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.
Into a 250-mL 3-necked round-bottom flask purged and maintained with an inert atmosphere of 02, was placed ethyl lH-pyrazole-4-carboxylate (3 g, 21.41 mmol, 1.00 equiv), DCE (50 mL), cyclopropylboronic acid (3.51 g, 40.83 mmol, 1.90 equiv), Na2C03 (4.54 g, 40.8 mmol, 1.90 equiv), Cu(OAc)2 (3.88 g, 21.36 mmol, 1.00 equiv), bipyridine (3.34 g, 21.41 mmol, 1.00 equiv). The resulting solution was stirred for overnight at 70 C and then cooled to room temperature. The solids were filtered out. The filtrate was concentrated under vacuum. The residue was purified via reversed phase column with the following conditions: Column, CI 8 silica gel, 120 g, 20-45 muiotaeta, 100A; Mobile phase: water with 0.5% TFA and CH3CN (5% CH3CN up to 80% in 30 min). The collected fraction was concentrated under vacuum to afford ethyl l-cyclopropyl-lH-pyrazole-4-carboxylate (2.2 g, 57%) as a light yellow solid. MS (ESI, m/z): 181 [M+H]+.
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.