2,4,6-Trichloro-1,3,5-triazine catalyzed synthesis of thiiranes from oxiranes under solvent-free and mild conditions

A simple, mild and efficient method has been developed for the synthesis of thiiranes from epoxides using a catalytic amount of 2,4,6-trichloro-1,3,5-triazine under solvent-free conditions.     

Nafion®‐supported oxovanadium‐catalyzed hydrophosphonylation of aldehydes under solventless conditions

A Nafion® resin‐supported oxovanadium(IV) catalyst was readily prepared via ion‐exchange method. This solid vanadyl perfluorinated sulfonate catalyst was used as an efficient and recoverable catalyst for the hydrophosphonylation of various aldehydes under solventless conditions at room temperature. The catalyst could be recovered by simple filtration and reused without a significant loss of activity. Copyright © 2012 John Wiley & Sons, Ltd.     

Ruthenium‐catalyzed biginelli condensation: A simple and efficient one‐pot synthesis of 3,4‐dihydropyrimidin‐2(1H)‐ones under mild reaction conditions

Ruthenium trichloride was found to be an efficient catalyst for the first time for the synthesis of a variety of 3,4‐dihydropyrimidin‐2(1H)‐ones by cyclocondensation of an aldehyde, β‐dicarbonyl compound and urea in excellent yields under mild reaction conditions.     

Et3N catalyzed the diastereoselective synthesis of functionalized cyclohexanones by condensation of acetoacetanilide and various aldehydes in mild conditions

Research on Chemical Intermediates - A facile synthetic strategy has been reported for the diastereoselective synthesis of...     

Bis(1,3,5‐triazine‐2,4,6‐triamine‐κN1)silver(I) nitrate

The title compound, [Ag(C₃H₆N₆)₂]NO₃, has an alternating two‐dimensional bilayer structure supported by extensive hydrogen bonds. The [Ag(melamine)₂]⁺ cationic monomers (melamine is 1,3,5‐triazine‐2,4,6‐triamine) are connected via N—H...N hydrogen bonds to form two‐dimensional sheets. Nitrate groups are sandwiched between two sheets through N—H...O hydrogen bonds. An almost perfectly linear coordination geometry is found for the Ag^I ions. The triazine ligands are slightly distorted due to π–π interactions.     

Triple condensation of aryl methyl ketones catalyzed by amine and trifluoroacetic acid: straightforward access to 1,3,5-triarylbenzenes under mild conditions

An efficient triple condensation reaction of aryl methyl ketones catalyzed by ethylenediamine and trifluoroacetic acid was reported. A broad scope of 1,3,5-triarylbenzenes was obtained in good to excellent yields. The reaction provides a novel and practical approach to access organic materials of polycyclic aromatic hydrocarbons under mild conditions.     

DFT Study of the Group Interactions in 1,3,5‐Triamino‐2,4,6‐Trinitrobenzene and 1,3,5‐Triamino‐2,4,6‐Tridifluoroaminobenzene

Density functional calculations on isodesmic disproportionation reactions of 1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB) and 1,3,5‐triamino‐2,4,6‐tridifluoroaminobenzene (TATDB) indicate that the interaction between nitro groups on meta carbons of TATB, which brings about unstability to the molecule, is surprisingly larger than that between difluroamino groups in TATDB. The electron‐withdrawing and electron‐donating groups generate large positive and very small negative values of E_{disproportion}, respectively. When both electron‐withdrawing and electron‐donating groups are attached to the benzene skeleton at the same time, large negative disproportionation energy is produced, which stabilizes the derivatives. The values of E_{disproportion} for TATB and TATDB are predicted to be ‐48.03 kJ/mol and ‐63.54 kJ/mol, respectively, indicating that the total interaction among groups with stabilization effects in TATDB is larger than that in TATB. The large difference of the E_{disproportion} values between TATB and TATDB is derived from the large difference between the interactions of the meta‐nitro group and those of meta‐difluoroamino groups. The energy barriers for the C‐N internal rotation of NO₂ group and NF₂ groups are 74.7 kJ/mol and 185.8 kJ/mol for TATB and TATDB, respectively. The large energy barrier for the rotation of the NF₂ group is caused by its stabilization interaction with neighbor amino groups, instead of steric effects. When the number of pairs of amino‐nitro or amino‐difluoroamino groups increases, there are more negative charges on the NO₂/NF₂ groups and on the O/F atoms.     

Silica‐supported synthesis of some 1,3,5‐trisubstituted 2‐pyrazolines under solvent‐free and microwave irradiation conditions

A simple method for the synthesis of 2‐pyrazolines is described which occurs on silica surface under solvent‐free conditions within 110‐180 sec using microwave irradiation. The results obtained indicate that the use of silica gel as a support in pyrazoline formation reactions can have a profound effect on reaction rates and yields and cause cleaner reaction conditions.     

Knoevenagel condensation reactions catalyzed by nitrogen-containing mesoporous carbon materials under mild reaction conditions

Research on Chemical Intermediates - A series of nitrogen-containing ordered mesoporous carbon (NOMC) materials have been prepared by a convenient soft-templating method. The physicochemical...     

Pyrrole synthesis in ionic liquids by Paal-Knorr condensation under mild conditions

Paal-Knorr condensation of 2,5-hexandione with primary amines was successfully carried out in ionic liquids. Through investigating different ionic liquids, different reaction times, the reaction, using ionic liquids as solvent, exhibited simple product isolation procedure, improved yields and exclusive selectivity and the mild conditions and the avoidance of using toxic catalysts are also its special features. Recovery and reuse of ionic liquid are also satisfactory.     

Stereoselective synthesis of pseudoglycosides catalyzed by TeCl4 under mild conditions

Catalytic amounts of tellurium(IV) tetrachloride were used to promote the O-glycosylation of 3,4,6-tri-O-acetyl-d-glucal to give the corresponding 2,3-unsaturated-O-glycosides. With simple alcohols, the desired compounds were obtained in good yields and excellent anomeric selectivity in a short reaction time using only 2 mol % of the catalyst. The application of the method in the synthesis of a small set of glycopyranosides with rigid or flexible linkers gave the corresponding α anomers as products in good yields. Further applications of some of the synthesized compounds in allylation reaction of aldehydes gave the corresponding homoallylic alcohols in good yields.     

Preparation of amidoalkyl naphthols by a three-component reaction catalyzed by 2,4,6-trichloro-1,3,5-triazine under solvent-free conditions

Abstract  An efficient one-pot synthesis of amidoalkyl naphthols is described. This involves the three-component reaction of 2-naphthol, aromatic aldehydes and amide or urea in the presence of a catalytic amount of 2,4,6-trichloro-1,3,5-triazine (TCT, cyanuric chloride) under solvent-free conditions. Graphical abstract        

Cu‐catalyzed coupling of arylsulfinic salts with arylsilanes under mild conditions

Arylsilanes were efficiently coupled with arylsulfinic salts for the first time under mild conditions. Diarylsulfone derivatives were easily synthesized in high yields with the assistance of nitrogen‐containing ligands and KF. The transformation is simple and efficient and the starting materials are readily available. Copyright © 2014 John Wiley & Sons, Ltd.     

Comparative theoretical synthesis of high‐energy density materials 2,4,6‐trinitro‐1,3,5‐triazine

In this study, the optimal synthetic route for 2,4,6‐trinitro‐1,3,5‐triazine (TNTA) was investigated. The synthesis of TNTA was performed using cyanamide (H₂NCN) as a starting material. In the first stage, a radical addition reaction was used to generate melamine, which is the precursor of TNTA. In addition, a gaseous nitration reaction using nitrogen dioxide radicals (^?NO₂) as the nitration agent was used to gradually induce radical substitutions to convert dicyandiamide (H₂NCN)₂ to melamine (H₂NCN)₃. Additional nitration steps lead to triaminocyanide and, ultimately, TNTA. In addition, nitryl cyanide (O₂NCN) was also tested as a starting material for radical addition to generate dinitryl cyanide (O₂NCN)₂, trinitryl cyanide (O₂NCN)₃, and, finally, TNTA. The activation energy barrier in each of the reaction steps as well as the various synthetic routes were compared to provide insight into the design of more feasible routes for the synthesis of TNTA. © 2014 Wiley Periodicals, Inc.     

Knoevenagel condensation of aldehydes with active methylene compounds catalyzed by MgC2O4/SiO2 under microwave irradiation and solvent-free conditions

MgC₂O₄/SiO₂ catalyzes the efficient Knoevenagel condensation of aldehydes with active methylene compounds in solvent-free conditions under microwave irradiation to give alkenes derivatives in excellent yields. MgC₂O₄/SiO₂ can be reusable for Knoevenagel condensation. However, ketones have been found to be unsatisfactory in the reaction under the same conditions.     

Unprecedented Trinuclear AgI Complex with 2,4,6‐Tris(2‐pyrimidyl)‐1,3,5‐triazine as an Efficient Catalyst for the Aziridination of Olefins

An unprecedented trinuclear heteroleptic Ag^I complex was isolated using a stable multidentate 2,4,6‐tris(2‐pyrimidyl)‐1,3,5‐triazine (TPymT) ligand. The obtained compound is an efficient catalyst for the direct aziridination of terminal olefins.     

Study of interfacial chemistry on direct curing adhesion between Ni–P plating and rubber using 1,3,5‐triazine‐2,4,6‐trithiol monosodium salt

Direct adhesion between Ni–P‐plated iron and acrylonitrile–butadiene rubber, hydrogenated acrylonitrile–butadiene rubber and ethylene–propylene rubber was successful using 1,3,5‐triazine‐2,4,6‐trithiol monosodium salt (TTN) without any adhesive. Peel strength in the adherends was influenced by the amount of TTN employed. The interfacial structure between Ni–P‐plated iron and curing rubbers has been investigated with x‐ray microanalysis, x‐ray photoelectron spectroscopy and scanning electron microscopy. The TTN derivatives gathered locally at the interface between the Ni–P‐plated iron and curing rubber adherends. The TTN layer located near the interface is referred to as a reinforcement layer. This layer was in general ～70 nm thick and consisted of composites of the Ni salt of TTN. The TTN is thought to work as a binder that bonds between Ni–P‐plated iron and rubber chains. The single bonds between both Ni–P‐plated iron and rubber TTN was confirmed from Kraus plots and model experiments using TTN. Copyright © 2003 John Wiley & Sons, Ltd.     

Phenylphosphinic acid‐catalyzed synthesis of 6‐unsubstituted dihydropyrimidinones under solvent‐free conditions

Phenylphosphinic acid is found to catalyze the three‐component condensation of an aldehyde, enaminone, and urea or thiourea to afford the corresponding 6‐unsubstituted dihydropyrimidinones in high to excellent yields. This methodology is simple and fast synthetic route for the preparation of interesting class of heterocycles.     

无溶剂条件下硅胶固载磷酸催化环己酮与芳香醛的缩合反应

以硅胶(mSiO2·nH2O)固载磷酸为催化剂,在无溶剂条件下催化环已酮与芳香醛的Cross-Aldol缩合反应,得到7个相应的α,β不饱和羰基化合物,反应时间短(60～150 min),产率高(73.4％ ～ 92.7％).该方法操作简单,催化剂可重复使用,且对环境友好.     

Efficient regioselective synthesis of 4‐ and 5‐substituted isoxazoles under thermal and microwave conditions

The [2+3] cycloaddition reaction between nitrile oxides 2 and the captodative olefins 1 or the methyl crotonate derivatives 4 is regioselective and leads to the formation of the 5‐substituted amino‐isoxazole 3 or the 4‐substituted methoxycarbonyl‐isoxazole 5 derivatives, respectively. All these reactions are greatly accelerated by microwave irradiation without changing their regioselectivity with respect to the thermal conditions.