Microwave-assisted Heterocyclic Chemistry

Microwave‐Promoted, One‐Pot, Solvent‐Free Synthesis of 4‐Arylcoumarins from 2‐Hydroxybenzophenones

“…Hydrolysis of the ester group in the 3-position of the coumarin with aqueous NaOH gave 2-oxo-4-phenyl-2H-chromene-3-carboxylic acid (9) in quantitative yield. This acid was decarboxylated by using copper salts, as this method was described as being compatible with microwave irradiation to decarboxylate aromatic carboxylic acids [36] or indoles.…”

“…[6,7] The use of microwave irradiation in the synthesis of coumarins has been extensively studied. [8,9] Microwave-assisted organic synthesis (MAOS) has shown to be a valuable tool for reducing reaction times, getting cleaner reactions, improving yields, simplifying workup, and designing energysaving protocols. The increasing demand for clean and efficient "ecofriendly" chemical syntheses has focused general interest on solvent-free reactions, which when combined with microwave irradiation, have advantages from economical and environmental standpoints.…”

A three‐component process for the synthesis of 2,3‐dihydroquinazolin‐4(1H)‐one derivatives using nanosized nickel aluminate spinel crystals as highly efficient catalysts

“…During the last two decades, there has been interest in exploring the potential of microwave energy as a means of rate enhancement in the synthesis. Actually, microwave irradiation can be considered as a highly powerful tool owing to versatility, which enables the use of a wide variety of experimental conditions and very often leads to enhanced yields in significantly short reaction times . Several reasons have been proposed to account for the effect of microwaves on chemical reactions and catalytic systems such as rapid heating, superheating, selective heating, hot spots, and simultaneous cooling…”

Easy synthesis of new series of pteridine analogs: di- and tetra-hydropyrimido[4,5-d]pyrimidines via 5-pyrimidinecarbaldehydes

“…[15][16][17][18][19] It has become widely accepted that many classical reactions perform better under microwave irradiation than by conventional heating methods. [20][21][22][23][24] Microwave irradiation has been used to carry out a wide range of reactions in short times, with high yields and regioselectivity, and frequently without the need of solvents. 25 With the aim to tune up simple reaction methodologies, we have focused our strategy in the use of 4-aminopyrimidine-5-carbaldehydes as key precursors for the preparation of cited fused heterocyclic system (see Figure 2) because they have the appropriate spatial arrangement of atoms.…”