A visible light (white light-emitting
diode/direct sunlight)-driven
photochemical synthesis of a new series of biologically interesting
3-(alkyl/benzylthio)-4-hydroxy-2H-chromen-2-ones
has been achieved through a cross-dehydrogenative C3–H
sulfenylation of 4-hydroxycoumarins with thiols at ambient temperature
in the presence of rose bengal in acetonitrile under an oxygen atmosphere.
The notable features of this newly developed method are mild reaction
conditions, energy efficiency, metal-free synthesis, good to excellent
yields, use of low-cost materials, and eco-friendliness.
:
Ultrasonication, nowadays, is well-regarded as an effective green tool in implementing a plethora of organic transformations. The last decade has seen quite useful applications of ultrasound irradiation in synthetic organic chemistry. Ultrasound has already come out as a unique technique in green chemistry practice, for its inherent properties of minimizing wastes and reducing energy and time, thereby increasing the product yields with higher purities under milder reaction conditions. The present review summarizes ultrasound-promoted useful organic transformations involving both carbon-carbon and carbon-heteroatom (N, O, S) bond-forming reactions in the absence or presence of varying catalytic systems, reported during the period 2016-2020.
A water-mediated and catalyst-free practical method for the synthesis of a new series of pharmaceutically interesting functionalized 5-(2-arylimidazo[1,2-a]pyridin-3-yl)pyrimidine-2,4-(1H,3H)-diones has been accomplished based on a one-pot multicomponent reaction between arylglyoxal monohydrates, 2aminopyridines/2-aminopyrimidine, and barbituric/N,N-dimethylbarbituric acids under reflux conditions. The salient features of this protocol are avoidance of any additive/catalyst and toxic organic solvents, use of water as reaction medium, clean reaction profiles, operational simplicity, ease of product isolation/purification without the aid of tedious column chromatography, good to excellent yields, and high atom-economy and low E-factor.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.