Reference of 881668-70-8,Some common heterocyclic compound, 881668-70-8, name is 5-Chloro-1H-pyrazole-3-carboxylic acid, molecular formula is C4H3ClN2O2, 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 E A mixture of TBTU (642 mg, 2.0 mmol), pyrazole-3-carboxylic acid or 5-chloro pyrazole-3-carboxylic acid (intermediate II) (1.0 mmol), the relevant arylamine (1.0 mmol), DIPEA (348 muL, 2.0 mmol) and DMAP (12 mg, 0.1 mmol) in dry DMF (5 mL) was stirred at 80 0C for 3 days. After cooling to rt the mixture was concentrated and hydrochloric acid (IM, 10 mL) was added. The mixture was extracted with EtOAc (4 x 10 mL) , the combined organic phases washed with NaCl (sat., aq.; 20 mL), dried (Na2SO4), concentrated and purified by chromatography (EtO Ac/heptane) to give the desired compound.
These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 5-Chloro-1H-pyrazole-3-carboxylic acid, its application will become more common.
Reference:
Patent; BIOLIPOX AB; WO2007/51981; (2007); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics