hours and filtered. The cake is washed with 9: 1 hexane-ethyl acetate (3x) and dried in a vacuum-oven (30-35 [C)] for 18 hours. The title compound may be obtained as a sandy tan powder (4. 72g, 92.5%).
The synthetic route of 77992-44-0 has been constantly updated, and we look forward to future research findings.
Reference:
Patent; PFIZER PRODUCTS INC.; WO2004/20440; (2004); A1;,
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