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A simple and efficient one-pot two-step synthesis of substituted 3-aminoarylquinolines has been achieved from 2-nitrobenzaldehyde and indoles under microwave irradiation. Firstly 2-nitrobenzaldehydes is reduced to 2-aminobenzaldehyde in situ by commonly used chemo selective reductant SnCl2 followed by condensation of indole. The acidic nature of the resultant reaction mixture due to SnCl2 helps in the condensation and facile ring opening of indole leading to the formation of 3-aminoarylquinoline derivatives in good to moderate yields.

An unprecedented Pd-catalyzed intramolecular Heck cyclization has been investigated on halogenated diene scaffolds undergoing various mode of cyclization and termination leading to the formation of structurally differing fused cyclopenta(e)none and aromatic analogue. The discrimination in the fate of palladium intermediates formed in situ undergoing Heck cyclization preferentially arises out of the difference in reaction temperature as well as substrate architecture. Sequential Heck reaction of 1-Bromo-5-methyl-1-aryl-hexa-1,5-dien-3-ol derivatives followed by oxidation or termination via sp2 C H activation in aromatic ring led to the formation of fused cyclopentanes. However, the similar reaction at elevated temperature showed predominance towards the formation of aromatic analogues via one pot cyclization and dehydroxylation. The mechanism for the formation of cyclopentanone fused with cyclopropane ring system is supported by density functional theory based calculations.

A fluorescent and colorimetric cyanide sensor (4-Br) based on the activated C-H group to conscruct a FRET platform has been described for the first time, along with demonstration of selective and reversible detection of cyanides through it. The sensing mechanism of 4-Br is an integration of ICT and FRET mechanisms, based on the deprotonation of the activated C-H group. Importantly, it is suitable for fluorescence imaging of cyanides in living cell.

Here, we report a simple and useful strategy for a series of C-3-symmetric pi-conjugated and highly soluble spiro-annulated truxene derivatives. The role of substituent at C5, C10, C15, C2, C7, and C12 positions was studied. We observed that truxenes containing carbonyl groups showed red shift in the absorption maxima in comparison with compounds devoid of carbonyl group. Enhanced conjugation in these systems may be responsible for this red shift. It was observed that truxene derivatives with carbonyl moiety exhibited faster decay than other derivatives. Benzyl groups play some role in the excited state dynamics as decay becomes slower when the spiro moiety was replaced by benzyl group at C5, C10, and C15 positions. Additionally, we noticed the highest quantum yield in t-butanol solvent and least in acetonitrile. (C) 2018 Published by Elsevier Ltd.

A convenient and precise nitration and oximation of alkenes with tert-butyl nitrite has been reported, yielding α-nitro ketoximes in satisfactory yields with broad substrate generality and excellent stereoselectivity under mild conditions. Experiments indicate that tert-butyl nitrite serves as both NO and NO2 sources and water plays a key role in this difunctionalization reaction.

An efficient and green approach has been developed for the construction of Tetracyclic nitrogen-bridgehead compounds were designed and synthesized in good yields. The reaction of easily prepared 3-bromoisobenzofuran-1(3 H )-one with isatoic anhydride and amines gave the desired isoindoloquinazolinone derivatives in moderate to good yields. It is also amenable for scale-up.

Graphical abstract We report the in silico studies and ultrasound assisted Cu-catalyzed synthesis of 3-alkynyl substituted 2-chloroquinoxaline derivatives as potential ligands for N-protein of SARS-CoV-2., Highlights • In silico studies were performed using 3-alkynyl 2-chloroquinoxalines. • These compounds were assessed as ligands for N-protein of SARS-CoV-2. • Their synthesis involved Cu-catalyzed coupling under ultrasound irradiation. • In silico studies established a virtual SAR within the series. • Three compounds appeared as potential agents for further studies., In view of recent global pandemic the 3-alkynyl substituted 2-chloroquinoxaline framework has been explored as a potential template for the design of molecules targeting COVID-19. Initial in silico studies of representative compounds to assess their binding affinities via docking into the N-terminal RNA-binding domain (NTD) of N-protein of SARS-CoV-2 prompted further study of these molecules. Thus building of a small library of molecules based on the said template became essential for this purpose. Accordingly, a convenient and environmentally safer method has been developed for the rapid synthesis of 3-alkynyl substituted 2-chloroquinoxaline derivatives under Cu-catalysis assisted by ultrasound. This simple and straightforward method involved the coupling of 2,3-dichloroquinoxaline with commercially available terminal alkynes in the presence of CuI, PPh3 and K2CO3 in PEG-400. Further in silico studies revealed some remarkable observations and established a virtual SAR (Structure Activity Relationship) within the series. Three compounds appeared as potential agents for further studies.

Graphical abstract, Remdesivir, the first drug approved by the FDA to treat COVID-19, is in high demand for patients infected with the SARS-CoV-2 virus. Herein, we report a facile approach minimizing the protecting group manipulations to afford remdesivir in good overall yield.

Bis-morpholinophosphorylchloride (Bmpc), in the presence of a base, is an efficient dehydrating agent for both aromatic and aliphatic primary amides, and gives corresponding nitriles under mild conditions in god yields and purity. During the reaction the enantiomeric integrity remains intact.

The Baylis-Hillman (BH) reaction plays a fascinating role in the field of synthetic and medicinal chemistry. BH adducts and their derivatives have been used as crucial synthons for the synthesis of various pharmaceutically useful natural products and compounds with carbocyclic or heterocyclic frameworks. This digest letter aims to discuss some key ideas for the synthesis of biologically active scaffolds using BH reaction and raise the awareness of this emerging research domain in modern drug discovery. In this review, we will present and discuss recent reports of various biologically active scaffolds derived from BH reaction, and their reported biological activities.

The first total syntheses of naturally occurring cyclodepsipeptides Hikiamides A–C are described. The key linear pentapeptide precursors, prepared efficiently via Fmoc-solid-phase synthesis, were cyclized in dilute solution to provide the target Hikiamides A–C. The structures of the synthetic Hikiamides A–C were characterized by NMR and HRMS spectroscopy which were in agreement with those of natural products.