Microwaves in Heterocyclic Chemistry

Abstract

The palladium-catalyzed Heck [1], Suzuki [2] and Stille [3] reactions are robust and general methods for C±C bond-formation and have therefore emerged as important reactions in the synthesis of natural heterocyclic compounds.Hallberg and coworkers [4 a] have used a single-mode microwave oven [4 b] at 50 W to improve radical-mediated reduction and cyclization of the heterohalide 1 with HSn(CH 2 CH 2 C 10 F 21 ) 3 2 in benzotrifluoride (BTF). The authors claim the preparation of 3 in high yield (93 %) after 5 min, as illustrated in Scheme 8.1.The efficiency of fluorous Stille coupling reactions [5 a] is enhanced by use of microwave irradiation (Scheme 8.2). The reaction proceeds in 79 % yield after 2 min with DMF as the microwave-active solvent.

Microwave assisted synthesis of coumarin-purine derivatives: An approach to in vitro anti-oxidant, DNA cleavage, crystal structure, DFT studies and Hirshfeld surface analysis

“…Most typical challenges of today's world in constructing the potent organic bio-molecules are utilization of least energy, hazardous and expensive solvents minimization [1, 2, 3, 4]. Hence lots of organic reactions have been developed using microwave (MW) for chemical conversions to obtain compounds of chemical applications.…”

Design of New Benzo[h]chromene Derivatives: Antitumor Activities and Structure-Activity Relationships of the 2,3-Positions and Fused Rings at the 2,3-Positions

“…Benzochromene compounds have been synthesized using various strategies such as multicomponent reactions (MCRs) [ 14 , 15 , 16 , 17 ], heterogeneous catalytic methods [ 18 , 19 ], electrocatalytic processes [ 20 ], microwave [ 21 , 22 , 23 , 24 ] and ultrasound techniques [ 25 ]. Multicomponent reactions are some of the most successful procedures to prepare this class of molecules in good yields.…”

“…Multicomponent reactions are some of the most successful procedures to prepare this class of molecules in good yields. Meanwhile, microwave-assisted organic synthesis (MAOS) has been known for accelerating organic reactions, increasing product purities and simplifying the work-up [ 21 , 22 , 23 , 24 ]. Cyclocondensation reactions in “dry media” leading to heterocyclic systems have been performed under microwave irradiation [ 26 , 27 , 28 , 29 , 30 , 31 ], which were carried out in a neat, solvent-free state or in ethanol under microwave irradiation and helped to generate products not attainable through classical heating methods.…”

Synthesis and Molecular Descriptor Characterization of Novel 4-Hydroxy-chromene-2-one Derivatives as Antimicrobial Agents

“…Microwave irradiation has since been proven to be extremely useful for promoting and simplifying many condensation reactions which can be carried out both in solvents and under solvent-free conditions [ 13 , 14 , 15 , 16 , 17 ]. Microwave technology is particularly suitable for the rapid and automated production of libraries of compounds, as it enables organic chemists to reduce the time of synthesis from days and hours to minutes and even seconds [ 18 , 19 , 20 ]. In addition, suppressed formation of side-products and improved yields under microwave heating conditions has frequently been observed.…”