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We propose an intramolecular synergistic counteracting strategy of fluorescence resonance energy transfer and the inner filter effect for accurate photoactivation monitoring, to eliminate the influence of the biological microenvironment.

Chemical transformation with vinylene carbonate as an emerging synthetic unit has recently attracted considerable attention. This report is a novel conversion pattern with vinylene carbonate, in which such a vibrant reagent unprecedentedly acts as a difunctional coupling partner to complete the C-H annulation of free anilines. From commercially available substrates, this protocol leads to the rapid construction of synthetically versatile 2-methylquinoline derivatives (43 examples) with excellent functionality tolerance.

Here we report a novel Rh-catalyzed C-H/C-H alkenylation of N-arylmethanimines with vinylene carbonate acting as a vinylene unit. Forty examples of C3,C4-nonsubstituted quinolines were achieved from commercially available starting materials. This identified process features an exceedingly simple system, a lower loading of catalyst, and the capacity for postfunctionalization with bioactive molecules.

We report palladium–BIAN–NHC chloro dimer complex, [Pd(BIAN–IPr)(μ-Cl)Cl]2. This rapidly activating catalyst merges the reactive properties of palladium chloro dimers, [Pd(NHC)(μ-Cl)Cl]2, with the attractive structural features of the BIAN framework.

We report a new copper-catalyzed [2 + 2 + 1] annulation process through the selective cleavage of sigma and triple C-C and C-H bonds using two ynone units. This new methodology involves breaking multiple chemical bonds in a single operation, including C≡C, C-C, C-H, and N-O. These high-value adducts lead to a diverse collection of synthetically challenging trisubstituted indolizines by the simultaneous engagement of different bond-breaking events and show excellent fluorescence in green aqueous solutions.

A rhodium(III)-catalyzed formal C–H [5 + 1] cyclization of 2-pyrrolyl/indolylanilines with vinylene carbonate has been explored towards the potent assembly of diverse 4-methylpyrrolo[1,2-a]quinoxalines. This established protocol is characterized by an exceedingly simple reaction system, and excellent functional group toleration and yields. Most importantly, entirely distinct from documented [4 + 2] cyclization conversions, herein, the emerging vinylene carbonate firstly presents as a C1 synthon to realize [5 + 1] annulation and shows new chemical reactivity. Biological studies indicate that these prepared products are promising candidates in terms of their antibacterial activity.

A zinc-catalyzed C–H alkenylation of quinoline N-oxides with ynones has been developed to rapidly assemble a broad collection of valuable quinoline-enol organic architectures. Uncommonly, this novel reaction involves C–H functionalization, and N–O, C–C and CC bond cleavage in one operation, and leads exclusively to the formation of an enol rather than a keto product. Application of the enols generated was highlighted by further derivative transformation and preparation of a series of “BODIPY” analogues with high quantum yields (up to 86%).

An acid-functionalized ionic liquid (IL)-catalyzed cascade decarboxylative cyclization of 2-arylanilines with α-oxocarboxylic acids was developed. This approach offered a sustainable and practical pathway to afford a library of quinoxalines in water under ambient conditions. This protocol tolerated various kinds of functional groups and could be easily scaled-up. The developed method featured a recyclable catalytic system, environmentally friendly reaction conditions, simple operation, and a practical workup procedure, which represented the potential to streamline quinoxaline synthesis in industry. A possible mechanism involving a dual activation strategy to promote both decarboxylation and cyclization processes was proposed.

Ruthenium(II)-catalyzed ortho-C-H alkylation of naphthylamines with diazo compounds for the synthesis of 2,2-disubstituted π-extended 3-oxindoles has been developed. The method represents the first example of C-H alkylation via carbenoid insertion in water as a sustainable solvent. The procedure includes an inexpensive ruthenium catalyst as well as aqueous media and results in the release of benign N2. The π-extended 3-oxindole products exhibit favorable antitumor properties and remarkable fluorescent properties in aqueous solution for fluorescent imaging.

Although cross-coupling reactions of amides by selective N-C cleavage are one of the most powerful and burgeoning areas in organic synthesis due to the ubiquity of amide bonds, the development of mechanochemical, solid-state methods remains a major challenge. Herein, we report the first mechanochemical strategy for highly chemoselective, solvent-free palladium-catalyzed cross-coupling of amides by N-C bond activation. The method is conducted in the absence of external heating, for short reaction time and shows excellent chemoselectivity for σ N-C bond activation. The reaction shows excellent functional group tolerance and can be applied to late-stage functionalization of complex APIs and sequential orthogonal cross-couplings exploiting double solventless solid-state methods. The results extend mechanochemical reaction environments to advance the chemical repertoire of N-C bond interconversions to solid-state environmentally friendly mechanochemical methods.

We report the synthesis of C6-substituted isoquinolino[1,2-b]quinazolinones via rhodium(III)-catalyzed C-H annulation with sulfoxonium ylides and evaluation of the cytotoxic activity of the scaffold. This C-H activation approach enables the most straightforward and convergent synthesis of C6-substituted isoquinolino[1,2-b]quinazolines reported to date. This operationally simple method is compatible with a wide variety of the sulfoxonium ylide and arene C-H activation coupling partners, permitting access to diverse isoquinolino[1,2-b]quinazolines. This method shows a high atom economy, generating H2O and dimethyl sulfoxide (DMSO) as by-products. This method is scalable and operates with exquisite N-lactam cyclization selectivity, thus enabling expedient access to new heterocyclic analogues featuring promising cytotoxic properties.

Rhodium(III)-catalyzed C–H amidation of 2-arylindoles with dioxazolones for the synthesis of indolo[1,2-c]quinazolines is reported. The reaction is compatible with a wide range of electronically diverse 2-arylindoles and dioxazolones, providing indolo[1,2-c]quinazolines in high to excellent yields. Most notably, the combination of this Rh-catalyzed C–H amidation and intramolecular N–H/N–C(O) cyclization enables the most straightforward direct route to indolo[1,2-c]quinazolines to date. Mechanistic studies and evaluation of antitumor activity of these high value heterocycles are disclosed.

A novel [5 + 1] cyclization of 2-vinylanilines with polyfluoroalkanoic acids under catalyst- and additive-free conditions was successfully implemented. The approach directly employs very low-cost and readily available polyfluoroalkanoic acids as both C1 synthons and fluoroalkyl building blocks. This method provides concise access to diverse 2-fluoroalkylated (CF3, C2F5, C3F7, CF2H, CF2Cl, and CF2Br) quinolines in good yields with excellent functional group tolerance in high yield on a gram scale.

We report ruthenium(II)-catalyzed ortho-C–H arylation of N,N-dialkylthiobenzamides with boronic acids. The method employs [RuCl2(p-cym)]2 in the presence of Cu(OTf)2 and Ag2O oxidant. The reaction ...

A catalyst-free method for the hydroxylation of arylboronic acids to form the corresponding phenols with sodium perborate as the oxidant was developed using water as the solvent. Under the reaction conditions, the yield of phenol reached 92% at only 5 min. Moreover, the reaction could be conducted without a catalyst under the solvent-free condition, the efficiency of which was as high as that of a liquid-phase reaction. Using a microcalorimeter, the reaction was found to be an exothermic reaction. The reaction mechanism was investigated and understood via DFT calculations, which revealed that it was a nucleophilic reaction.

We developed a general and sustainable approach for the regioselective deoxygenative chalcogenation of 7-azindole N-oxides; the combination of an internal oxidant and a green solvent has been used successfully for the synthesis of mono- and dichalcogenyl 7-azaindoles which are of pharmaceutical interest. The regioselectivity is tunable by the variation of the reaction conditions. I2/PEG was established as an efficient and reusable catalytic system for C–H chalcogenation. This developed methodology has great potential for practical utility, with a broad substrate scope, green reaction conditions, and operational simplicity.

A general Pd-catalyzed synthesis of amides by oxidative aminocarbonylation of arylsilanes under mild conditions was accomplished for the first time. The reaction is promoted by a commercially available copper(II) fluoride, which acts as a dual silane activator and mild oxidant, enabling highly efficient aminocarbonylation of versatile arylsilanes at atmospheric CO pressure. The reaction is tolerant of a wide range of arylsilanes and various sensitive halide functional groups as well as a broad scope of amines are compatible with this oxidative process using cheap CO. A significant aspect involves the increased efficiency by the catalyst system. The reaction represents a segue into the powerful Pd-catalyzed oxidative transformations of organosilanes.

V/UiO-66-NH2 was prepared by the vanadium oxyacetylacetonate grafted on UiO-66-NH2. The catalytic performance of V/UiO-66-NH2 was investigated for the hydroxylation of benzene to phenol using O2. It can give the high yield of 22.0% for phenol with high selectivity of 98.1% while the UiO-66-NH2 as the catalyst can give the yield of 5.2%. The synergetic effect between the Zr MOF and the V complex was contributed to the high efficiency of the V/UiO-66-NH2 catalyst. Furthermore, the V/ZrO2 catalyst obtained by calcination of V/UiO-66-NH2 under the nitrogen gave the yield of 16.2% with the selectivity of 98.3%, which can be recycled. The catalysts can also be employed for the co-reductant free catalyst, which give the yield of about 5% with high selectivity.

Vanadium-zirconium catalyst was prepared with zirconium tetrachloride and ammonium metavanadate, which were supported on different supports, such as activated carbon, g-C3N4, MWCNTs (multiwall carbon nano tubes), acidified MWCNTs, bentonite, and γ-Al2O3. Various techniques were employed to characterize the catalysts such as X-ray diffraction, X-ray photoelectron spectroscopy, nitrogen adsorption, and Raman spectrum. It was found that Zr4+ and V5+ in the vanadium-zirconium catalyst were dispersed on support in the form of zirconium pyrovanadate. The performance of catalysts on hydroxylation of benzene to phenol with O2 as the oxidant was investigated. The vanadium-zirconium catalyst with different supports showed different catalytic performance and the reason was studied. It was found that the catalytic performance was related to the nature of the supports including the surface area and the composition of the supports. The yield of phenol reached to 8.6% and selectivity reached to about 80% when the activated carbon acted as support. Kinetic study showed that the first step of the consecutive reaction was first order for benzene and the second step was first order for phenol.

We report the synthesis of C6-substituted isoquinolino[1,2

Quinone-amine polymers were employed as metal-free and reductant-free catalysts for the hydroxylation of benzene to phenol with molecular oxygen, yielding phenol as high as the transition metal catalyst.

Zanthoxylum bungeanum seed oil (ZSO) cannot be widely consumed because it contains high free fatty acids with an acid value of 73.75 mg KOH per g. Herein, a solid acid catalyst was prepared from ZSO via a carbonization–sulfonation method using concentrated sulfuric acid. The prepared catalyst was characterized by FT-IR, SEM, XPS, XRD, N2 physisorption, and Boehm titration methods. The prepared solid acid was employed as a catalyst to investigate its performance during the simultaneous esterification and transesterification of ZSO in a one-pot process to produce biodiesel. The optimum reaction parameters for obtaining biodiesel in >95% yield using the abovementioned reaction were as follows: 30 : 1 methanol-to-oil molar ratio, a catalyst loading of 8.0 wt%, a reaction temperature of 140 °C, and reaction time of 4.0 h.

A series of VxOy@C catalysts was prepared from different types of biomass and NH4VO3 using a hydrothermal method. The prepared catalysts were characterized using a series of methods including XRD, SEM, FT-IR, SEM and XPS to investigate the mechanism of formation of the VxOy@C catalysts. Furthermore, the factors related to the selectivity of phenol and the mechanism of the hydroxylation of benzene to phenol were studied. It was found that the activity was related to the V species on the catalyst and the selectivity was related to the adsorption of phenol.

An environmentally benign nano CuO catalyzed strategy has been developed for one-pot synthesis of quinazolinone Schiff base derivatives and bis-2,3-dihydroquinazolin-4(1 H )-ones by use of hydrazine hydrate and ethidene diamine as nitrogen source. The antibacterial activity was investigated using minimum inhibitory concentration (MIC) method against four bacterial strains. Tests have shown that these derivatives have potential activity against Streptococcus lactis . The structure–activity relationship of the antibacterial activity evaluation was also explored.

Two series of spiro-oxindole dihydroquinazolinone derivatives have been designed and synthesized using a catalytic amount of nano cerium oxide with excellent product yields by a convenient one-pot process. The synthesized compounds were evaluated for their in vitro antibacterial activity, and compounds 1i–1p showed considerable antibacterial activities to Escherichia coli. Molecular docking of E. coli Biotin Carboxylase (EcBC) enzyme was also performed in order to predict the interactions of the synthesized compounds.

Based on the spirotryprostatin A structure, a series of compounds belonging to spiro-indolyl diketopiperazine structural class were designed and synthesized, which embody an oxindole with an all-carbon quaternary stereocenter. The total synthesis can efficiently be accessed in a seven-step reaction sequence with 18-28% overall yield from commercially available materials, and a highly enantioselective 1,3-dipolar cycloaddition, N-acylation of the resulting stereochemically complex spiro[pyrrolidin-3,3'-oxindole]s core with Fmoc-L-pro-Cl and spontaneous ring closure upon N-deprotection were obtained. The synthesized compounds 13a-e and 15a-e were evaluated for their antibacterial activities. The result showed that compounds 13b and 15b were active only against Gram-positive bacteria, and selective antibacterial activity was exhibited by compounds 13d and 13e against Streptococcus lactis. Further, all the remaining compounds showed a certain degree of antibacterial activity. In addition, the structure-activity relationship is also discussed.

A CuO nanoparticle-catalyzed one-pot process has engineered for the preparation of diverse quinazolinones from the readily available isatoic anhydride, aldehydes and amine or ammonium. For amine substrates the reactions afford 2,3-dihydroquinazolin-4(1 H )-ones in aqueous ethanol promoted by ultrasound irradiation. However, the ammonium substrates undergo intramolecular electron transfer and rearrangement yielding quinazolin-4(3 H )-ones. The catalyst is recyclable four times without loss of substantial activity. Other remarkable features include the wide range of functional group tolerance (46 quinazolinones are synthesized and 9 of them are reported firstly), and providing moderate to excellent yield of the products under mild conditions.

A series of single isomers tetrahydro-β-carboline diketopiperazines were stereoselectively synthesized starting from l-tryptophan methyl ester hydrochloride and six aldehydes through a four-step reaction including Pictet-Spengler reaction, crystallization-induced asymmetric transformations (CIAT), Schotten-Baumann reaction, and intramolecular ester amidation. The chemical structures were characterized by nuclear magnetic resonance (NMR) and elemental analysis, among which two compounds were determined by x-ray single crystal diffraction. Moreover, antimicrobial activities of all the compounds were also tested.

Two series of spiro-oxindole dihydroquinazolinone derivatives have been designed and synthesized using a catalytic amount of nano cerium oxide with excellent product yields by a convenient one-pot process. The synthesized compounds were evaluated for their in vitro antibacterial activity, and compounds 1i–1p showed considerable antibacterial activities to Escherichia coli. Molecular docking of E. coli Biotin Carboxylase (EcBC) enzyme was also performed in order to predict the interactions of the synthesized compounds.

Two series of indolyldiketopiperazines were synthesized starting from methyl 1-substituted-1,2,3,4-tetrahydro-β-carboline-3-carboxylate hydrochlorides via N-bromo-succinimide (NBS) as an important reagent. All eight compounds were characterized by nuclear magnetic resonance (NMR) and elemental analysis. Furthermore, the mechanisms of NBS-reacted rearrangements are also discussed. Chirality 26:790–792, 2014. © 2014 Wiley Periodicals, Inc.

The catalyst can be recycled and reused at least 4 times without a significant loss in activity.