Electric Literature of 96450-53-2,Some common heterocyclic compound, 96450-53-2, name is 1-(2-Chloroethyl)-1H-pyrazole, molecular formula is C5H7ClN2, 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.
To methyl 2,6-dioxo-l,2,3,6-tetrahydropyrimidine-4-carboxylate (900 mg, 5.29 mmol) was added DMF (17 mL). The mixture was cooled with an ice bath and lithium hydride (66.4 mg, 7.94 mmol) was then added in portions. The mixture was stirred for 20 minutes and ((chloromethoxy)methyl)benzene (0.899 mL, 5.82 mmol) in DMF (3 mL) was then added slowly via syringe. The mixture was stirred a 00C for 30 minutes. Lithium hydride (66.4 mg, 7.94 mmol) was then added in portions and stirred for 10 minutes. Sodium iodide (793 mg, 5.29 mmol) and l-(2-chloroethyl)-l/f-pyrazole (829 mg, 6.35 mmol) were added in portions and then stirred at 00C for 30 minutes. The ice bath was removed. The mixture was stirred at room temperature for 4 hours and then heated to 500C with stirring for 3 days. The reaction mixture was cooled to room temperature. Water (25 mL) and methanol (25 mL) were added and the solvents were evaporated under vacuum at 65C to give a residue, which was partitioned between IN NaOH (75 mL) and diethyl ether (50 mL). The organic layer was separated and the aqueous layer was washed with diethyl ether (2 x 50 mL). The aqueous layer was then acidified to pH=3 with IN HCl and then extracted with n-BuOH (5 x 100 mL). The organic layers from the n-BuOH extraction were combined and the solvent was evaporated under vacuum to give a residue which was purified by HPLC (40% ACN in water containing 0.05% TFA) to give the title compound. MS [M+H] found 371.
These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 1-(2-Chloroethyl)-1H-pyrazole, its application will become more common.
Reference:
Patent; TAKEDA PHARMACEUTICAL COMPANY LIMITED; FENG, Jun; KEUNG, Walter; LARDY, Matthew; WO2010/129848; (2010); A2;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics