Reference of 1621-91-6,Some common heterocyclic compound, 1621-91-6, name is 1H-Pyrazole-3-carboxylic acid, molecular formula is C4H4N2O2, 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.
Step 1 : To a mixture of 1 H-pyrazole-3-carboxylic acid (15.0 g, 134 mmol) and Cs2C03 (109 g, 335 mmol) in CH3CN (250 mL) was added CH3I (29.2 ml, 469 mmol) and the RM was stirred at rt for 14 h. The RM was filtered and filtrate was concentrated under reduced pressure, diluted with EtOAc and washed with water and brine before being dried. The solvent was evaporated under reduced pressure to give the crude product which was purified by CC (Si02; EtOAc/Hex) to yield the desired product (10.0 g, 53%). LC-MS (Method 3): m/z [M+H]+ = 141.3 (MW calc. 140.14); R, = 1.55 min.
The synthetic route of 1621-91-6 has been constantly updated, and we look forward to future research findings.
Reference:
Patent; GRUeNENTHAL GMBH; VOSS, Felix; RITTER, Stefanie; NORDHOFF, Sonja; WACHTEN, Sebastian; OBERBOeRSCH, Stefan; KLESS, Achim; WO2015/22073; (2015); A1;,
Pyrazole – Wikipedia,
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