Imidazole as organocatalyst for multicomponent reactions: diversity oriented synthesis of functionalized hetero- and carbocycles using in situ-generated benzylidenemalononitrile derivatives
Heterogeneous ditopic ZnFe<sub>2</sub>O<sub>4</sub>catalyzed synthesis of 4H-pyrans: further conversion to 1,4-DHPs and report of functional group interconversion from amide to ester
Highly stable, environmentally benign ZnFe2O4 nanopowder was prepared, characterized and applied in the one-pot, three-component synthesis of 4H-pyrans in water. The ZnFe2O4 catalyst provides both acidic (Fe3+) and basic functionalities (O2−) as the reaction requires. The advantages of this method lie in its simplicity, cost effectiveness, environmental friendliness and easier scaling up for large scale synthesis. Water was exploited both as a reaction medium as well as a medium for synthesis of the catalyst. Moreover, water was the only byproduct. The present report puts forward an application of 4H-pyrans for the synthesis of 1,4-DHPs. This is the first attempt towards the synthesis of 4H-pyran-3-carboxylate from 4H-pyran-3-carboxamide. The corresponding functional group interconversion from amide to ester is rare in organic synthesis.
The preparation of pharmaceutically active 2-amino-4H-chromene derivatives has been achieved using a nano powder of natural clinoptilolite (CP) zeolite. A wide range of these worthy structures having diverse substituents on the 4H-chromene ring were efficiently synthesized via the reaction of an aromatic aldehyde and variety of enolizable C–H activated acidic compounds. Nano sized natural clinoptilolite
(2021). Facile Protocol for the Synthesis of 2-Amino-4H-Chromene Derivativesusing Choline Chloride/Urea. Organic Preparations and Procedures International: Vol. 53, No. 1, pp. 34-41.
The One-Step Synthesis of 3,4-Dihydropyrano[F]Chromene Derivatives in Under Grinding as an Environmentally Friendly Alternative
作者:Abolghasem Shameli Akandi、Ebrahim Balali、Talieh Mosavat、Mohammad Mehdi Ghanbari、Ali Eazabadi
DOI:10.13005/ojc/300225
日期:2014.7.1
1,4-diazabicyclo[2.2.2]octane (DABCO) was used as a catalyst for one-pot, three-component condensation reactions consisting of aromatic aldehydes, malononitrile and β-Naphtol under grinding at room temperature, to afford the corresponding dihydropyrano[c]chromenes in high yields. This method has the advantages of a simple operation, mild reaction conditions, high yields, by using a less toxic and low cost chemical as a catalyst.
DABCO‐Catalyzed Efficient Synthesis of Naphthopyran Derivatives via One‐Pot Three‐Component Condensation Reaction at Room Temperature
作者:Saeed Balalaie、Sorour Ramezanpour、Morteza Bararjanian、Jürgen H. Gross
DOI:10.1080/00397910701862865
日期:2008.3.1
(DABCO) has been used as a mild and efficient catalyst for synthesis of 2‐amino‐3‐cyano naphthopyran derivatives via a one‐potthree‐componentreaction of aromatic aldehydes, naphthols, and malononitrile at room temperature. The short reaction times, easy workup, good to excellent yields, and mild reaction conditions make this domino Knoevenagel–Michael reaction both practical and attractive.