Electric Literature of 1904-24-1,Some common heterocyclic compound, 1904-24-1, name is 3-Amino-5-ethylpyrazole, molecular formula is C5H9N3, 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.
Method 79; 6-Ethyl-2-chloro-4- (5-ethyl-lH-pvrazol-3-ylamino) pyrimidine 2,4-Dichloro-6-ethyl-pyrimidine (J. Am. Chem. Soc. 1936, 58, 78) (1.33g 7.53mmol) was stirred in ethanol (50ml) and 5-ethyl-lH-3-amino-pyrazole (Method 6 of WO 03/048133) (0. 836g, 7.53mmol) was added followed by sodium carbonate (1.25g) and the mixture stirred at 40C for 4 days then at 55C overnight. The insoluble inorganics were removed by filtration and solvent removed from the filtrate by evaporation. Water (100ml) was added and the mixture extracted with EtOAc (3 x 50ml). The extracts were combined and washed with water (50ml), brine (50ml), dried (MgS04) and solvent removed by evaporation. The residue was purified by column chromatography on silica gel eluting with hexane/EtOAc (100: 0 increasing in polarity to 0: 100) to give the title compound (210mg, 11%) a white solid. NMR (DMSO-d6 at 100C) : 1.20 (m, 6H), 2.50-2. 70 (m, 4H), 6.05 (s, 1H), 7.05 (br s, 1H), 9.70 (br s, 1H), 11.85 (br s, 1H) ; m/z 252 [MH] +.
These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 3-Amino-5-ethylpyrazole, its application will become more common.
Reference:
Patent; ASTRAZENECA AB; ASTRAZENECA UK LIMITED; WO2005/40159; (2005); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics