Natural products, with their various sources from plants, marine organisms, and microorganisms, are considered a key source and inspiration for medicines and continue to be so. Indole alkaloids are a class of alkaloids and represent a large subunit of natural products. Indole alkaloids of biological importance are numerous and cover a wide range of pharmaceutical applications, including anticancer, antiviral, antimicrobial, anti-inflammatory, and antioxidant. Obtaining natural, biologically active indole compounds involves isolating them from their natural sources or preparing them synthetically. 3-Substituted indoles represent an emerging structural class of marine alkaloids based on their high degree of biological activity. 3-Acetyl indole is an important core used as a starting material for synthesizing many bioactive indole alkaloids. (5-Indole)oxazole alkaloids, β-carboline alkaloids, bis-indole alkaloids, chuangxinmycin, meridianine, and (±) indolemycin are the most important indole alkaloids that are prepared starting from 3-acety indole. The present review provides comprehensive information on the structures and the synthesis of bioactive indole alkaloids utilizing 3-acetyl indole and its derivatives as starting compounds. Additionally, it also spotlights the diverse biological activities of these compounds.

The triazine moiety holds a special and very important position in the field of medicinal chemistry owing to its enormous biological and pharmacological potential. Over eras, triazine scaffolds have been investigated for synthesizing novel molecules that may be used for the treatment of different types of pathological conditions, such as infections, cancer, inflammation etc. A vast number of lead molecules have been established from the triazine moiety. The triazine fused with numerous heterocyclic rings, such as pyrrole, benzimidazole, indole, imidazole, carbazole, etc., have formed various bicyclic with pharmacological actions. The triazines display a wide range of activities, and synthesizing various marketable medicines that hold triazine moiety has made the attention of chemists worldwide grow over the years in the moiety. In this review article, the commercially available compound containing triazine has been presented, and an attempt has been made to collect the works reported, mostly in the past decade, by numerous scientists, related to the structural differences amongst the triazine analogues giving antitumor, and antimicrobial and other activities. The objective of this review article was to outline the current information on triazines and their derivatives with respect to their biological potential and various pharmacological activities. The summary of this review article would be helpful and describe the function and activity of the moiety to bring up-to-date the scientists working in the direction of designing and synthesising novel lead molecules for the treatment of different types of disease with the current molecules that have been synthesized from the triazine scaffold.

Background: This work describes the oxidation of a catechol moiety to the corresponding qui-none by using Mn(III)-based catalysts in the presence of an organic base. Two newly reported Mn(III)-Schiff base complexes were utilized for the oxidation of three different substrates, namely, 3,5-di tert-butyl catechol, 1,4-dihydroxy benzene and pyrocatechol, aerobically. Objective: We intended to understand the role of a base for the above-mentioned oxidation process. Also, we were interested to monitor the progress of reaction using 1H-NMR spectroscopy and to get more insight into the mechanistic path of the reaction. Methods: The oxidation processes were studied in open air in acetonitrile or methanol solvent. The reaction mixture containing concerned substrate, catalyst, and base were stirred in open air and 1H-NMR spectrum was recorded using the crude reaction mixture in different time intervals. Results: Interestingly, introduction of a base in the reaction mixture, enhanced the rate to a great extent for the first two substrates. This observation may provide an idea toward the rate determining step of the pro-cess. Notably, the third substrate, pyrocatechol, could not be oxidized by any of the two catalysts even with a base. The oxidation of 1,4-dihydroxy benzene may emphasize monodentate binding mode of the sub-strate. Each of the oxidation was monitored with the help of time dependent 1H-NMR spectroscopy. Conclusion: A mechanistic pathway has been proposed. The spectra obtained in different cases help to compare the efficiency of the catalysts with or without base. In the absence of the catalysts, triethylamine alone cannot complete the conversion in the stipulated time, which may establish the effectiveness of the catalysts via the base-assisted mechanism.

: Polyethylene glycol (PEG) has become a popular solvent and green catalyst for a variety of chemical reactions. It is a stable and biodegradable polymeric catalyst used in organic synthesis because it may be recycled numerous times without significantly losing its catalytic activity. Recently, the use of PEG-H2O mixed solvent systems in organic synthesis has gained popularity. : This article presents an overview of PEG-H2O solvent system-mediated organic reactions, with a main focus on the importance of the solvent system. The study also focuses on recent developments in the PEG-H2O solvent system-mediated synthesis of a number of heterocyclic compounds : Important characteristics of these PEG-H2O solvent systems include high atom economies, gentle reaction conditions, faster reaction rates, readily isolated side products and high yields. Results from various reactions showed that the choice of proper ratio of PEG: H2O solvent system plays a key role in product yields.

Background: Condensation of 3-acetyl coumarin (1) with 2‐(4-methoxy- benzylidene) malononitrile (2) in ammonium acetate/acetic acid or absolute ethanol/piperidine affords pyridine (3) and chromen-2-one (4) derivatives, respectively. Methods: In this study, the reaction of 3 with an electrophilic reagent, namely, formic acid, acetic anhydride and formamide afforded the pyridopyrimidinone and pyridine derivatives (6- 9). Also, treatment of 3 with different aromatic aldehydes, carbon disulfide, NaN3/NH4Cl, 2- (4-methoxybenzylidene)malononitrile and acetophenone afforded pyridopyrimidinone, carbamodithioic acid, tetrazol-5-yl-chromen-2-one, 2H-chromen-2-one, and pyridine derivatives (10-14), respectively. Results: This study synthesized coumarins with antimicrobial activity and verified the structure and purity of the synthesized compounds using spectral data. Conclusion: The new compounds were evaluated in vitro for their antimicrobial activity against gram-positive bacteria (Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus) and gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa), in addition to fungus (Candida albicans). The investigated substances 3 and 14 presented good activity against MRSA, E. coli, P. aeruginosa and C. albicans, while compounds 9, 10a-c, 11, 12 and 13 exhibited good to moderate activity.

: Some new (S)-2-[1-aryl-5-methyl-1H-1,2,3-triazol-4-yl]-4-benzyl-4,5-dihydro-ox-azoline were synthesized by the reaction of (S)-N-(1-hydroxy-3-phenylpropan-2-yl)-1-aryl-5-methyl-1H-1,2,3-triazole-4-carboxamides which were prepared from aromatic amine as start-ing materials, with p-toluenesulfonyl chloride, triethylamine and DMAP. The structures were characterized by 1H NMR, 13C NMR, MS and IR. The synthesized chiral triazole-oxazoline was used as a ligand in the Diels-Alder asymmetric catalytic reaction between 3-allyl-1,3-ox-azolidin-2-ketone and 2-methyl-1,3-butadiene, using PdCl2 as catalyst. (S)-3-(4-methylcyclo-hexe-3-ene-1-formyl)-1,3-oxazolidin-2-one was obtained. Background: The chiral triazole-oxazoline ligands are rarely reported. Objective: The aim of the study was to synthsize some new chiral triazole-oxazoline ligands (S)-4-benzyl-2-(1-aryl-5-methyl-1H-1,2,3-triazole-4-yl)-4,5-dihydrooxazoline (5a-g). Methods: The one-pot methods of oriented synthesis were adopted. This study provides a sim-ple and effective method for the synthesis of new chiral triazole-oxazoline derivatives. Results: The some new chiral the triazole-oxazoline ligands (S)-4-benzyl-2-(1-aryl-5-methyl-1H-1,2,3-triazole-4-yl)-4,5-dihydrooxazoline (5a-g) were synthesized and the asymmetric Diels-Alder cyclization of 3-allyl-1,3-oxazolidin-2-ketone and 2-methyl-1,3-butadiene was catalyzed by PdCl2 using the synthesized (S)-4-triazole-oxazoline ligands. Conclusion: Some new (S)-4-benzyl-2-(1-aryl-5-methyl-1H-1,2,3-triazole-4-yl)-4,5-dihydro-oxazoline was synthesized by corresponding N-[(S)-1-hydroxy-3-phenylpropan-2-yl]-1-aryl-5-methyl-1H-1,2,3-triazole-4-formamide, through one-pot oriented synthesis method. After preliminary evaluation, the chiral triazoline-oxazoline ligands, in which 1,2,3-triazole rings, like pyridine-type rings, chiral materials were saved and replace one oxazoline ring in the di-oxazoline ligands for asymmetric catalytic reactions.

There are different approaches to the synthesis of benzimidazole. In this article, five new benzimidazole derivatives, BMPO, Me-BMPO, Di-MeBMPO, F-BMPO and Cl-BMPO where (BMPO=3-[(1H)-benzo[d]imidazol-2-yl]pyridin-2(1H)-one), have been prepared. Another study was carried out on luminescence properties and their potential applications for the detection of transition metal ions. From the one-pot synthesis approach, all the derivatives of the benzimidazole compounds were obtained. The compounds were characterized using HRMS, 1HNMR, 13CNMR, and X-ray crystallography. Herein, a mechanism has been deciphered by predicting the release of HCl(g). All compounds showed a strong deep blue emission when dissolved in dimethylacetamide (DMA), with emission wavelengths at 423, 428, 435, 423, and 421 nm, and half-times of 3.64, 2.77, 2, 19, 3.42 and 3.52 ns, respectively. In addition, their emission quantum yields were determined to be 72, 50, 42, 73 and 80%. Five new benzimidazole derivatives, BMPO, Me-BMPO, Di-MeBIPO, F-BIPO, and Cl-BIPO, have been successfully synthesized by the one-pot synthesis method, and their structures are characterized and confirmed. The compounds exhibited exceptional luminescence by emitting a strong blue light in DMA with high fluorescence quantum yields between 42~80%.

As a novel and environmentally friendly Brönsted acid, imidazole hydrochloride was used to promote the synthesis of 2,3-disubstituted-4(3H)-quinazolinone from o-aminobenzoic acid and DMF derivatives. The essence of this reaction is a multicomponent reaction, which constructs multiple chemical bonds between different components through the transamidation of imidazole hydrochloride. This protocol showed a wide range of functional group tolerance, and a series of quinazolinones were synthesized in low to moderate yields without metal catalysts, oxidants or other additives.

In order to study on structure-activity relationships of benzofurans. Benzofuran is a kind of natural compound widely existing in nature with pharmacological effects. The development of new anticancer benzofuran derivatives has attracted more and more attention. We have introduced an active quinazoline unit into piperazine-substituted benzofuran, prepared a series of quinazoline-benzofuran compounds, and evaluated cytotoxic activity against a panel of human tumor cell lines by MTT assay. 48 novel quinazoline-substituted benzofuran derivatives have been prepared, and in vitro, cytotoxic activity against five human tumor cell lines was evaluated. The results indicated that some quinazoline-benzofuran conjugates showed selective inhibitory activity against tumor cell lines. We have found that compound 14x displayed excellent cytotoxic activity, which could be considered a potential anticancer agent.