Total synthesis of atropodiastereomers of heterodimeric alkaloids: narcipavline and narcikachnine.

We report the first asymmetric total synthesis of recently isolated heterodimeric alkaloids, narcipavlines A (1a) and B (1b), and narcikachnines A (2a) and B (2b), thereby confirming their absolute stereochemistry. These alkaloids showcase a unique heterodimeric structure, amalgamating two distinct types of alkaloids: the -hydrodibenzofuran containing tetracyclic galantamine core (6a) and the galanthindole core (7) featuring a biaryl axis. The presence of this biaryl axis, coupled with the substantial galantamine core (6a) at the substituents, imposes constraints on free rotation around the C-C axis, resulting in atropisomerism, an exceedingly rare phenomenon in nature.

Total synthesis of bicyclomahanimbine by Cu(ii)-promoted photoredox process.

Since the isolation of carbazole alkaloids, the synthetic chemists have witnessed an upsurge in research of them due to their potential pharmacological properties. Our approach shows the total syntheses of five such biorelevant pyrano-[3,2]-carbazole alkaloids, emphasizing biomimetic and innovative synthetic methodologies such as cascade reactions and strategic bond formations through sustainable electrochemical and photochemical conditions.

2D organic nanosheets of self-assembled guanidinium derivative for efficient single sodium-ion conduction: rationalizing morphology editing and ion conduction.

The resurgence of interest in sodium-ion batteries (SIBs) is largely driven by their natural abundance and favourable cost, apart from their comparable electrochemical performance when compared with lithium-ion batteries (LIBs). The uneven geographic distribution of the raw materials required for LIBs has also contributed to this. The solid-state electrolyte (SSE) is typically one of the vital components for energy storage in SIBs and for achieving high electrochemical performances.

Total synthesis of (-)-2-oxo epimesembranol and (+)-dihydromaritidine a key Johnson-Claisen rearrangement.

A general approach to alkaloids of the family following a key Johnson (orthoester)-Claisen rearrangement of an enantioenriched allylic alcohol has been disclosed. The tricyclic core (1c) of -3-octahydroindoline skeleton was achieved an ester-aminolysis followed by an intramolecular aza-Michael reaction with amine under elevated temperature. Utilizing aforementioned strategy, a collective total syntheses of alkaloids, such as (-)-2-oxo-epimesembranol (1d) [the first total synthesis], (-)-6-epimesembranol (1b), and (-)-mesembrine (1a) were shown.

Biomimetic total synthesis of the reported structure of (+)-selaginedorffone B.

The first enantioselective total synthesis of the reported structure of the structurally unique aromatic tetraterpenoid of anti-cancer potential, (+)-selaginedorffone B (2), has been accomplished from two modified abietane diterpenoids through an intermolecular Diels-Alder reaction between a bio-inspired diene 3 (HOMO counterpart) and dienophile 4 (corresponding LUMO counterpart) in a 23-step sequence, whereas the core framework of the monomeric abietane diterpenoid was constructed alkyne-activated ene-cyclization. Computational analysis was conducted to reveal the intricate regio and diastereoselectivity of this novel Diels-Alder reaction, strengthening the experimental results. The absolute configuration of the synthesized molecule was validated through X-ray studies of late-stage intermediates as well as comprehensive 2D NMR analysis.

Manganese catalyzed chemo-selective synthesis of acyl cyclopentenes: a combined experimental and computational investigation.

Cyclopentenes serve as foundational structures in numerous natural products and pharmaceuticals. Consequently, the pursuit of innovative synthetic approaches to complement existing protocols is of paramount importance. In this context, we present a novel synthesis route for acyl cyclopentenes through a cascade reaction involving an acceptorless-dehydrogenative coupling of cyclopropyl methanol with methyl ketone, followed by a radical-initiated ring expansion rearrangement of the formed vinyl cyclopropenone intermediate.

Total synthesis of naturally occurring abietane diterpenoids a late-stage Fe(iii)-TAML catalysed Csp-H functionalization.

The synthesis of diverse -fused decalins, including the abietane diterpenoids scaffold, using an efficient selective oxidation strategy is described. The abietane core was demonstrated to be a versatile scaffold that can be site-selectively functionalized. The utility of this novel oxidation strategy was showcased in a concise total synthesis of six abietane congeners.

Ambient stable solution-processed organic field effect transistors from electron deficient planar aromatics: effect of end-groups on ambient stability.

Ambient stable solution processed n-channel organic field effect transistors (OFETs) are essential for next-generation low-cost organic electronic devices. Several molecular features, such as suitable orbital energy levels, easy synthetic steps, , must be considered while designing efficient active layer materials. Here, we report a case of improved ambient stability of solution-processed n-type OFETs upon suitable end-groups substitution of the active layer materials.

Catalytic acceptorless dehydrogenative borylation of styrenes enabled by a molecularly defined manganese complex.

In this study, we employed a 3d metal complex as a catalyst to synthesize alkenyl boronate esters through the dehydrogenative coupling of styrenes and pinacolborane. The process generates hydrogen gas as the sole byproduct without requiring an acceptor, rendering it environmentally friendly and atom-efficient. This methodology demonstrated exceptional selectivity for dehydrogenative borylation over direct hydroboration.

Rejuvenation of dearomative cycloaddition reactions visible light energy transfer catalysis.

Dearomative cycloaddition is a powerful technique to access sp-rich three-dimensional structural motifs from simple flat, aromatic feedstock. The building-up of unprecedentedly diverse polycyclic scaffolds with increased saturation and stereochemical information having various applications ranging from pharmaceutical to material sciences, is an essential goal in organic chemistry. However, the requirement of large energy inputs to disrupt the aromaticity of an arene moiety necessitates harsh reaction conditions for ground state dearomative cycloaddition.

Natural surfactant mediated bioremediation approaches for contaminated soil.

The treatment of environmental pollution by employing microorganisms is a promising technology, termed bioremediation, which has several advantages over the other established conventional remediation techniques. Consequently, there is an urgent inevitability to develop pragmatic techniques for bioremediation, accompanied by the potency of detoxifying soil environments completely. The bioremediation of contaminated soils has been shown to be an alternative that could be an economically viable way to restore polluted soil.

Effects of microRNA-mediated negative feedback on gene expression noise.

MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression post-transcriptionally in eukaryotes by binding with target mRNAs and preventing translation. miRNA-mediated feedback motifs are ubiquitous in various genetic networks that control cellular decision making. A key question is how such a feedback mechanism may affect gene expression noise.

Divergent Synthesis of Chelating Aziridines and Cyclic(Alkyl)(Amino)Carbenes (CAACs) from Pyridyl-Tethered Robust Azomethine Ylides.

Azomethine ylides are typically in situ generated synthons for making N-heterocycles through cycloaddition reactions. But an offbeat aspect about them is the isomeric nature of aldiminium-based azomethine ylides and (alkyl/aryl)(amino)carbenes, interconvertible by a formal 1,3-H transfer. Herein, two thermally robust azomethine ylides with a N-appended picolyl sidearm are isolated, which cyclize to aziridines at 80 °C but unprecedentedly result CAAC-CuCl (CAAC=cyclic(alkyl)(amino)carbene) complexes when heated with CuCl at merely 60 °C.

A π-conjugated covalent organic framework enables interlocked nickel/photoredox catalysis for light-harvesting cross-coupling reactions.

Covalent organic frameworks (COFs) are an outstanding platform for heterogeneous photocatalysis. Herein, we synthesized a pyrene-based two-dimensional C[double bond, length as m-dash]C linked π-conjugated COF Knoevenagel condensation and anchored Ni(ii)-centers through bipyridine moieties. Instead of traditional dual metallaphotoredox catalysis, the mono-metal decorated Ni@Bpy-spc-COF interlocked the catalysis mediated by light and the transition metal.

Engineered vitamin E-tethered non-immunogenic facial lipopeptide for developing improved siRNA based combination therapy against metastatic breast cancer.

RNA interference based therapeutic gene silencing is an emerging platform for managing highly metastatic breast cancer. Cytosolic delivery of functional siRNA remains the key obstacle for efficient RNAi therapy. To overcome the challenges of siRNA delivery, we have engineered a vitamin E-tethered, short, optimum protease stabilized facial lipopeptide based non-immunogenic, biocompatible siRNA transporter to facilitate the clinical translation in future.

Hierarchical covalent organic framework-foam for multi-enzyme tandem catalysis.

Covalent organic frameworks (COFs) are ideal host matrices for biomolecule immobilization and biocatalysis due to their high porosity, various functionalities, and structural robustness. However, the porosity of COFs is limited to the micropore dimension, which restricts the immobilization of enzymes with large volumes and obstructs substrate flow during enzyme catalysis. A hierarchical 3D nanostructure possessing micro-, meso-, and macroporosity could be a beneficial host matrix for such enzyme catalysis.

Efficient light harvesting in self-assembled organic luminescent nanotubes.

Luminescent organic nanotubes derived from the co-assembly of cyanostilbene (CS) based cationic supramolecular polymers and bio-polyanion heparin, a known anticoagulant, have been utilized as highly efficient FRET (fluorescence resonance energy transfer) donors in aqueous media resulting in amplified acceptor emission in the orange-red and near-infrared (NIR). Energy transfer efficiencies higher than 80% and an ultra-high antenna effect of 150 were achieved even at high donor/acceptor ratios (500 : 1-100 : 1) translating to emission quenching of several hundred donors by one acceptor. Utilizing the temperature responsiveness of the FRET process, these systems were employed as ratiometric emission thermometers in the temperature range 20-90 °C.

A Donor-Acceptor Cyclopropane by Intramolecular C(sp)-H Activation at a Cyclic(alkyl)(amino)carbene Center and Its Fascinating Ring-Opening Chemistry.

Virtually irreversible intramolecular C-H activations are deleterious for aza-carbenes. A picolyl-tethered cyclic(alkyl)(amino)carbene (CAAC) isomerizes into a donor-acceptor cyclopropane in this manner but restores the CAAC status by retro-C-H activation in the presence of trapping agents like Se or CuCl. The same DA cyclopropane is readily hydrolyzed to a pyrrolidin-2-ol that acts as another CAAC precursor by undergoing 1,1-dehydration in the presence of Se or CuCl.

Mechanochemical solid state single electron transfer from reduced organic hydrocarbon for catalytic aryl-halide bond activation.

Solid-state radical generation is an attractive but underutilized methodology in the catalytic strong bond activation process, such as the aryl-halide bond. Traditionally, such a process of strong bond activation relied upon the use of transition metal complexes or strongly reducing photocatalysts in organic solvents. The generation of the aryl radical from aryl halides in the absence of transition-metal or external stimuli, such as light or cathodic current, remains an elusive process.

Deciphering the nitrate sources and processes in the Ganga river using dual isotopes of nitrate and Bayesian mixing model.

The dual isotopes of dissolved NO- (n = 43) has been used to delineate the nitrate sources and N-cycling processes in the Ganga river. The proportional contribution of nitrate from different sources has been estimated using the Bayesian mixing model. The seasonal NO- concentration in the lower stretch of the river Ganga varied between 4.

Intermolecular dearomative [4 + 2] cycloaddition of naphthalenes visible-light energy-transfer-catalysis.

The dearomative cycloaddition reaction serves as a blueprint for creating sp-rich three-dimensional molecular topology from flat-aromatic compounds. However, severe reactivity and selectivity issues make this process arduous. Herein, we describe visible-light energy-transfer catalysis for the intermolecular dearomative [4 + 2] cycloaddition reaction of feedstock naphthalene molecules with vinyl benzenes.

Assessing the Effect of Dopants on the C-H Activation Activity of γ-Al O using First-Principles Calculations.

In recent years, the high availability of methane in the shale gas reserves has raised significant interest in its conversion to high-value chemicals but this process is still not commercially viable. Metal oxides, due to their surface heterogeneity and the presence of Lewis acidic and basic site pairs are known to facilitate the activation of C-H bonds of methane. In this work, we investigate the C-H bond activation of methane on pristine and doped γ-Al O clusters using density functional theory (DFT) calculations.

Total syntheses of naturally occurring antiviral indolosesquiterpene alkaloids, xiamycins C-F Csp-H functionalization.

Concise total syntheses of naturally occurring antiviral indolosesquiterpene alkaloids, xiamycin C (2a), D (2b), E (2c) and F (2d), have been achieved a late-stage oxidative δ-Csp-H functionalization of an advanced pentacyclic enone intermediate 8. This strategy takes advantage of -nitration of naturally occurring abietane diterpenoids to synthesize -bromo nitroarene derivative 11. A Suzuki-Miyaura coupling of 11 with phenylboronic acid followed by Cadogan's ring closure provided a modular approach to a carbazole ring required for a functionalized pentacyclic core of indolosesquiterpene alkaloids.

Hemilabile Amine-Functionalized Efficient Azo-Aromatic Cu-Catalysts Inspired by Galactose Oxidase: Impact of Amine Sidearm on Catalytic Aerobic Oxidation of Alcohols.

A series of azo-aromatic copper(II) complexes, [] and a Cu(I) complex, [], with varying amine-functionalized hemilabile pincer-like [] and [], methyl-substituted azo [], and imine [] ligands, were synthesized and characterized. These complexes were investigated for aerobic oxidation of a variety of aromatic alcohols in the presence of 2.0 mol % precatalysts [], cobaltocene (2.