A novel biomimetic condensation of 2-deoxyribose, aryl amine and acetyl acetone to bicyclic aminols catalyzed by InCl3

2-Deoxyribose, an aryl amine and acetyl acetone undergo smooth cyclocondensation in the presence of 10 mol % of InCl₃ under mild conditions to afford the corresponding sugar-derived bicyclic aminols in good yields with moderate diastereoselectivity. This reaction is reminiscent of the celebrated tropinone synthesis of Robinson. The structures of the products are established by using various NMR experiments and X-ray crystallographic studies.     

(S)-Pyrrolidine sulfonamide catalyzed asymmetric direct aldol reactions of aryl methyl ketones with aryl aldehydes

A (S)-pyrrolidine sulfonamide catalyzed asymmetric direct aldol reaction of aryl methyl ketones with aromatic aldehydes has been developed with moderate to good enantioselectivities. The study considerably broadens the substrate scope of chiral amines promoted aldol processes.     

Microwave-assisted Pd(OH)2-catalyzed direct C−H arylation of free-(NH2) adenines with aryl halides

A direct C−H arylation of free-(NH₂) adenines using Pd(OH)₂/C (Pearlman’s catalyst) and stoichiometric amount of copper iodide under ligandless microwave activation is described. This new protocol proved to be highly effective to synthesize a variety of 8-aryladenine derivatives 3 without prior protection of the amino substituent. The arylation reaction takes place rapidly within few minutes and allows the coupling to proceed regioselectively at the 8-position with a wide range of aryl halides including aryl iodides, bromides and the less reactive aryl chlorides.     

Flame retardancy mechanisms of aryl phosphates in combination with boehmite in bisphenol A polycarbonate/acrylonitrile-butadiene-styrene blends

The influence of nano-dispersed 5 wt.% boehmite (AlOOH) and 5 wt.% AlOOH combined with bisphenol A bis(diphenyl phosphate) (BDP) in bisphenol A polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) + poly(tetrafluoroethylene) (PTFE), and 1 wt.% AlOOH with and without BDP, resorcinol bis(diphenyl phosphate) (RDP), and triphenyl phosphate (TPP), on PC/ABS + PTFE has been investigated. Possible flame retardancy mechanisms are revealed. Thermogravimetry (TG) and evolved gas analysis (TG-FTIR) are used to study pyrolysis, a cone calorimeter applying different external heat fluxes is used to investigate fire behaviour, and LOI and UL 94 are used to investigate flammability. Fire residues were investigated using ATR-FTIR.Adding 5 wt.% AlOOH decreases the peak heat release rate, as also has been reported for polymer nanocomposites with other layered structures. AlOOH releases water, and adding 5 wt.% AlOOH crucially influences thermal decomposition by enhancing the hydrolysis of PC and of BDP. For PC/ABS + PTFE + BDP + 5 wt.% AlOOH, the formation of AlPO₄, for instance, results in antagonistic effects on the charring of PC + BDP, whereas synergy is observed in LOI. When only 1 wt.% AlOOH is added to the PC/ABS + PTFE with and without BDP, RDP and TPP, respectively, no significant influence is observed on thermal decomposition, UL 94, LOI or performance in the cone calorimeter.     

A Simple and Efficient Method for the Oxidation of Aryl Substituted Semicarbazide with NaNO2/NaHSO4·H2O/SiO2 under Mild Conditions

In this paper, eighteen aryl substituted semicarbazide underwent efficient oxidation to aryl azo compounds using NaNO₂/NaHSO₄·H₂O/SiO₂ under mild conditions with excellent yields.     

Cascade synthesis of dihydrobenzofuran via Claisen rearrangement of allyl aryl ethers using FeCl3/MCM-41 catalyst

Dihydrobenzofuran as one of the active ingredients of the naturally occurring motif is synthesized by using in situ generation of ortho allyl phenols. Aryl allyl ethers on reacting with catalytic amounts of non noble metal iron (III) chloride supported on MCM-41 under moderate reaction conditions yield dihydrobenzofuran. First step via Claisen rearrangement gives ortho allyl phenol followed by its in situ cyclization to yield dihydrobenzofuran in very good yields. Both Lewis as well as Brønsted acidity of the catalyst as evidenced by Py-FTIR studies was found to catalyze the cascade synthesis of dihydrobenzofuran. The scope of the present strategy was successfully demonstrated for several substrates with varying electronic effects for the synthesis of corresponding dihydrobenzofuran with high yields in a range of 71–86%.     

Monodentate phosphorus-coordinated palladium(Ⅱ)complexes as new catalyst for Mizoroki-Heck reaction of aryl halides with electron-deficient olefins

Four novel monodentate phosphorus-coordinated palladium(Ⅱ) complexes derived from 3,5-disubstituted-1H-1,2,4-diazaphospholes were developed as efficient catalyst for Mizoroki-Heck reactions of aryl halides with electron-deficient olefins. The role of these monophosphine ligands in catalysis was illustrated by control experiments using Pd salt and ligands as combined catalyst.     

Synthesis,crystal structure,and insecticidal evaluation of novel aryl pyrazole compounds containing aminophosphonate moiety

A series of novel aryl pyrazole derivatives containing aminophosphonate were designed and synthesized on the basis of the commercial insecticide Fipronil. Their structures were confirmed by ¹H NMR, FT-IR, elemental analysis, and compound 4 m was characterized by a single crystal X-ray diffraction analysis. The results of the preliminary bioassays showed that title compounds exhibited satisfactory insecticidal activities against Culex pipiens and Musca domestica. The introduction of an electron-withdrawing group to the para-position of the benzene ring was essential for high bioactivity.     

Copper nitrate–catalyzed α-bromination of aryl ketones with hydrobromic acid

An efficient method for α-bromination of aryl ketones, using the combination of molecular oxygen and aqueous hydrobromic acid as a brominating agent in the presence of the copper nitrate, has been developed. This catalytic system, which uses cheap and readily available reactants, shows good atom economy with water as the only by-product.