Synthetic Route of 15953-45-4, These common heterocyclic compound, 15953-45-4, name is 5-Chloro-3-methyl-1H-pyrazole, 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.
(b) 5-Chloropyrazole-3-carboxylic acid..A mixture of 5-chloro-3-methylpyrazole (3.6 mmol; see step (a) above), water (6 mL) and terf-butanol (1.2 mL) was heated to 750C, after which KMnO4 (1.42 g, 9 mmol) was added. The mixture was stirred at 75C overnight and filtered hot. The solids were washed with boiling water. The combined cooled filtrates were extracted with EtOAc, and the combined extracts washed with NaCI (sat., aq.), dried (MgSO4) and concentrated. The crude solid was recrystallised from EtOAc/hexane/pentane to give the sub-title compound as white crystals (Yield: 350 mg (67%)). 1H-NMR (DMSO-d6, 400 MHz), delta 13.65 (br s, 1 H), 6.80 (s, 1 H). (d) 5-Chloropyrazole-3-carboxylic acid. A solution of KMnO4 (3.5 g, 22 mmol) in water (120 mL) was added in portions over a period of 5 h at 700C to a solution of 5-chloro-3-methylpyrazole (1.0 g, 8.8 mmol; see step (c) above) in water (50 mL) and terf-butanol (1 mL). The mixture was stirred at 7O0C overnight and filtered through Celite. The colourless filtrate was concentrated and acidified with HCI (aq., 2M). Filtration gave the title compound as a white powder which was used without further purification. (Yield: 913 mg, 80%). 1H-NMR (DMSO-d6): delta 6.80 (s, 1 H), 4.40 (br s, 1 H).
Statistics shows that 5-Chloro-3-methyl-1H-pyrazole is playing an increasingly important role. we look forward to future research findings about 15953-45-4.