Br?nsted acid catalyzed addition of N^1-p-methyl toluenesulfonyl triazole to olefins for the preparation of N^2-alkyl 1,2,3-triazoles with high N^2-selectivity

An efficient new method has been developed to synthesize N2‐alkyl 1,2,3‐triazole products by tol‐uenesulfonic acid （TsOH） catalyzed addition of N1‐Ts substituted 1,2,3‐triazoles to olefins. The reac‐tions of monosubstituted and unsubstituted triazole substrates with various olefins, including vinyl esters, are explored.

A CONVENIENT SYNTHESIS OF 8-ALKYL S'-ALKYL (ARYL) DITHIOPHOSPHORIC ACID DERIVATIVES

The chlorination of S-alkyl(aryl) 0,0-dialkyl dithiophosphates with phosphorus oxychloride proceeds with isomerization to give S-alkyl S'-alkyl(aryl) dithiophosphorochtoridates, which react further with various nucleophiles in the presence of base to give the title compounds

Solvent and Temperature Effects on Spectral Properties of Two Poly(3-alkyl)thiophene Derivatives

Two alkyl substituted polythiophene derivatives: poly(3-hexylthiophene)(P3HT) and poly(3-decylthiophene)(P3DT), have synthesized by oxidation coupling polymerization of 3-alkylthiophene using iron(III) chloride as catalyst in chloroform. While both polymers in pure chloroform solution have maximum absorption at approximately same wavelength of 440nm, they behave differently with respect to changes observed on their UV-visible and photoluminescence spectra when the quality of the poor solvent is changed in good solvent (chloroform) / poor solvent (methanol) mixtures. With increasing volume fraction of methanol in mixtures, the absorption spectra of P3HT and P3DT red-shift, peaking at maximum wavelength of 495nm (P3HT) and 510nm(P3DT). Furthermore, the absorption spectra of the two polymers in chloroform blue-shift as the temperature rises. P3HT shows 4.73nm blue-shifts at 50℃ in contrast to the case at 20℃, while P3DT blue-shifts about 5.04nm. The photoluminescence spectra of the two polymers in mixed solution are also investigated, which show that the luminescence spectra shift to longer wavelength with an accompanying drop in the PL intensity as methanol is increased. The absorption and emission spectra of the two polymers in a poor solvent and a thin film are similar, which indicate that a similar longer conjugation length in the two cases. It could conclude that the polymers exist almost the same conformations and aggregations in both a poor solvent and a thin film. P3DT exhibits more sensitive spectra properties (big red-shifts in both absorption and luminescence spectra in poor solvents and large blue-shifts at high temperature) with contrast to P3HT, which imply that long side alkyl may improve the chromic properties of the polymer.

Microwave-prompted rapid and efficient synthesis of 3-alkyl substituted imidazo[1,5-a]pyridines

Under regular heating and microwave irradiation, 3-alkyl substituted imidazo[1,5-a] pyridines were synthesized from 2,2＇- pyridil, di-2-pyridyl ketone and aliphatic aldehydes in the presence of ammonium acetate and acetic acid. Compared to the traditional heating condition, the reaction time under microwave irradiation was shorter and 3-alkyl imidazo[1,5-a]pyddines were given in higher yield.

Room-Temperature Electroreductiveα-Alkylation of N-Heteroarenes with Styrenes

Despite their interesting applications,direct and diverse syntheses of aryl-fused 2-alkyl cyclic amines still remain challenging.Here,the concept of incorporating a C–C coupling process into the N-heteroaryl reduction was successfully applied to fulfill such a synthetic purpose.Due to our use of controllable electroreduction coupled with proton abstraction,we can report a room-temperature reductiveα-alkylation of the inert N-heteroarenes with abundantly available styrenes in an undivided Zn(+)/C(−)cell.This proceeds with good substrate compatibility and operational simplicity,utilizes cost-effective sacrificial Zn-anode,exhibits high selectivity,and does not need pressurized H2 gas and transition-metal catalysts.This current work offers a useful platform for direct construction of valuable aryl-fused 2-alkyl cyclic amines that are difficult to access with conventional methods.

Selective N-Alkylation of 2-Amino-4H-chromene-3-carbonitrile Derivatives with Alcohols Catalyzed by AlCl3 Under the Assistance of CH3COOH

A highly efficient and selective N-alkylation reaction of 2-amino-4H-chromene-3-carbonitrile derivatives using various alcohols as alkylation agent were developed in the presence of AlCl3 as a catalyst as well as CH3COOH as an additive,in which the cyano group kept inert and the amino group was alkylated in high yields.All the target products were characterized and determined by infrared(IR),1H NMR,13C NMR,and HRMS.And the X-ray structure of product 3ab was obtained.A bimolecular reaction mechanism catalyzed by AlCl3 was proposed under the assistance of CH3COOH.

Lignin-derived Zn single atom/N-codoped porous carbon forα-alkylation of aromatic ketones with alcohols via borrowing hydrogen strategy

A green and scalable strategy has been developed for the synthesis of lignin-derived Zn single atom/N-codoped porous carbon(LCN@Zn-SAC)containing similar ZnNx sites with carbonic anhydrases.This catalyst exhibits superior activity on theα-alkylation of ketones with alcohols via borrowing hydrogen strategy(TON up to 15 h^(−1))than most of previously reported works.The dehydrogenation of benzyl alcohol is the rate-determining step based on kinetic experiment results.According to experimental and theoretical calculation results,Zn electron density is inversely proportional to reaction energy barriers,because Zn sites with less positive charge(ZnN_(4) and ZnN_(3)C)in Zn-SACs display better borrowing hydrogen ability than other Zn sites.Furthermore,this catalyst can be recycled by simple centrifugation,which can be reused at least 8 runs with no obvious lose in activity.To the best of our knowledge,this is the first example of non-noble metal-SAC-catalyzedα-alkylation via borrowing hydrogen strategy.

Facile Syntheses of 3-Isopentenyl Flavone and 3-Geranyl Flavone

Although there was a strong steric effect,isopentenyl and geranyl moieties were successfully introduced into C3 position in flavone skeleton so as to synthesize the 3-isopentenyl flavone and 3-geranyl flavone under two cyclization conditions（AcOH/HCl and concentrated H 2 SO 4 /MeOH） in this report.It was found that the optimum cyclization conditions for 3-isopentenyl flavone and 3-geranyl flavone were,respectively,AcOH/HCl and H 2 SO 4 /MeOH.Furthermore,the donating electron ability is in the sequence 3-geranyl flavone3-isopentenyl flavone according to the density functional theory（DFT） calculations,suggesting the longer alkyl chain at 3-position would be more favorable for enhancing the donating electron ability.The present synthetic routes might reveal potential applicability in our continued studies on the total syntheses of other natural 3-alkyl flavonoids.

Solid Phase Synthesis of 1,4-Disubstituted 1,2,3-Triazole from Polystyrene-supported Selenium Resin

We report here a solid-phase synthesis of 1, 4-disubstituted 1, 2, 3-triazole using polystyrene-supported selenium resin. The resin used here not only works as a simple linker, but also assists the crucial α-alkylation reaction and selenoxide syn-elimimation, which ensures the purity of the products.

PREPARATION AND CHARACTERIZATION OF HUMIDITY SENSOR BASED ON POLY(3-ALKYL)PYRROLE CONTAINING PHOSPHONIC ACID GROUPS

Poly（3-alkyl）pyrroles containing phosphonic acid groups with different alkyl segment lengths were chemical synthesized and the properties were measured by FTIR and UV-Vis spectroscopy. FTIR and UV-Vis results showed that the synthesized polymers were in a low doping level through chemical polymerization. By spin-coating on the surface of substrates, the polymer can be used as a humidity sensor. The change of DC electric current of the polypyrroles varies with the chain length of the alkyl substituents. The capacitance increases with the increase of the humidity and resistance decreases with the increase of humidity. This result is different from that ofpolypyrrole without alkyl substituents due to the influence of the phosphonic acid group. The sensor showed the resistive-type at high relative humidity, and the capacitive- type at the low relative humidity. The sensor exhibited very fast response to the change of environment humidity.

Is the metal involved or not? A computational study of Cu(I)-catalyzed [4+1] annulation of vinyl indole and carbene precursor

The Cu(I)-catalyzed [4 + 1] annulation of vinyl indoles and a carbene precursor is a powerful method for constructing cyclopentaindole derivatives. Density functional theory(DFT) calculations were used to elucidate the mechanism and regioselectivity of this reaction. After Cu-assisted indole C3-alkylation, direct1,5-annulation was favored over the Cu-assisted annulation pathway. Furthermore, the regioselectivity for1,5-annulation was attributed to the generated five-membered-ring product being more stable than the three-membered-ring product from 1,3-annulation, which was the kinetically favored pathway.

A Formal Synthesis of Betamethasone

A formal synthesis of betamethasone from 5α-pregnane-3β,16β,20S-triol is described.Key transformations are a bromination-acetylation of triol,an SN2 reaction of the resulting C16α-bromide with dimethylcopperlithium to get the required C16β-methyl group,and a double hydroxylation to prepare the dihydroxyacetone side chain.