Reference of 37622-90-5,Some common heterocyclic compound, 37622-90-5, name is Ethyl 4-pyrazolecarboxylate, molecular formula is C6H8N2O2, 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.
Compound 103: 1-Methyl-1H-pyrazole-4-carboxylic acid ethyl ester. Under anhydrous condition, to a solution of ethyl 4-pyrazolecarboxylate (3.00 g) in DMF (210 mL, c=0.1 molL-1) cooled by an ice bath, NaH (in mineral oil 60%, 1.10 g, 1.3 equiv.) was added in 3 portions (over 5 minutes). The mixture was stirred for 15 minutes, then methyl iodide (1.6 mL, 1.2 equiv.) was added. The ice bath was removed, and the reaction was stirred at room temperature for 2 Hrs. The mixture was hydrolysed with a saturated aqueous solution of NaHCO3 (1.0 L) and extracted twice with EtOAc (2*1.5 L). The organic layers were combined, washed with brine (0.5 L), dried over MgSO4 and concentrated. Purification by flash-chromatography (AcOEt in cyclohexane, 0 to 90%) afforded compound 103 as a colourless oil in 79% yield (2.60 g). 1H-NMR (400 MHz, DMSO): 1.26 (t, J 7.1 Hz, 3H, O-CH2-CH3); 3.87 (s, 3H, N-CH3); 4.21 (q, J 7.1 Hz, 2H, O-CH2-CH3); 7.82 (s, 1H, Ar); 8.29 (s, 1H, Ar). M/Z (M+H)+ = 155.1.
These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route Ethyl 4-pyrazolecarboxylate, its application will become more common.
Reference:
Patent; Domain Therapeutics; Mayer, Stanislas; Schann, Stephan; EP2666775; (2013); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics