Reaction of Coumarin Derivatives with Nucleophiles in Aqueous Medium

Abstract

A series of heterocycles was synthesized by the reaction of α, β -unsaturated ketones of benzopyrans or coumarins with various nucleophiles in aqueous medium bearing two points of diversity. Compared to an identical library generated by conventional parallel synthesis, a microwaveassisted procedure dramatically decreased reaction times from hours to minutes, and yields of products and intermediates were improved remarkably. This synthetic approach is ecofriendly in nature which features water as solvent, microwave irradiation, and usage of a "green" catalyst (K 2 CO 3 ).

Trimethylpyrazole: a simple heterocycle reflecting Kitaigorodskii's packing principle

“…2, right). This kind of interaction is quite common for 4-unsubstituted pyrazoles and we only provide selected examples for comparison: ICEDUQ (Patra et al, 2004), LUNYID (Benisvy et al, 2009) and KITNOR (Kidwai et al, 2008)…”

Synthesis and antimicrobial activity of some new coumarin and dicoumarol derivatives

“…Reaction of coumarin 1 with aromatic aldehydes, namely, 3,4‐methylene dioxybenzaldehyde and/or 4‐methoxy benzaldehyde in equal molar ratio in the presence of piperidine as a base catalyst, afforded the condensation product 3‐arylidene‐6‐methyl‐4‐oxocomarin ( 7a,b ), but when the reaction is repeated in excess of 4‐hydroxy coumarin 1 , the dicoumarol derivatives 8a,b were obtained in high yield. Also, the dicoumarol 8a was prepared authentically by the addition of coumarin 1 to 3‐arylidine of 7a in the presence of base as piperidine.…”

Bio‐assisted synthesized Ag(0) nanoparticles immobilized on SBA‐15/cyclodextrin nanosponge adduct: Efficient heterogeneous catalyst for the ultrasonic‐assisted synthesis of benzopyranopyrimidines

“…Benzopyranopyrimidines are a class of heterocycles with potential pharmacological activity such as cytotoxic activity against cancer cell lines and in vivo anti‐tumour activity . To date, many efforts have been devoted to developing efficient protocols for the synthesis of these valuable scaffolds . Despite some successes, most disclosed methodologies suffer from some drawbacks such as application of toxic and environmentally unfriendly reaction media, high temperatures and long reaction times.…”