Current Organic Chemistry - Volume 26, Issue 14, 2022

In the present era, the use of fused heterocyclic compounds has been showing considerable value in the development and designing of new drugs. Article flow through the synthetic strategies highlight the application of metal-free, visible light-mediated catalysis for the fusion of six-membered heterocyclic scaffolds containing nitrogen and sulfur heteroatoms. The power stratagem for the synthesis of diverse fused heterocyclic compounds is the sequencing of multicomponent reactions and subsequent cyclization reactions. The heterocyclic compounds containing Nitrogen and Sulphur atoms exhibit unique properties and are used as potential reactive materials in pharmacokinetic systems. These compounds can also be synthesized considering the high yield, low waste and green synthesis. The main aim of this review is to give an outlook on the synthetic feasibility of the fused heterocyclic system and to develop an innovative heterocyclic synthetic scheme that allows for different bond-forming strategies which are having a significant impact in the pharmaceutical industry, especially the pyrimido-thiazine derivatives in the future synthetic heterocyclic chemistry. The future of Heterocyclic chemistry is the development of robust synthetic routes which can generate a bulk quantity of desired products and accelerate the drug development process.

Coumaric acid is a hydroxy derivative of cinnamic acid with three different isomers (ortho, meta and para). Its most commonly available form is p-coumaric acid. p-Coumaric acid i.e., 4-hydroxycinnamic acid is a potent phenolic compound found to exist naturally in various plants, cereals, fruits and vegetables. It is one of the major constituent compounds of phenolic polymer lignin in lignocellulosic materials. Various natural and synthetic derivatives of pcoumaric acid have been reported in the literature. Different extraction methods including conventional methods such as solvent extraction, acidification, alkaline extraction etc. and recent approaches such as the clip-off method, sugaring out method, soft microwave extraction etc. for its qualitative and quantitative determination in various plant materials have been investigated by various researchers. This paper has discussed the synthesis of various derivatives of p-coumaric acid such as amides, esters, aldehydes, polymers, and copolymers. p-Coumaric acid and its derivatives have been found to possess different bioactive properties such as antioxidant, antimicrobial, anticancer, antiarthritic, anti-inflammatory, gout prevention, anti-diabetic, anti-melanogenic, skin regeneration, gastroprotective, anti-ulcer, cardioprotective, hepatoprotective, reno-protective, bone formation, anti-angiogenic and anti-platelet etc. Owing to this huge bioactive potential, p-coumaric acid could be incorporated in edible food products, pharmaceutical products, cosmetics, etc. More studies are required to evaluate their compatability in these products. To the best of our knowledge, this is the first review discussing natural occurrence, extraction, natural derivatives, synthesis of various derivatives and therapeutic applications of p-coumaric acid.

The reduction of different unsaturated compounds by transfer hydrogenation (TH) has emerged as a more efficient methodology than the classical method of using the molecular hydrogen in industry and laboratory. Transfer hydrogenation is more advantageous in terms of safety and convenience. Alcohols, formic acid, esters, H2O, etc. are the common molecules that are used as a hydrogen donor in the transfer hydrogenation reaction. Primary alcohols, namely methanol and ethanol were less explored as a hydrogen source in the TH reaction, probably due to the formation of aldehyde after dehydrogenation of these alcohols, which are more reactive and may undergo side reactions. However, methanol and ethanol are cheap, easily available, and easily handled compounds. They can be easily obtained from biomass, coal, etc. Because of these advantages, chemists became more interested in the application of methanol and ethanol as hydrogen sources in the transfer hydrogenation reaction. In this review, we present an overview of the work reported by different groups on the transfer hydrogenation reactions with methanol and ethanol as hydrogen sources.

Limonoids are the most representative metabolites present in the order Rutales, which includes the families Rutaceae, Meliaceae and Cneoraceae. They are tetranortriterpenoids with a 4,4,8-trimethyl-17-furanylsteroidal skeleton, containing several oxygenated functions. The Meliaceae family consists of 50 genera with more than 1400 species distributed in tropical and subtropical regions worldwide. Plants of this family are found to be rich in limonoids. Limonoids from the Meliaceae family exhibit a diverse range of cytotoxic, antioxidant, anti-inflammatory, antimicrobial, antimalarial, and antifeedant activities, some of which have been commercially used for different purposes. Numerous studies on limonoids from Meliaceae family and their bioactivities have been reported recently. This review covers limonoids' isolation and structure determination reported during 2012–2022. 1172 novel limonoids in 118 papers have been summarized. Furthermore, important biological activities of these limonoids have also been outlined. This review can provide useful information for medicinal and pesticidal chemistry and phytochemistry researchers who are interested in the chemistry and biology of limonoids.