Letters in Organic Chemistry - Volume 10, Issue 8, 2013

An efficient halogenation reaction has been developed with diaryliodonium salts and cuprous halides. Various diaryliodonium salts 1 could perform the reaction with readily available CuBr or CuCl in CH3CN at 80°C, assembling bromoarenes or chloroarenes in up to 92% yields. This provides us a method for the transformation from iodoarenes to other haloarenes.

The synthesis of Azo-3-cyano-iminocoumarins and corresponding N-substituted derivatives is described according to three steps. These dyes which have not previously been described were obtained in good yields and high selectivity. The proposed structures of the dyes were confirmed and characterized by using IR, 1H NMR, 13C NMR and elemental analysis. Their optical properties, studied in chloroform by UV-vis absorption were found to depend strongly upon the nature of the substituent bone by the imino group and the azoic moiety.

A simple and efficient indium(III)-catalyzed sp3-sp C-C bond formation reaction via direct coupling of alcohols with terminal alkynes has been developed under mild conditions without any ligand, base or additive, in which both of aromatic and aliphatic alkynes and various alcohols such as benzylic, allylic and propargylic alcohols can be tolerated. This simple reaction system provides an attractive approach to a large number of internal alkynes in moderate to good yields, and only generates H2O as the side product.

A facile and efficient one-pot preparation of a new series of 1,4-dihydropyridines has been reported via a threecomponent reaction of nano aluminum nitride, aromatic aldehydes and benzyl-3-oxobutanoate or 2-methoxyethyl-3- oxobutanoateat 80 °C in water. Using this methodology, Hantzsch1,4-dihydropyridine derivatives were synthesized in a simple pathway without the use of a catalyst or an organic solvent.

The first entry to the 7,9,12b-triazabenzo[a]aceanthrylene ring system has been accomplished starting from readily accessible 1-(2-bromoacetyl)-β-carboline via 5-aminocanthin-4-one in four steps. The 8-oxo derivative, which can be considered as an annulated diazaacridone, exhibits significant antimicrobial properties.

A simple and practical procedure for the synthesis of 2-arylbenzimidazoles through a one-pot condensation reaction of o-phenylenediamine and various aromatic aldehydes in the presence of nano-Copper Y Zeolite (NCZ) as a catalyst in ethanol at room temperature has been described. The CuY Zeolite nanocatalyst was characterized with SEM image. Some of the major advantages of this practical procedure are use of available safe and reusable catalyst, high yields, short reaction time and easy and quick isolation of the product.

Synthesis of chiral acetals of phenol and bromophenol was carried out using (–) menthol as a pure chiral auxiliary. Metalation of these chiral acetals, followed by nucleophilic attack on different aromatic and aliphatic aldehydes produced chiral products through directed ortho metalation (DoM). Chiral menthoxymethyl (OMen) is developed as a new oxygen based chiral directed metalation group (DMG) for benzene and substituted benzene.

Ten known compounds were isolated from the leaves and barks of Walsura chrysogyne. One of the known compounds which was isolated as crystal was structurally confirmed by X-ray crystallography and named chrysura (5). The stereochemistry of the (20R, 24ξ)-ocotillone (9) which previously established by chemical methods has been elucidated by interpretation using 1D, 2D NMR and comparison with closely related compounds. Among the isolated compounds, eichlerianic acid (4) and viridiflorol (7) showed the most significant ichthyotoxicity against zebrafish (Danio rerio) with Median Tolerance Limit (TLM) of 6.7 and 15 ppm respectively.

Aniliniumcalix[4]arene dimers with peptide bridges to increase hydrogen bonding between amino acids and nucleic acid bases have been synthesized. Three different kinds of peptide bridges containing L-Alanine, L-Phenylalanine, and L-Tyrosine were prepared by liquid phase peptide synthesis. The dimers were characterized by NMR, MS and ESIMS spectrometry.

The development of dual-targeting drug delivery system is helpful to overcome the poor physiochemical properties of chemotherapeutic agents. The RGD sequence has a potential dual-targeting property, with which the chemotherapeutic agents can be delivered to bone tissue and tumor. And the Janus dendrimer which consists of two dendrons with different tasks is useful for improving the effect of polymer on pharmacokinetic properties. In this paper, a Janustype peptide dendrimer which consisted of RGD dimer and 5-FU dimer was synthesized and well characterized by 1H NMR and MS techniques, as well as the other three compounds for contrast. The hydroxyapatite binding assay and drug release study were evaluated. The Janus-type dendrimer with both enhanced targeting property and optimized release property, may reduce the side effects in normal tissues and have potential sustained-release effect. Thus, it may represent a novel opportunity to apply the versatile Janus-type dual-targeting delivery system to applications in bone tumor treatment.

The 1H–pyrazole-3-carboxylic acid 2 and its remarkably stable acid chlorides 3 can easily be converted into the corresponding carbohydrazide, ester or amide derivatives 4, 6 and 7, respectively, from reaction with alcohols or Nnucleophiles. The acid chloride (3) was also converted easily into the new derivatives consisting of 5-phenyl-1H-pyrazole 8a,b. The cyclocondensation reactions of 2 with some hydrazines led to the formation of pyrazolo[3,4-d ]pyradizinone 5 derivative. The nitrile derivative 9 was obtained by dehydration of 7a,b in a mixture of SOCl2 and DMF. The thermal decomposition of 4-Benzoyl-1-(4-nitrophenyl)-5-phenyl-1H-pyrazole-3-carboxylic acid 2b leads to the formation of [1-(4- nitrophenyl)-5-phenyl-1H-pyrazole-4-yl] phenylmethanone 10) It has been demonstrated that with the variation in reaction conditions, the reaction changes and leads to different products. The structures of these newly synthesized compounds were determined from the FT-IR, 1H and 13C NMR spectroscopic data and elemental analyses.

The accurate determination of ethanol is important in food technology, forensic laboratories, as well as in clinical analysis. Methods of ethanol assessment include spectrometry, gas chromatography, high performance liquid chromatography, but also biosensors, mainly with electrochemical or optical detection. The purpose of this study is the investigation of the role and influence of alcohol dehydrogenase and horseradish peroxidase amounts on the analytical characteristics of a bienzyme amperometric sensor for ethanol. The reduced form of the coenzyme, NADH, resulted in the alcohol dehydrogenase-catalysed reaction, is oxidized by molecular oxygen, under the influence of horseradish peroxidase. Both enzymes were coimmobilized with NAD+ on a nylon membrane, fixed on an oxygen electrode. The oxygen consumption, proportional to the NADH amount, can be correlated to the ethanol concentration. The analytical performances of the biosensor were studied at alcohol dehydrogenase loadings ranging between 100 and 900 units and horseradish peroxidase loadings ranging between 0 and 30 units. The improvement of the bienzyme sensor allowed ethanol assessment in wine and beer.