12-Tungstophosphoric acid (H3PW12O40) is found to be an efficient and recyclable catalyst in promoting a chemo- and regioselective condensation of hydrazines/hydrazides, diamines, and primary amines with various 1,3-dicarbonyl compounds in pure water at room temperature to afford pyrazoles, diazepines, and enaminones/enamino esters, respectively, in high yields.
Abstract An efficient and novel protocol for pyrazole synthesis has been developed by using fluoroboric acid as the acid catalyst. Simple and easily available 1,3-diketone and hydrazine derivatives are taken as the substrates for this purpose. The reaction entails mild reaction conditions and produces desired pyrazoles in good to excellent yields. Easy accessibility, easy handling, broad substrate
Room-Temperature Synthesis of Pyrazoles, Diazepines, <font>β</font>-Enaminones, and <font>β</font>-Enamino Esters Using Silica-Supported Sulfuric Acid as a Reusable Catalyst Under Solvent-Free Conditions
highly efficient regio- and chemoselective condensation of hydrazines/hydrazides, diamines, and primary amines with various β-dicarbonyl compounds at room temperature to afford pyrazoles, diazepines, and β-enaminones/β-enaminoesters under solvent-free conditions within 5–15 min.
Herein an efficient and simple protocol was developed for the synthesis of pyrazoles and phthalazin-1(2H)-ones from a common precursor hydrazines catalyzed by nickelchloride. The reactions proceeded in water at room temperature. The advantages of the protocol are that both the medicinally important scaffolds could be synthesized with low-cost catalyst, green solvent, relatively lower reaction time
Succinimide-N-sulfonic Acid Catalyzed One Pot, Efficient Synthesis of Substituted Pyrazoles
作者:Sagar R. Kande
DOI:10.13005/ojc/380431
日期:2022.8.31
A simple, facile and expeditious method to synthesis the pyrazoles carried out by using hydrazine/hydrazide and 1,3-dicarbonylcompounds in high yield. This eco-friendly protocol was catalyzed by succinimide-N-sulfonic acid and efficiently carried using water as a solvent within 15 minutes. The synthesized pyrazoles were characterized by H1, C13 NMR and IR spectrums.