Reference of 1752-88-1, These common heterocyclic compound, 1752-88-1, name is 3-Pyrazolidinone hydrochloride, its 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.
Alkylation of 20 with 21 to give 22 Potassium carbonate (8.28 g, 60.0 mmol), methyl 5-(3-bromopropyl)-thiophene-2-carboxylate (21, for preparation, see Billot, X. et al WO2004/037786, incorporated by reference herein, 5.66 g, 21.5 mmol), 3-pyrazolidinone HCl (20, 2.57 g, 21.0 mmol) and DMF (25 mL) were combined under argon and stirred at rt. After 3 d at rt, HPLC analysis indicated the reaction to be complete and EtOAc (100 mL) was added. The mixture was washed with water (2¡Á75 mL). The combined aqueous phase was back-extracted with EtOAc (50 mL). The combined organic phase was washed with brine (75 mL), filtered through filter paper and concentrated in vacuo to afford 7.5 g of a crude oil. Purification of the crude product by flash column chromatography on 75 g silica gel (50% CH2Cl2/hexane?CH2Cl2?20% EtOAc/CH2Cl2?100% EtOAc?10% MeOH/EtOAc, gradient) afforded 3.2 g (57%) of 22 which solidified on standing.
The synthetic route of 1752-88-1 has been constantly updated, and we look forward to future research findings.