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It was found that oligo(hexamethylene guanidine) (OHMG) reacted very slowly with unactivated high-molecular-mass alkyl halides (dodecyl chloride), possibly due to steric hindrance and the low nucleophilicity of the guanidine moiety. Therefore, this alkyl halide could not be used to modify OHMG under conventional conditions. Ethylation of OHMG was much more facile. However, the substitution in the derivatives was broadly scattered (under ordinary conditions and reagent ratios). It was shown simultaneously that the antibacterial activity of the alkylated derivatives was less than that of the starting OHMG hydrochloride. Benzyl chloride reacted readily with OHMG to produce derivatives with the desired degree of substitution. It was found that benzyl derivatives with 0.2 degree of substitution were more active against mycobacteria than the starting hydrochloride with the activity gradually diminishing if the degree of substitution was increased further. The increased activity may have been related to the optimum increase of OHMG hydrophobicity and/or steric structure. The rather high antibacterial activities of the benzyl derivatives against Mycobacterium smegmatis strain ATCC 607 made them promising for further development and studies of the properties of alkylated OHMG derivatives to discover more active derivatives, including against M. smegmatis. The most obvious candidates could become the methylcarboxy-substituted OHMG derivatives. [ABSTRACT FROM AUTHOR]

S-Adenosylmethionine-dependent methyltransferases (MTs) play a decisive role in the biosynthesis of natural products and in epigenetic processes. MTs catalyze the methylation of heteroatoms and even of carbon atoms, which, in many cases, is a challenging reaction in conventional synthesis. However, C-MTs are often highly substrate-specific. Herein, we show that SgvM from Streptomyces griseoviridis features an extended substrate scope with respect to the nucleophile as well as the electrophile. Aside from its physiological substrate 4-methyl-2-oxovalerate, SgvM catalyzes the (di)methylation of pyruvate, 2-oxobutyrate, 2-oxovalerate, and phenylpyruvate at the β-carbon atom. Chiral-phase HPLC analysis revealed that the methylation of 2-oxovalerate occurs with R selectivity while the ethylation of 2-oxobutyrate with S-adenosylethionine results in the S enantiomer of 3-methyl-2-oxovalerate. Thus SgvM could be a valuable tool for asymmetric biocatalytic C-alkylation reactions. [ABSTRACT FROM AUTHOR]

An efficient Cu-catalyzed stereoselective trifluoroethylation through the decarboxylative cross-coupling of cinnamic acid derivatives with CF 3 CH 2 I is described. The ready availability of the starting materials, the high level of functional group tolerance, and excellent E selectivity make this protocol a safe and operationally convenient strategy for the efficient synthesis of trifluoroethyl derivatives. [ABSTRACT FROM AUTHOR]

Using alkyl 4,5-bis(diethoxyphosphorylmethyl)furan-3-carboxylate as examples, we have demonstrated the possibility of synthesis of a phosphorylated analog of aglycone of the glycoside regulator of cellulose and callose synthesis, bis(phosphorylated) furoyl derivatives of natural amino acids, and phosphorus-containing derivatives of N-furyl- N′-hydroxyethylurea; these compounds are of interest for pharmacology. [ABSTRACT FROM AUTHOR]

A novel route for the environmentallyfriendly synthesis of diethyltoluene diamine (DETDA) was developed by the ethylation of 2,4-toluenediamine (2,4-TDA) over acidic zeolites using ethene and ethanol asthe alkylation reagents. Different types of zeolites and reactionconditions were examined. Monoethyl toluene diamine (ETDA) was firstgenerated and then DETDA was formed by ethylation of ETDA. Triethyltoluene diamine (TETDA) was the excessive ethylation product. Theacidic zeolites were characterized by NH3temperature-programmeddesorption, pyridine adsorption Fourier transform infrared spectroscopy,argon/nitrogen physisorption and scanning/transmission electron microscopy.The acidity, especially the Brønsted acid sites on the externalsurface of zeolites, plays a more important role in the ethylationthan the pore channel does. A small crystal size exposing more acidsites on the external surface is beneficial for the producing of DETDA.The treatment with NaOH generating meso- and macropores and increasingexternal surface area can also improve the catalytic activity of ZSM-5. [ABSTRACT FROM AUTHOR]

The [ 18 F]fluoroethyl moiety has been widely utilized in the synthesis of 18 F-labelled compounds. The aim of this work was the reliable synthesis of [ 18 F]FEtOTf with a novel strategy to increase the reactivity of the commonly used [ 18 F]FEB and [ 18 F]FEtOTos. [ 18 F]FEtOTf and the intermediate [ 18 F]FEtOH were synthesized in high RCY (78% and 85%, respectively) and purified by SPE. The high potency of [ 18 F]FEtOTf was shown by the efficient alkylation of the deactivated nucleophile aniline under mild conditions, as well as by the synthesis of [ 18 F]FEC. [ABSTRACT FROM AUTHOR]

A practical strategy has been described for the preparation of 6-trifluoroethyl-phenanthridine derivatives using a visible-light-promoted trifluoroethylation reaction of 2-isocyanobiaryl with trifluoroethyl iodide. These reactions could be carried out at room temperature in good to excellent chemical yields with good functional group tolerance. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed selective CH bond trifluoroethylation of aryl iodides has been explored. The reaction allows for the efficient synthesis of a variety of ortho-trifluoroethyl-substituted styrenes. Preliminary mechanistic studies indicate that the reaction might involve a key PdIV intermediate, which is generated through the rate-determining oxidative addition of CF3CH2I to a palladacycle; the bulky nature of CF3CH2I influences the reactivity. Reductive elimination from the PdIV complex then leads to the formation of the aryl-CH2CF3 bond. [ABSTRACT FROM AUTHOR]

The direct synthesisof pentafluoroethyl copper (CuC2F5) from a cuprate reagent and ethyl pentafluoropropionateas one of the most economical and useful pentafluoroethylsources was accomplished. The advantages of this method are; all thereagents employed are low-cost and operationally simple, and the CuC2F5reagent is prepared in virtually quantitativeyield. Furthermore, the CuC2F5reagent preparedwas successfully applied to two types of pentafluoroethylationswith arylboronic acids and aryl bromides to provide the pentafluoroethylatedaromatic products in good-to-excellent yields, including large scaleoperations. [ABSTRACT FROM AUTHOR]

Conformationally restricted perhydrobenzoxazines have been demonstrated to be good chiral ligands for one-pot asymmetric ethylation/epoxidation, and the unprecedented arylation/epoxidation of trisubstituted α,β-unsaturated aldehydes. The scope of the reaction has been studied and a wide set of substrates with allylic strain of different nature has been explored, obtaining good or total diastereoselectivities in all cases. The enantiocontrol was good or high for the ethylation/epoxidation reaction, whereas it remained at moderate or good levels for the arylation/epoxidation. The reaction is general for trisubstituted enals, and alkylic and aromatic substituents are tolerated at both the α- and β-position of the unsaturated aldehyde; however, disubstituted enals remain challenging substrates. When the one-pot and two-pot protocols were compared, no significant differences concerning the stereocontrol were found, so the advantages of the one-pot procedure are clear. [ABSTRACT FROM AUTHOR]

Abstract: A new β-diketone ligand, 1-(9-ethyl-6,8-dimethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dione was synthesized by four step reaction (Suzuki–Miyaura cross-coupling, Cadogan cyclization, N-ethylation and Claisen condensation reaction) from 1-(4-bromo-3-nitrophenyl)ethanone and 3,5-dimthylphenylboronic acid. Deprotonated 1-(9-ethyl-6,8-dimethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dionate (L−1) and 1,10-phenanthroline (phen) coordinated to europium ion to yield a new europium(III) complex, EuL3[phen]. The Eu(III) complex was characterized by elementary analysis, IR, 1H NMR, 13C NMR , UV–Vis absorption spectroscopy, thermogravimetric analysis (TGA) and photoluminescence measurements. TGA shows that the decomposition temperature of the complex EuL3[phen] is up to 320°C. Photoluminescence measurement results indicate that the Eu(III) complex exhibits intense red emission and extends its excitation band blue light region. Red emission LEDs were successfully fabricated by precoating complex EuL3[phen] onto 460nm blue-emitting InGaN chip. The europium complex based on depronated 1-(9-ethyl-6,8-dimethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dionate is a very interesting blue light excitable red emission material, which can be applied in many fields without UV radiation. [Copyright &y& Elsevier]

An efficient synthesis of pyrrole diesters from readily available aromatic, benzylic, and aliphatic nitriles with ethyl bromoacetate takes place if the amount of the catalyst is 50 mol%. [ABSTRACT FROM AUTHOR]

The synthesis of stable, non-hygroscopic, and easy-to-handle zwitterionic title structures from heterocyclic arenes is presented. [ABSTRACT FROM AUTHOR]