The reactivity of N-Heterocyclic carbene (NHC)-bound alkynyl acyl azoliums was under explored in chemistry. We herein reported an NHC-catalyzed [3+3] annulation of alkynyl acyl azoliums with β-keto esters. The strategy features mild reaction conditions and exhibits broad substrates scope, delivering a wide range of tri-substituted α-pyrones in moderate to excellent yields (up to 95%). This approach extends the reactivity of alkynyl acyl azoliums to β-keto esters binucleophiles.

Pd-Catalyzed switchable access to imines and amines from secondary alcohols. Pd(OAc)2 catalyzes the challenging synthesis of imines through acceptorless alcohol dehydrogenation using secondary alcohols and amines. Interestingly, when the catalytic reaction is performed in a closed system, in the presence of base, the reaction selectively yields the corresponding amine.

Naphthoquinone-based enediynes were synthesized using a simple Sonogashira coupling reaction for achieving fast generation of radical species under physiological condition through a cascade rearrangement and cycloaromatization pathway and high cytotoxicity to tumor cell lines.

Natural products isolation studies were performed on Dodonaea filiformis leaf material and Dodonaea viscosa flowers. In total, seven prenylated flavonoids, two clerodane and seven ent-labdane diterpenoids, and two flavonoids were isolated. Four of these compounds are previously unreported, including two prenylated flavonoids bearing malonic acid moieties.

A direct copper-catalyzed C−H bond oxidative sulfonylation of β-alkyl cyanoalkenes with sodium sulfinates was reported. The proposed mechanism suggests the existence of potential equilibrium between cyanoalkenes and allylic cyanoalkyl compounds, and the isomeric allylic cyanoalkyl compounds, due to their higher electron density, readily undergo addition reactions with sulfonyl radicals to selective afford cyanoallylic sulfones.

A facile and efficient synthesis of polysubstituted imidazolidin-2-ones has been developed via an oxidative cyclization of activated acetyl amides and cyclic amidines mediated by iodosobenzene (PhIO). A mechanism was proposed for this transformation, which involves sequential intermolecular addition, Hofmann-type rearrangement and intramolecular cyclization reactions. The novel protocol features readily available starting materials, mild reaction conditions, simple execution, metal-free oxidative cyclization, and one-pot procedure.

Metal-loaded titanium dioxide (M/TiO2) promotes N-methylation of twenty kinds of α-amino acid motifs found in proteins in the human body with methanol. The attractive features of the present synthetic protocol include mild reaction conditions, high atom economy, and easy procedures.

A novel and eco-friendly technique for the synthesis of C–3 nitro derivatives of 4-quinolones via the regioselective C(sp2)–H bond functionalization employing tert-butyl nitrite as nitrating agent in presence of TEMPO [(2,2,6,6-tetramethylpiperidin-1-yl)oxyl] as an oxidant is unfolded herein. The protocol is scalable as well as high yielding with wide substrate scope and broad functional group tolerance. In-depth mechanistic investigations revealed that the reaction occurred through a free radical pathway. The nitro derivatives of 4-quinlones were selectively reduced to corresponding aminated 4-quinolones. Finally, the photo-physical properties of synthesized amine derivatives were also investigated, and some of them showed good fluorescence properties.

The reaction of carbon dioxide (CO2) with epoxide to generate cyclic carbonates is one of the most effective chemical fixation methods.

We have developed an efficient visible light induced copper-mediated protocol to synthesize conjugated 1,3-diynes via decarboxylative homocoupling of arylpropiolic acids. A variety of electron-rich and electron-deficient acids worked well in this methodology providing desired product upto 99% yield. Detailed mechanistic investigations including UV-vis spectroscopy and in-situ IR experiments have been carried out to elucidate the plausible reaction mechanism. Compared to previously reported thermal strategies, this new pathway occurs at room temperature, employs greener solvent and arial oxygen as an oxidant.

An efficient approach towards the synthesis of substituted spirochromans and dihydrocoumarins from a three-component reaction involving aromatic aldehydes, phenols and phenylene dithiolanes is described. This FeCl3 catalyzed reaction utilizes either aromatic aldehydes or their acetals for condensation with phenols to generate o-quinone methides in situ which further undergo a formal [4+2] cyclization with phenylene dithiolanes. Careful control of temperature allows direct access to dihydrocoumarins by the removal of the thioacetal moiety.

Biodegradable plastics synthesized from chiral organic acids have the potential to replace petroleum-based plastics. Poly[(R)-3-hydroxybutyric acid] is highly biodegradable, but have poor thermal properties. Copolymerization of (R)-3-hydroxybutyric acid with l-lactic acid as monomers improved the thermal properties while maintaining its excellent biodegradability. Copolymers with a high (R)-3-hydroxybutyric acid unit ratio degraded well in activated sludge.

Here we report several useful synthetic strategies to azepino hi-indoles, that are structural units in natural products by using commercially available indole derivatives such as 7-bromo indole and 7-formylindole via palladium catalyzed cross-coupling reaction, ring closing olefin metathesis (RCM) as key steps. Later, we extended this strategy to seven-membered fused indoles containing dioxano and dioxocano derivatives via allylation, double bond isomerization and RCM sequence. Additionally, azepino indole having diene moiety was obtained by enyne metathesis and shown to be useful for Diels-Alder strategy. Along similar lines, we also report eight-membered fused azocino indole using Grignard reaction and RCM as key steps and we demonstrated that the product obtained is useful for Fischer indolization to obtain bis-indole derivative. Here several synthetically useful transformations were performed to generate diversity in the fused indole derivatives. All the compounds synthesized here are well characterized by NMR and HRMS data.

Internally-bridged octaphyrin(1.1.1.1.1.1.1.1) was transformed to directly-linked porphyrin−pyricorrole hybrid upon NiII complexation. The structure has been unambiguously revealed by X-ray diffraction analysis. The pyricorrole skeleton is different from that reported earlier with regard to the position of pyridine moiety. The new pyricorrole macrocycle was characterized as an aromatic molecule, but its NiII complex is thermodynamically more stable as compared with parent NiII porphyrin.

This review provides a summary of electrosynthesis methods that can be used as an alternative method for synthesis of complex organic molecules in pharmaceutical and biological applications. This method involves electro-organic reactions occurring at room temperature and normal pressure through transferring electrons. Combining electrosynthesis with multi-component reactions (MCRs) can yield cost-efficient and environmentally friendly ways of synthesizing electrophilic substrates, bases, and nucleophiles in situ, making heterocycles more accessible.

A simple and user-friendly procedure is presented that allows the synthesis of N-substituted glutarimides with yields up to 88 % and chromatographic purity up to 99 %. The reaction does not require an inert medium or catalysts, which simplifies the process of product isolation and purification. In addition, the reaction is completed in 50–120 minutes, which makes it even more attractive.

Herein, we report a novel synthetic pathway for synthesizing bis-coumarins using 5 mol% [BCMIM][Cl] ionic liquid via the facile, one-pot, metal-free synthesis in aqueous ethanol at room temperature. A series of 24 derivatives were furnished in up to 94% yields in 15 min to 1.5 h and were characterized using different spectroscopic techniques. The photophysical properties of bis-coumarin derivatives were explored through UV-Visible and fluorescence spectroscopy. The absorption and emission spectra demonstrate a peak wavelength (λmax), within the range of 297 ̶ 311 nm and 486 ̶ 505 nm, respectively. An analogous pattern to the experimental results is seen in density functional calculations. The binding affinities of all the synthesised derivatives with Bovine Serum Albumin (BSA) were determined using AutoDock Vina which exhibited a range from -8.4 to -11.5 kcal mol-1. The computed binding constant (KBSA) by tryptophan (Trp) emission quenching values illustrate strong binding interactions of the selected ligands in the order of 104. The calculated binding affinities were validated by performing molecular dynamics simulations of the best docking pose using GROMACS software over a period of 1 ns for studying the stability of protein-ligand complexes.

A nickel-catalyzed migratory cycloisomerization of o-alkynylanilides was investigated, and it was found to give 2,3-disubstituted indoles. The cyclization was thought to proceed via an aza-nickelcyclepentene intermediate formed from alkyne and the C=O bond amide moiety in the substrate, accompanied by acyl transfer on the nitrogen atom to the C3 position in the product.

A LiBr-mediated cross-coupling reaction between organozinc reagents and α-chloro trifluoromethyl amines for modular access to α-trifluoromethyl amines is reported. Different kinds of alkyl- and arylzinc reagents are compatible with this LiBr-mediated cross-coupling, resulting in a number of diversified α-trifluoromethyl amines in high yields. This method features easy operation, mild reaction conditions, excellent functional group tolerance, and broad substrate scope. Preliminary mechanistic insight suggests that this cross-coupling reaction involves α-trifluoromethyl imine formation from α-chloro trifluoromethyl amines under LiX (X= Cl, Br). The synthetic utility of this method is successfully demonstrated by a gram-scale reaction and diverse product transformations.

Gold-alkyne partnership has emerged as a powerful tool for constructing heterocyclic scaffolds. This review summarizes recent advances (2018–2023) toward the synthesis of indole skeletons via gold-catalyzed annulations of various alkynes.