An efficient one-pot synthesis of functionalized 2-amino-4H-pyrans by a meglumine-catalyzed three-component reaction has been developed. A broad range of substrates including aromatic and heteroaromatic aldehydes, isatin derivatives, and acenaphthenequinone are condensed with enolizable C-H activated compounds and alkylmalonates to give the desired products in high to excellent yields. This methodology provides an alternative approach for rapid access to construct a diversity-oriented library of 4H-pyrans.
Diammonium Hydrogen Phosphate: An Efficient and Versatile Catalyst for the One‐Pot Synthesis of Tetrahydrobenzo[<i>b</i>]pyran Derivatives in Aqueous Media
Diammonium hydrogen phosphate was used as a mild, efficient, neutral, and cheap catalyst for the synthesis of various 4H-benzo[b]pyran derivatives via a one-pot, three-component condensation of aromatic aldehydes, active methylene compounds, and dimedone in aqueous media.
Synthesis and X-ray crystal structures of polyfunctionalized 4H-chromene derivatives via tricomponent reaction with Knoevenagel adducts as intermediates in aqueous medium
作者:Lucas Lima Zanin、David Esteban Quintero Jimenez、Matheus Pereira de Jesus、Luan Farinelli Diniz、Javier Ellena、André Luiz Meleiro Porto
DOI:10.1016/j.molstruc.2020.129226
日期:2021.1
triethylamine as catalyst. Twenty 4H-chromene derivatives were synthesized with 50–95% yields from aromatic aldehydes, 5,5-dimethyl-1,3-cyclohexadione and malononitrile or methyl cyanoacetate, being further characterized by Fourier Transform Infrared and NuclearMagneticResonance. We also report three crystal structures from the synthesized chromene derivatives, by single-crystal X-ray diffraction, showing