A green protocol for one-pot three-component synthesis of 1-(benzothiazolylamino) methyl-2-naphthol catalyzed by oxalic acid

Synthesis, biological evaluation, theoretical calculations, QSAR and molecular docking studies of novel arylaminonaphthols as potent antioxidants and BChE inhibitors

A completely green protocol was developed for the synthesis of a series of arylaminonaphthol derivatives in the presence of N-ethylethanolamine (NEEA) as a catalyst under ultrasonic irradiation and solventless conditions. The major assets of this methodology were the use of non-toxic organic medium, available catalyst, mild reaction condition, and good to excellent yield of desired products. All of the synthesized products were screened for their in vitro antioxidant activity using DPPH, ABTS, and Ferric-phenanthroline assays and it was found that most of them are potent antioxidant agents. Also, their butyrylcholinesterase inhibitory activity has been investigated in vitro. All tested compounds exhibited potential inhibitory activity toward BuChE when compared to standard reference drug galantamine, however, compounds 4r, 4u, 4 g and 4x gave higher butyrylcholinesterase inhibitory with IC50 values of 14.78 ± 0.65 µM, 16.18 ± 0.50 µM, 20.00 ± 0.50 µM, and 20.28 ± 0.08 µM respectively. On the other hand, we employed density functional theory (DFT), calculations to analyze molecular geometry and global reactivity descriptors, and MESP analysis to predict electrophilic and nucleophilic attacks. A quantitative structure-activity relationship (QSAR) investigation was conducted on the antioxidant and butyrylcholinesterase properties of 25 arylaminonaphthol derivatives, resulting in robust and satisfactory models. To evaluate their anti-Alzheimer's activity, compounds 4 g, 4q, 4r, 4u, and 4x underwent docking simulations at the active site of the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), revealing why these compounds displayed superior activity, consistent with the biological findings.

An efficient catalysis for the synthesis of pyrimido[1,2-a]benzimidazoles and 1-(benzothiazolylamino)methyl-2-naphthols using ZnO@SO3H@Tropine

In this research and in the line of our researches on the use of nano-substrates modified with ionic liquid in organic reactions, an efficient and green method for the one-pot three-component synthesis of pyrimido[1,2-a]benzimidazole and 1-(benzothiazolylamino)methyl-2-naphthol derivatives is reported using a new nanoporous catalyst formulated as ZnO@SO3H@Tropine. Further analysis of the catalyst for its characterization has been performed using thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and Fourier-transform infrared spectroscopy (FT-IR). The present approach creates a variety of biologically active heterocyclic compounds with excellent yields and short reaction times. Among the other advantages of the current method are: ease of operation, clean reaction profiles and ease of separation. Also, this catalyst can be reused five times without loss of its catalytic activity.

One-pot synthesis of 1-(benzothiazolylamino)aryl methyl-2-naphthols and 3-benzothiazolyl 2,3-dihydroquinazolinones using a magnetically recoverable core–shell nanocomposite as catalyst

Nano-magnetite-supported sulfated polyethylene glycol (Fe3O4@PEG-SO3H) was prepared, characterized and utilized as a magnetically recoverable heterogeneous catalyst for the one-pot, three-component reaction of 2-aminobenzothiazole, aldehydes and 2-naphthol/isatoic anhydride resulting in efficient formation of 1-(benzothiazolylamino)arylmethyl-2-naphthol or dihydroquinazolinones derivatives. The significant features of this method include green conditions, operational simplicity, minimizing production of chemical waste, shorter reaction times and good to high yields. In addition, the nanocatalyst can easily be separated from the reaction mixture by application of a magnetic field and reused without significant deterioration in its catalytic activity.

α-Aminoazoles/azines: key reaction partners for multicomponent reactions

Aromatic α-aminoazaheterocycles are the focus of significant investigations and exploration by researchers owing to their key role in diverse biological and physiological processes. The existence of their derivatives in numerous drugs and alkaloids is due to their heterocyclic nitrogenous nature. Therefore, the synthesis of a structurally diverse range of their derivatives through simple and convenient methods represents a vital field of synthetic organic chemistry. Multicomponent reactions (MCRs) provide a platform to introduce desirable structure diversity and complexity into a molecule in a single operation with a significant reduction in the use of harmful organic waste, and hence have attracted particular attention as an excellent tool to access these derivatives. This review covers the advances made from 2010 to the beginning of 2020 in terms of the utilization of α-aminoazaheterocycles as synthetic precursors in MCRs.

Recent advances in the synthesis and synthetic applications of Betti base (aminoalkylnaphthol) and bis-Betti base derivatives

The multicomponent reaction between 2-naphthol, arylaldehydes and ammonia yields aminobenzylnaphthols in a process known as the Betti reaction, which was first uncovered at the beginning of the 20th century. Various methods have been reported for the synthesis of aminobenzylnaphthol (Betti base) and bis-Betti base derivatives using various types of naphthols, aromatic amines, heteroaromatic amines, and aliphatic and cyclic amines instead of ammonia or diamines and aliphatic and aromatic aldehydes or dialdehyde compounds under various conditions in recent years. The Betti reaction produces racemic and non-racemic aminobenzylnaphthol ligands. It is also clear that the most important area of application of the non-racemic aminonaphthols prepared in this manner is their use in asymmetric synthesis, either as chiral ligands or as chiral auxiliaries. The functional groups in these Mannich products offer many ring closure possibilities. Some of these products or the starting bifunctional compounds possess biological activity. Herein, we present a selection of the relevant studies on this topic.

Contemporary progress in the synthesis and reactions of 2-aminobenzothiazole: a review

Various protocols for the synthesis and reactions of 2-aminobenzothiazole.