Electrogenerated acetonitrile anions/tetrabutylammonium cations: an effective catalytic system for the synthesis of novel chromeno[3′,4′:5,6]pyrano[2,3-d]pyrimidines

Synthesis of cobalt- ferrite and zinc oxide metal nanoparticles based-bentonite using SDS and their investigation as catalysts in synthesis of benzylbarbiturocoumarins

In this research, a suitable and efficient CoFe2O4@ZnO@Bentonite nano-catalyst was designed and synthesized by using zinc oxide (ZnO) and cobalt ferrite (CoFe2O4) nanoparticles and bentonite by microwave irradiation. Characteristics of the synthesized nanocomposite were investigated by Fourier transform infrared (FT-IR), scanning electron microscope (SEM), energy dispersive X-ray (EDX), transmission electron microscope (TEM), X-ray diffraction (XRD), Bruner- Emmett-Teller (BET) and vibrating sample magnetometer (VSM) techniques. The produced catalyst was effectively employed as a supported solid acid catalyst in mildly agitated three-component reactions involving aromatic aldehydes, 4-hydroxycoumarin, and 1,3-dimethyl-barbituric acid in a single pot to produce benzylbarbiturocoumarins. Starting materials were condensed via three C-C bond formation by CoFe2O4@ZnO@Bentonite as an efficient, recyclable, and environmentally safe nanocatalyst to obtain target products. The advantages of this method include using a natural substrate, small amounts of catalyst, aqueous media, performing reactions at ambient temperature, simple separation and purification of products, and good yields with short reaction times.

Practice of green chemistry strategies in synthetic organic chemistry: a glimpse of our sincere efforts in green chemistry research

This feature article summarises our recent contributions (2019-2023) in designing and developing a handful of promising organic transformations for accessing several diversely functionalised biologically relevant organic scaffolds, following the green chemistry principles, particularly focusing on the application of low-energy visible light, electrochemistry, ball-milling, ultrasound, and catalyst- and additive-free synthetic strategies.

An acid-based DES as a novel catalyst for the synthesis of pyranopyrimidines

Deep eutectic solvents have countless advantages over normal solvents, and in addition to complying with the principles of green chemistry, depending on their nature, they can also act as catalysts. The use of deep eutectic solvents as acid catalysts has several advantages such as non-toxicity, a catalytic effect similar to or higher than the acid itself, and the possibility of recovery and reuse without significant loss of activity. In this project, A novel deep eutectic solvent (MTPPBr-PCAT-DES) was prepared from a one-to-one mole ratio of methyltriphenyl-phosphonium bromide (MTPPBr) and 3,4-dihydroxybenzoic acid (PCAT = protocatechuic acid) and characterized by various techniques such as FT-IR, TGA/DTA, densitometer, eutectic point, 1H NMR, 13C NMR and 31P NMR. Then, it was used as a novel and capable catalyst for the synthesis of pyranopyrimidines from the multicomponent condensation reaction of barbituric acid, 4-hydroxycoumarin, and aromatic aldehydes in mild conditions, short reaction times, and high yields.

Importance of Hybrid Catalysts toward the Synthesis of 5H-Pyrano[2,3-d]pyrimidine-2-ones/2,4-diones (Thiones)

The pyranopyrimidine core is a key precursor for medicinal and pharmaceutical industries due to its broader synthetic applications as well as its bioavailability. Among its four possible isomers, we found that 5H-pyrano[2,3-d]pyrimidine scaffolds have a wide range of applicability, and in recent years, they have been intensively investigated, but the development of the main core is found to be more challenging due to its structural existence. In this review article, we cover all of the synthetic pathways that are employed for the development of substituted 4-aryl-octahydropyrano/hexahydrofuro[2,3-d]pyrimidin-2-one (thiones) and 5-aryl-substituted pyrano[2,3-d]pyrimidindione (2-thiones) derivatives through a one-pot multicomponent reaction using diversified hybrid catalysts such as organocatalysts, metal catalysts, ionic liquid catalysts, nanocatalysts, green solvents, catalyst-/solvent-free conditions, and miscellaneous catalysts as well as the mechanism and recyclability of the catalysts. This review mainly focuses on the application of hybrid catalysts (from 1992 to 2022) for the synthesis of 5H-pyrano[2,3-d]pyrimidine scaffolds. This review will definitely attract the world's leading researchers to utilize broader catalytic applications for the development of lead molecules.

Electrochemically Induced Michael Addition Reaction: An Overview

Due to its high potential for the formation of carbon-carbon bonds, Michael addition reaction is one of the closest reactions to the heart of synthetic organic chemists. Electrochemistry presents a very stimulating and divergent resource for selective oxidation and reduction in organic chemistry, generating activated species, for example radical anions or radical cations. In this review, we try to underscore usefulness of electrogenerated Michael addition reaction with the hope of encouraging synthetic organic chemists to contemplate it, as an efficient and green strategy when it is required in their designed multi-step reaction pathways.

Catalyst-Free One-Pot Three-Component Synthesis of Diversely Substituted 5-Aryl-2-oxo-/thioxo-2,3-dihydro-1H-benzo[6,7]chromeno[2,3-d]pyrimidine-4,6,11(5H)-triones Under Ambient Conditions

A simple, catalyst-free, straightforward, and highly efficient one-pot synthesis of pharmaceutically interesting diverse kind of a new series of functionalized 5-aryl-2-oxo-/thioxo-2,3-dihydro-1H-benzo[6,7]chromeno[2,3-d]pyrimidine-4,6,11(5H)-triones 4 (4-1-4-37) and substituted 5,5'-(1,4-phenylene)bis(2-oxo-/thioxo-2,3-dihydro-1H-benzo[6,7]chromeno[2,3-d]pyrimidine-4,6,11(5H)-trione) derivatives 4' (4'-1-4'-3) has been developed based on a three-component reaction between barbituric acid/N,N-dimethylbarbituric acid/2-thiobarbituric acid (1), aromatic aldehydes (2), and 2-hydroxy-1,4-naphthoquinone (3) in aqueous ethanol at room temperature (25-30 °C). The salient features of this protocol are mild reaction conditions, use of no catalyst, no need of column chromatographic purification, excellent yields, high atom economy, eco-friendliness, easy isolation of products, and reusability of reaction media.

Synthesis and Pharmacological Activities of Pyrano[2,3-d]pyrimidine and Pyrano[2,3-d]pyrimidine-5-one Derivatives as New Fused Heterocyclic Systems

Various fused oxazine such as 4-(4-methoxyphenyl)-3,7-dimethyl-1,4-dihydro-5H-pyrazolo [4′,3′:5,6]pyrano[2,3-d][1,3]oxazin-5-one2has been prepared and utilized as a starting material for novel pyrazolopyranopyrimidinones3,5,6, and7a–cand pyrazolopyranopyrimidines4,9,10, and11which are expected to possess considerable chemical and pharmacological activities. The structures of the new compounds have been elucidated by spectroscopic data and elemental analysis. The antioxidant and anticancer activities of synthesized products have been evaluated.

Recent applications of barbituric acid in multicomponent reactions

This review aims to show representative examples of multicomponent reactions utilizing barbituric acid in the synthesis of various heterocyclic structures.