2437-05-0

Abstract: Several highly efficient and magnetically recyclable cobalt catalytic systems were prepared using magnetic chitosan and some safe and available organic compounds (Co-ligand@MNPs/Ch). The structure of these nanocomposites was confirmed by various physicochemical techniques such as FT-IR, XRD, TGA, VSM, TEM, SEM, CHNS and ICP-OES. These nano composites exhibit remarkable catalytic efficiency for Suzuki and Heck cross-coupling reactions in mild and green reaction conditions. The facile accessibility of starting materials, possible performance in air and eco-friendly conditions are merits of our catalysts. In addition, to describe and go insight to role and effect of ligands present in these catalysts, electrostatic interactions, density functional theory (DFT) model in molecular method were employed. Graphic Abstract: [Figure not available: see fulltext.]

β-Substituted acrylamides have low electrophilicity and are yet to be exploited in the enantioselective Rauhut–Currier reaction. By exploiting electron-withdrawing protection of the amide and moderate nucleophilicity N-heterocyclic carbenes, such substrates have been converted to enantioenriched quinolones. The reaction proceeds with complete diastereoselectivity, good yield, and modest enantioselectivity. Derivatizations are reported, as are computational studies, supporting decreased amide bond character with electron-withdrawing protection of the nitrogen.

We report an easy process to synthesize sulphonic acid functionalized porphyrin, anchored with a meso-substituted triazolium ionic liquid moiety (SAFPTILM) for metal/base free C-C cross-coupling and C-N/C-H activation using aryl chloride under visible light irradiation. The acid strength has been measured based on the Hammett indicator. The SAFPTILM photocatalyst comprising 18 π-conjugated electronic systems with the chromophore substituents in the meso-position can provide rapid electronic conducting channels during photocatalysis under the irradiation of visible light. It was found that SAFPTILM is an efficient photocatalyst for the Heck, Sonogashira, Buchwald, Ullmann/Fittig coupling and C-H activation of phenols with different aryl chlorides in the absence of a base/noble metal, using 5 W LED (yellow) light under ambient conditions. The photocatalyst with low band gap (1.55 eV) comprising conjugation, favors coupling reaction of unactivated aryl chlorides, by easy excitation of electrons and transfer to the conjugated benzimidazolium based phenylenediamine support delaying the recombination of photoinduced electron-hole pairs.

A palladium-melamine complex deposited on Fe3O4@SiO2 nanoparticles (MNPs-Mel-Pd) was considered as an effective catalyst for C-C cross-coupling (Mirozoki-Heck) reaction. Surface and magnetic properties of the prepared core-shell hybrid nanocatalyst was characterized using Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, energy-dispersive X-ray, vibrating sample magnetometry, transmission and scanning electron microscopy techniques and ICP/OES analysis. It was found that the heterogeneous nanocatalyst could be recovered simply and reused numerous times without loss of its catalytic activity. The advantages of this new methodology are: isolation of highly pure products without chromatography techniques, reusability of the catalyst using a magnet, easy workup procedure and negligible leaching of palladium.

The invention discloses a synthetic method of an indoline-2-ketone compound and an application thereof. The synthetic method comprises the following steps: enabling a nitrobenzaldehyde compound, alkali and phosphorus ylide to react, and preparing a 2-nitr

The synthesis, characterization and in situ catalytic performance of new unsymmetric N,N′-disubstituted imidazolium-based dicationic salts in Mizoroki–Heck coupling of acrylates with aryl bromides under aerobic conditions are described. A series of flexible dicationic salts with varying steric and electronic properties were synthesized in good to excellent yields. All the salts were well characterized using spectroscopic techniques. X-ray diffraction analysis of two salts with the same dicationic backbone and different counter anions shows that the ligand adopts two different conformations which are influenced by the nature of the anion. Thus, the ligand is capable of changing its conformation according to the change in environment due to its flexible nature. All the synthesized imidazolium salts were found to be active in in situ palladium-catalysed Mizoroki–Heck coupling under aerobic conditions. Amongst the salts, the hydroxyl-functionalized imidazolium salt, incorporating the features of both bidentate chelating O,O ligand and carbene, shows the maximum catalytic activity. A variety of aryl and heteroaryl methyl and ethyl cinnamates were synthesized using these imidazolium salts as preligands. In addition, NMR studies confirm in situ generation of normal N-heterocyclic carbenes from the C-2 position of imidazol-2-ylidene ring. The mercury poisoning test was also performed to ascertain the nature of catalytically active palladium species. Aerobic conditions, low catalytic loading (0.5?mol%), shorter reaction times, broad functional group tolerance and good to excellent isolated yields are some of the significant features of the novel catalytic systems described here. Copyright

In the present work, S-substituted derivatives of 5-(2-nitrostyryl)-1,3,4- oxadiazole-2-thiol (4) were synthesized by successive conversions of 3-(2-nitrophenyl) acrylic acid (1) into its respective ester, hydrazide and 1,3,4-oxadiazole. Finally the targe

The first concise total syntheses of pyrroloquinoline natural products, Marinoquinolines A-C, have been achieved in six linear steps from commercially available starting materials. The key steps were a reaction between (p-tolylsulfonyl)methylisocyanide (TosMIC) and α, β-unsaturated ester under basic condition to prepare the pyrrole moiety and Morgen-Walls reaction to construct quinoline ring.

Carbene adduct of cyclopalladated ferrocenylimine has been successfully applied to Heck reaction of various aryl bromides with olefins. On the basis of kinetic studies, in situ 13C NMR spectra investigations and Hg poisoning experiments, it was proposed that the Heck reaction catalyzed by carbene adduct of cyclopalladated ferrocenylimine proceeded through a classical Pd(0)/Pd(II) cycle and such palladacycle was only a reservoir of the catalytically active Pd(0) species.

(Chemical Equation Presented) The Cadogan reaction, a widely accepted route for the synthesis of nitrogen containing heterocycles, is modified by using microwave radiation as the source of heat instead of the conventional heating by reflux in a nitrogen atmosphere for several hours. Appropriate starting materials were mixed with triethyl phosphite or triphenylphosphine and irradiated with microwaves for several minutes at a specific power to give the desired products. The indazoles were prepared by irradiating N-(2-nitrobenzylidene) anilines with triethyl phosphite at 200 W for 12-14 min to give 85-92% product yields. Irradiation of the mixture of N-benzylidene-2-nitroanilines and triphenylphosphine at 200 W for 3-5 min yielded 93-96% of the benzimidazoles. The carbonylindoles were obtained in 61-68% yields by irradiating 2-nitrochalcone or alkyl 2-nitrocinnamates and triphenylphosphine with microwaves at 80-200 W for 8-11 min. The mixture of 2-nitrobiphenyl and triphenylphosphine yielded 96% of carbazole when irradiated with microwaves at 200 W for 2 min while 75% of phenazine was obtained by irradiating the mixture of 2-nitrodiphenylamine and triphenylphosphine with microwaves at 200 W for 3.5 min. These results show that microwave-assisted Cadogan reactions gave better product yields at shorter reaction times.

There are provided novel 4-(2-furoyl)aminopiperidines represented by the general formula (I), their synthetic intermediates, processes for their preparation and medicaments containing them. In the above formula, X is CH or N, and Y is a group of the following general formula (II), formula (II-a) or formula (III): wherein a, b and c are each an integer of 0-6; Z is CH2 or NH; W is O or S; T is O or N-R15 wherein R15 is H, a C1-C6 alkyl group, a benzyl group or a phenethyl group; and R1 is H, a C1-C6 alkoxycarbonyl group, a benzyloxycarbonyl group, or the like.The 4-(2-furoyl) aminopiperidine derivatives according to this invention possess opioid μ antagonistic activity and are useful for the treatment or prevention of side effects which are caused by μ receptors agonist and which are selected from constipation, nausea/emesis or itch, or for the treatment or prevention of idiopathic constipation, postoperative ileus, paralytic ileus, irritable bowel syndrome or chronic pruritus.

Imidoyl radicals, generated from imidoyl phenylselanide precursors, have been used for the synthesis of 2,3-disubstituted indoles. A facile high yielding synthesis of imidoyl phenylselanides has been developed. The potential for neophyl rearrangement of 5

Treatment of 3-(2-aminophenyl)-2-propenyltriphenylphosphonium bromide with acid anhydride and tertiary amine affords 1,3-diacylindoles in yields ranging from 22 to 64%. A plausible mechanism of this new cyclization reaction is described.

A rapid method for the title synthesis of β-aryl-β-amino acid esters was developed, and the absolute configurations of newly formed C-3 chiral centres in the major and minor diastereomers of the resulting ethyl N-[(S)-α-methylbenzyl]-β-amino-β-phenyl-propionate were determined.

The rates of nitration of ethyl cinnamate, cinnamic acid, β-nitrostyrene, and trimethyl(styryl)ammonium ion in sulphuric acid of a range of concentrations have been determined.The nitrovinyl and the trimethyl(vinyl)-ammonium groups deactivate the aromatic nucleus by factors of ca. 330 and 60, respectively.The yields of products from ethyl cinnamate and β-nitrostyrene, nitrated over a range of sulphuric acid concentrations, are reported.With ethyl cinnamate the o:p ratio falls with increasing acidity.The acidity dependences of the rates of reaction of ethyl-4-nitrocinnamate, 4-nitrocinnamic acid, ethyl 3-nitrocinnamate, and 3-nitrocinnamic acid with nitric acid in sulphuric acid show the primary reaction in each case to be attack by the nitronium ion (at the β-carbon atom).The reactions are completed by addition, giving nitroalcohols.A similar but much slower reaction occurs with β,4-dinitrostyrene.In every case the nitroalcohol decomposes in concentrated sulphuric acid to give the nitrobenzaldehyde.With absolute nitric acid, ethyl 4-nitrocinnamate gives the side-chain nitro-nitrate by formal syn-addition.Addition of nitromethane to the reaction solution leads to addition in both stereochemical modes.The nitro-nitrate gives the nitro-alcohol in sulphuric acid, but in aqueous media gives ethyl α-nitro-β-(4-nitrophenyl)acrylates.These apparent side-chain nitrations are thus addition-elimination reactions, as suggested by van der Lee.Similar processes have been detected in the cases of 4-nitrocinnamic acid and β,4-dinitrostyrene.

?+ Substituent constants for the orto- and para-vinyl group have been determined by the application of the linear free-energy relationship to the nitration of the β-substituted styrene derivative.Energy changes (relative to benzene system) for the proton and hydride ion transfer to individual positions in the styrene molecule have been calculated.Both approaches indicate that the vinyl group is capable of stabilizing both positively and negatively charged transition states.The interactions of the vinyl group with other substituents in the phenyl ring are also determined.Again, stabilizing effects with respect to both ?-donor and ?-acceptor substituents have been demonstrated for the vinyl group.