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isolation and structure of one new sesquiterpenoid (Ia) and two new sesquiterpene glycosides together with three known sesquiterpenoids

The first catalytic asymmetric aminotrifluoromethylation of alkenes by using Togni′s reagent (II) has been developed.

A facile and simple ligand-free copper-catalyzed reaction to synthesize substituted phenols is reported. The reaction presumably proceeds via an O-arylsulfonate intermediate that is hydrolyzed to afford good to excellent yields of up to 88%. This protocol provides an alternative to existing reports which use strong hydroxide salts as the direct hydroxylation partner. Demonstrating a wide substrate scope and functional group tolerance, this protocol can also be applied to inexpensive and commercially available carboxylic acids to yield phenols.

We report herein copper(II)-catalyzed cyclization reactions of silyl enol ethers derived from methyl ketones with α-diazo-β-ketoesters or α-diazoketones to afford 2-siloxy-2,3-dihydrofuran derivatives or 2,3,5-trisubstituted furans, respectively, under mild conditions. The former cyclization products serve as versatile 1,4-diketone surrogates, allowing facile preparation of 2,3,5-trisubstituted furans, pyrroles, and thiophenes.

The short review discusses a family of amorphous porous organic polymers, conjugated microporous polymer (CMP), which is distinctive in fusion of a large π-electronic conjugation within the topological network platform. The kind of polymers has shown the synthetic variety, the advanced capability and the wide applicability in contrast to the reported analogues. Herein, the significant progress of CMP applications has been summarized to showcase their capability in constructing photo-functional systems.

Li 4 MgOsO 6 was synthesized by two different solid-state reaction procedures. The crystal structures were determined by X-ray powder diffraction technique and it was revealed that Li 4 MgOsO 6 crystallizes in two different crystal symmetries in ordered rock salt structure type, namely monoclinic C2/m and orthorhombic Fddd . The unit cell constants for the monoclinic system are a =5.1074(4) A, b= 8.8182(4) A, c= 5.0902(2) A, and β =109.845 ( 4)° and those of the orthorhombic structure are a =5.8485(1) A, b =8.3821(1) A, and c =17.6212(3) A. In both systems, Os 6+ ions reside exclusively in a specific crystallographic position while Li + and Mg 2+ ions exhibit mix occupancy. The temperature dependent magnetic susceptibility data for both S=1 osmate systems do not support the occurrence of any magnetic transition down to 2 K. The Curie–Weiss fit to the paramagnetic regime of the magnetic susceptibility data reveal highly negative θ value (−114.81 K and −121.87 K for C2/m and for Fddd systems , respectively ) , which are indicative of predominant antiferromagnetic (AFM) interactions in both systems. The experimental effective magnetic moment ( μ eff ) value for the monoclinic phase is 2.13 μB and that of the orthorhombic system is 2.34 μB . Due to the rather strong AFM interactions and lack of magnetic transition down to 2 K, both of these novel osmates are placed in the class of highly frustrated magnets. Low temperature magnetic susceptibility (below 2 K) and dynamic magnetic properties studies (μsr studies) are in order to better understand the magnetic ground states of these two polymorphs of Li 4 MgOsO 6 .

A metal-free oxidative cross-dehydrogenative coupling of N-aryl tetrahydroisoquinolines and 2-methylazaarenes in water under mild conditions has been developed. 4-Acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate was employed as a mild oxidant that can be recovered and reused directly. The reaction proceeds through formation of an iminium ion in situ followed by condensation with various nucleophiles, providing the desired products in moderate to good yields.

New bipyridinemethanamine-containing tetradentate ligands and their corresponding ruthenium complexes have been synthesized. The synthesized complexes performed well in the hydrogenation of a variety of esters with high efficiency (TON up to 9700) giving alcohols in good yields.

A novel iridium/acid co-catalysed transfer hydrogenative coupling strategy, enabling direct alkylation of C(sp3)–H bonds and atom-economic access to alkyl chain-lengthened N-heteroaromatics from six-membered 2-alkyl cyclic amines and aldehydes, has been demonstrated. This work has built an important basis to convert cyclic amines, a class of bulk chemical raw materials, into functionalized products.

Air-stable and tunable chiral bisdihydrobenzooxaphosphole ligands (BIBOPs) were employed in rhodium-catalyzed asymmetric hydroformylation of various terminal olefins with excellent conversions (>99%), moderate-to-excellent enantioselectivities (up to 95:5 er), and branched to linear ratios (b:l) of up to 400.

Two novel meroterpenoids, rhodomentones A and B bearing an unprecedented caryophyllene-conjugated oxa-spiro[5.8] tetradecadiene skeleton, were isolated from the leaves of Rhodomyrtus tomentosa. Their structures with unique NMR characteristics were determined by extensive spectroscopic analysis, single-crystal X-ray diffraction, quantum molecular calculation, chemical transformation as well as total synthesis.

Herein, the sequential functionalization of 5-membered ring heterocycles is disclosed. By employing a pH sensitive directing group both directed and nondirected C–H activation pathways are available, providing access to 2,3,4- and 2,4,5-substituted thiophenes. The C–H arylation was performed in water, and using a surfactant greatly improved the yield and mass recovery. The use of a directing group with an on/off switch offers a potentially powerful means of generating diversity around medicinally relevant cores.

Highly active poly(hydroxamic acid) functionalized copper catalysts were synthesized by the surface modification of khaya cellulose through graft copolymerization and subsequent hydroximation processes. The prepared catalysts were well characterized by FTIR, FESEM, HRTEM, ICP-AES, UV-vis and XPS analyses. The supported catalysts effectively promoted C–N bond formation reactions and provided excellent yields of the corresponding products under mild reaction conditions. The catalysts were easy to recover from the reaction mixture and were reused several times without any significant loss of their catalytic activity.

Elucidation of absolute configuration of chiral molecules including structurally complex natural products remains a challenging problem in organic chemistry. A reliable method for assigning the absolute stereostructure is to combine the experimental circular dichroism (CD) techniques such as electronic and vibrational CD (ECD and VCD), with quantum mechanics (QM) ECD and VCD calculations. The traditional QM methods as well as their continuing developments make them more applicable with accuracy. Taking some chiral natural products with diverse conformations as examples, this review describes the basic concepts and new developments of QM approaches for ECD and VCD calculations in solution and solid states.

A novel and convergent approach to tetrasubstituted benzofurans was developed from ortho-bromo aryl fluorides and keto-amides via one-pot SNAr displacement and subsequent Cu(I) catalyzed C–O coupling on the ortho-bromide. The scope of this methodology was demonstrated on several similar substrates.

Without using any additional ligands, RuCl3 efficiently catalyses the reductive N-alkylation of aryl nitro compounds with alcohols using bio-based glycerol as the hydrogen source and without the need for any added solvents. The reaction can be easily manipulated to produce either imines or secondary amines in high yields. RuCl3-catalyzed reductive N-alkylation of nitroarenes with alcohols affords the corresponding imine products in good to excellent yields. Under the same reaction conditions, the one-pot sequential reaction of nitroarenes with alcohols and glycerol also gives amines in higher yields.

A series of tridentate ferrocene aminophosphoxazoline ligands like APX is synthesized and successfully applied to the asymmetric hydrogenation of ketones.

A new, metal-free oxidative 1,2-arylmethylation cascades of N-(arylsulfonyl)acrylamides for the assembly of 2,2-disubstituted-N-arylbutanamides containing an all-carbon quaternary center is presented. This reaction enables the one-step formation of two new C–C bonds through a sequence of methylation/1,4-aryl migration/desulfonylation using an organic peroxide as the methyl resource with a broad substrate scope and excellent functional group tolerance.

The synthesis of privileged structures, which are potent drug candidates, is an impetus for drug discovery. The construction of heterocyclic framework furo[3,2-c]coumarins using a visible-light promoted photoredox neutral coupling of 3-bromo-4-hydroxycoumarins with commercially available alkynes has been reported. These reactions can be carried out at room temperature under visible light irradiation with good chemical yields. This work presents 17 furocoumarins, 12 of which are new. Three of the newly synthesized compounds show potent cytotoxicity, and one shows moderate acetylcholinesterase inhibitory activity with IC50 values of 2.16 ± 0.13 μM.

Dye as a colored organic pollution has caused tremendous environmental problems. Removing dyes from effluents is of significant importance. Layered double hydroxides (LDHs), known as hydrotalcite-like compounds or ionic lamellar compounds, have attracted considerable attention recently due to the presence of large interlayer spaces, positively charged layers and solvation molecules. LDH-based materials are frequently used for environmental remediation especially for the elimination of dye compounds. This review compiles an extensive list of LDH-based low-cost sorbents and photocatalytic catalysts for dyes from the vast literature. Furthermore, performance, key factors and mechanisms involved in the processes are also included. Lastly, some major challenges together with prospects in this research field are discussed and highlighted. In conclusion, the application of LDH-based materials in the area of adsorption and catalysis science represents a useful and viable method, resulting in the outstanding capabilities in the removal of dyes from aqueous systems.

A new cobalt-based heterogeneous catalyst was prepared by adsorbing in situ produced nitrogen-ligated cobalt(II) acetate complexes on commercially available SiO2 and subsequent pyrolysis at 800 °C for 2 h under N2 atmosphere. By applying this catalyst under the O2 balloon, the aerobic oxidation of phenolic imines proceeded smoothly and gave various 2-arylbenzoxazoles in good yields. Meanwhile, on the basis of the experimental results, a plausible reaction pathway was described to elucidate the reaction mechanism.

A new benzylation protocol, enabling straightforward access to β-benzylated quinolines, has been demonstrated. By employing readily available [RuCl2(p-cymene)]2 as a catalyst and O2 as a sole green oxidant, various 1,2,3,4-tetrahydroquinolines were efficiently converted in combination with aryl aldehydes into desired products in a step- and atom-economic fashion together with the advantages of excellent functional group tolerance and chemoselectivity, offering an important basis for the transformation of saturated N-heterocycles into functionalized N-heteroaromatics via a dehydrogenative cross-coupling strategy. Mechanistic investigations support that the reaction undergoes a monodehydrogenation-triggered β-benzylation mode.

A highly mono-selective ortho-trifluoromethylation of benzamides was achieved via Cu-promoted C–H activations. The reaction employs an 8-aminoquinoline group as the bidentate directing group and Togni reagent II as the CF3 source. The reaction tolerated a wide variety of functional groups and various ortho-trifluoromethylated benzamides were efficiently synthesized in 36–82% yield.

Tomentodiones A (1) and B (2), a pair of C-11′ epimers of caryophyllene-conjugated phloroglucinols with an unprecedented skeleton, were isolated from the leaves of Rhodomyrtus tomentosa. Their structures were elucidated through the application of extensive spectroscopic measurements with the absolute configuration of 1 determined by single-crystal X-ray diffraction analysis and electronic circular dichroism (ECD) calculations. The biogenetic pathways of 1 and 2 were proposed to involve an intermolecular, inverse electron demand Diels–Alder cycloaddition reaction as the key step, and their biomimetic total synthesis was accomplished.

The development of renewable energy storage and conversion devices is one of the most promising ways to address the current energy crisis, along with the global environmental concern. The exploration of suitable active materials is the key factor for the construction of highly efficient, highly stable, low-cost and environmentally friendly energy storage and conversion devices. The ability to prepare two-dimensional (2D) metal dichalcogenide (MDC) nanosheets and their functional composites in high yield and large scale via various solution-based methods in recent years has inspired great research interests in their utilization for renewable energy storage and conversion applications. Here, we will summarize the recent advances of solution-processed 2D MDCs and their hybrid nanomaterials for energy storage and conversion applications, including rechargeable batteries, supercapacitors, electrocatalytic hydrogen generation and solar cells. Moreover, based on the current progress, we will also give some personal insights on the existing challenges and future research directions in this promising field.

A nickel-catalyzed intermolecular condensation of β-ketobutylanilides to synthesize multi-substituted pyri-din-2(3H)-ones was described. To the best of our knowledge, there is no report on the synthesis of these compounds. All the tested substrates with various functional groups irrespective of their nature, whether electron-donating or –withdrawing, and the location of the substituents on the aromatic rings, were all tolerated under the standard conditions and smoothly transformed into the desired products with 71 %-86 % yields. This strategy provides an efficient approach to valuable pyridin-2(3H)-ones via a sequential dehydration processes which may find applications in natural products and medicinal chemistry.

Four different types of TEMPO derivatives incorporated with an ionic liquid moiety and N,N-bidentate coordination group (IL–TEMPO-N,N) were prepared. The CuBr/IL–TEMPO-N,N system showed high catalytic activity toward the synthesis of aldehydes and imines via the aerobic oxidation of alcohols in 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4). Both the Cu catalyst and IL–TEMPO-N,N co-catalyst in homogeneous catalytic systems could simultaneously be recovered from the products by extraction using Et2O. The remaining catalyst system in the ionic liquid phase could be reused for several cycles without obvious loss of catalytic activity. Protocols for highly efficient and recyclable aerobic oxidation of alcohols to aldehydes and imines were established.

As one member of the emerging class of ultrathin two-dimensional (2D) transition-metal dichalcogenide (TMD) nanomaterials, the ultra-thin MoS2 nanosheet has attracted increasing research interest as a result of its unique structure and fascinating properties. Solution-phase methods are promising for the scalable production, functionalization, hybridization of MoS2 nanosheets, thus enabling the widespread exploration of MoS2 -based nanomaterials for various promising applications. In this Review, an overview of the recent progress of solution-processed MoS2 nanosheets is presented, with the emphasis on their synthetic strategies, functionalization, hybridization, properties, and applications. Finally, the challenges and opportunities in this research area will be proposed.

The first enantioselective tungstate-catalyzed oxidation reaction is presented. High enantioselectivities were achieved for a variety of drug-like phenyl and heterocyclic sulfides under mild conditions with H2 O2 , a cheap and environmentally friendly oxidant. Synthetic utility was demonstrated through the preparation of (S)-Lansoprazole, a commercial proton-pump inhibitor. The active ion-pair catalyst was identified to be bisguanidinium diphosphatobisperoxotungstate using Raman spectroscopy and computational studies.

A new layered manganese(II) phosphite, |NH4|4[Mn4(PO3H)6] (JIS-10), has been synthesised via the ionothermal method by using 1-pentyl-3-methylimidazolium bromide ([Pmim]Br) as the solvent. JIS-10 is the first manganese phosphite with a Mn/P ratio of 2/3, whose layered framework is built by the alternate connection of Mn2O9 dimers and PO3H pseudo-tetrahedra. JIS-10 represents an antiferromagnetic dimer system with S = 5/2 for each Mn2+ ion.

A novel HOTf-catalyzed oxyarylation of ynol ethers and thioethers has been realized with aryl sulfoxides as the oxyarylating reagents, providing α-arylated esters or thioesters in good to excellent yields. Notably, all atoms of the starting materials were incorporated in the product (100% atom economy) and the reaction proceeded under very mild conditions. It was found that the reaction can be ran under air and that the best yields are obtained under solvent-free conditions.

Selective functionalization of C(sp3)H bonds is one of the final frontiers of synthetic chemistry. The employment of organic dyes (ODs) as visible light photocatalysts to approach these reactions has been of current interest mainly due to their lower cost and the avoidance of toxic heavy metals. In this digest, we outline the recent advances in organic dye-catalyzed C(sp3)H functionalization reactions.

Asprellols A–C (1–3, resp.), three new 24-nortriterpenoids, were isolated from the CHCl3-soluble fraction of 95% EtOH extract of the roots of Ilex asprella, together with a known nortriterpenoid. The structures of the new compounds were elucidated as 2,6β,20β-trihydroxy-3-oxo-11α,12α-epoxy-24-norursa-1,4-dien-28,13β-olide (1), 2,6β-dihydroxy-3-oxo-11α,12α-epoxy-24-norursa-1,4,20(30)-trien-28,13β-olide (2), and 2,6β-dihydroxy-3-oxo-11α,12α-epoxy-24-noroleana-1,4-dien-28,13β-olide (3) on the basis of spectroscopic analyses.

Catalytic amounts of calcium and hydrogen triflimides [Ca(NTf2)2, HNTf2] were found to be efficient for the solvent-free formylation of a variety of weakly basic anilines by using cheap and widely available methyl formate as the formylating agent under microwave irradiation. Initial investigations showed that in the case of calcium triflimide, Bronsted acid catalysis was most likely operating. Remarkably, the corresponding calcium triflate and triflic acid were significantly less active.

This Letter describes the synthesis of olefins by coupling of electron deficient sulfonylhydrazones with aryl sulfinate salts in the presence of a palladium(II) catalyst under aerobic conditions. This methodology obviates the need for preparation of an organometallic and separate activation of the ketone starting material via a vinyl halide or triflate. The oxidant, reagent stoichiometry, and the electronics of the sulfinate coupling partner are reported.

Polypharmacology, the process in which a single drug is able to bind to multiple targets specifically and simultaneously, is an emerging paradigm in drug development. The potency of a given drug can be increased through the engagement of multiple targets involved in a certain disease. Polypharmacology may also help identify novel applications of existing drugs through drug repositioning. However, many problems and challenges remain in this field. Rather than covering all aspects of polypharmacology, this Minireview is focused primarily on recently reported techniques, from bioinformatics technologies to cheminformatics approaches as well as text-mining-based methods, all of which have made significant contributions to the research of polypharmacology.

A visible-light-induced and copper-promoted perfluoroalkylation of benzamides was successfully developed under the assistance of an 8-aminoquinoline directing group. It provides a straightforward method for the synthesis of ortho-perfluoroalkyl-substituted benzoic acid derivatives. The reaction employs a cheap organic dye eosin Y as the photoredox catalyst and is run under the irradiation of a 26 W fluorescent LED light bulb.

Polycrystalline Bi7Ta3O18 is prepared by firing a stoichiometric mixture of Bi2O3 and Ta2O5 (Pt boat, 950 °C, 18 h).

A series of electronically diverse imines were found to readily react with various donor–acceptor cyclopropyl acid chlorides, with complete regioselectivity, to form 1,3-oxazin-4-ones in moderate yields (25–48% over two steps). Select oxazinones underwent a base induced rearrangement to afford the corresponding cycloheptene-fused oxazinones in good yields (up to 70%).

This overview highlights the emergent area of mechanochemical reactions for making active pharmaceutical ingredients (APIs), and covers the latest advances in the recently established area of mechanochemical screening and synthesis of pharmaceutical solid forms, specifically polymorphs, cocrystals, salts and salt cocrystals. We also provide an overview of the most recent developments in pharmaceutical uses of mechanochemistry, including real-time reaction monitoring, techniques for polymorph control and approaches for continuous manufacture using twin screw extrusion, and more. Most importantly, we show how the overlap of previously unrelated areas of mechanochemical screening for API solid forms, organic synthesis by milling, and mechanochemical screening for molecular recognition, enables the emergence of a new research discipline in which different aspects of pharmaceutical and medicinal chemistry are addressed through mechanochemistry rather than through conventional solution-based routes. The emergence of such medicinal mechanochemistry is likely to have a strong impact on future pharmaceutical and medicinal chemistry, as it offers not only access to materials and reactivity that are sometimes difficult or even impossible to access from solution, but can also provide a general answer to the demands of the pharmaceutical industry for cleaner, safer and efficient synthetic solutions.

An efficient hydrogenation of aryl and alkyl aldehydes is examined, and the protocol is applied to the reduction of glucose.

2-Piperidinones are synthesized in a single step from imines and 2-cyano glutaric anhydrides. The reaction provides the products in good diastereoselectivity and generates a quaternary stereogenic center. Substitutions on the anhydride skeleton are well tolerated to provide 2-piperidinones with three stereogenic centers from a single transformation. The pertinent transition structures have also been computed using quantum mechanics and reveal the key interactions controlling the stereochemical outcome of the reaction.

Tomentosenol A (1), along with a pair of epimers, 4S-focifolidione (2) and 4R-focifolidione (3), were isolated from the leaves of Rhodomyrtus tomentosa. 1 was the first example of a new meroterpenoid class with a unique skeleton that contained a free syncarpic acid coupled with a terpenoid unit, and showed excellent antimicrobial and cytotoxic activities. The absolute configuration of 1 was unambiguously determined by a chemical conversion between 1 and the predetermined 2. In contrast to the common hetero Diels–Alder cycloaddition embodied in previously reported meroterpenoid biosynthesis, an Alder-ene reaction was proposed as the key transformation to account for the biosynthesis of 1, which was confirmed by a biomimetic total synthesis.