These common heterocyclic compound, 2075-46-9, name is 4-Nitro-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. 2075-46-9
Example 1 3-Chloro-1H-pyrazol-4-amine hydrochloride (1a) A 1000-mL, multi-neck cylindrical jacketed reactor, fitted with a mechanical stirrer, temperature probe and nitrogen (N2) inlet, was charged with 4-nitropyrazole (50.0 g, 429 mmol) and palladium on alumina (5 wt %, 2.5 g). Ethanol (150 mL) was added, followed by a slow addition of concentrated hydrochloric acid (37 wt %, 180 mL). The reaction was cooled to 15 C., and triethylsilane (171 mL, 1072 mmol) was added slowly via addition funnel over 1 hour, while maintaining the internal temperature at 15 C. The reaction was stirred at 15 C. for 72 hours, after which the reaction mixture was filtered through a Celite pad and the pad was rinsed with warm ethanol (40 C., 2*100 mL). The combined filtrates were separated and the aqueous layer (bottom layer) was concentrated to ?100 mL. Acetonitrile (200 mL) was added and the resulting suspension was concentrated to ?100 mL. Acetonitrile (200 mL) was added and the resulting suspension was concentrated to ?100 mL. Acetonitrile (200 mL) was added and the resulting suspension was stirred at 20 C. for 1 hour and filtered. The filter cake was rinsed with acetonitrile (2*100 mL) and dried under vacuum at 20 C. to afford a white solid (?10:1 mixture of 1a and 1H-pyrazol-4-amine, 65.5 g, 99%): 1H NMR (400 MHz, DMSO-d6) delta 10.52 (bs, 3H), 8.03 (s, 1H); EIMS m/z 117 ([M]+).
Chemical properties determine the actual use. Each compound has specific chemical properties and uses. We look forward to more synthetic routes in the future to expand reaction routes of 2075-46-9.