Comparative study on syntheses of 1,3,5-trimethoxy-1,3,5-triisopropylcyclotrisiloxane

1,3,5-Trimethoxy-1,3,5-triisopropylcyclotrisiloxane (2) was prepared from 1,3,5-triisopropyl-1,3,5-tri-o-tolylcyclotrisiloxane—(1) according to three kinds of methods as follows: the dearylchlorination of 1 using HCl/AlCl₃, which led to prepare 2 includes a very slight amount of aluminum species as impurities, the dearylbromination using Br₂, which simultaneously brought unnecessary bromination without isolated 2, and the dearylation using TfOH, which efficiently gave 2 of a high purity without metals of contamination.     

Michael Reaction of 2,4-Dioxohexahydro-1,3,5-triazine

With the extensive investigation of the Michael reaction, not the methylene compounds activated by electron withdrawing group[1,2] but other activated unsaturated compounds containing such as activate N-H or O-H have been used as Michael acceptor.[3,4] However, the research on the Michael reaction of 2,4-dioxohexahydro-1,3,5-triazine (DHT) has not been reported. After the systematic researches on the substitution reactions of DHT, we first report the Michael reaction of DHT with acrylic esters in this paper.     

DFT Study of Hydrogen-Bonded 1,3,5-Triazine-Water Complexes

The 1,3,5-triazine-water hydrogen bonding interactions have been investigated using the density functional theory B3LYP method and 6-31 ＋＋G^＊＊ basis, obtaining one, two and seven energy minima of the ground states for the 1,3,5-triazine-water, 1,3,5-triazine-（water）2 and 1,3,5-triazine-（water）3 complexes respectively. The fully optimized geometries and binding energies were reported for the various stationary points. The global minima of 1,3,5-triazine-（water）2 and 1,3,5-triazine-（water）3 complexes have a hydrogen bond N…H-O and a chain of water molecules, terminated by a hydrogen bond O…H-C. The binding energies are 13.38, 39.52 and 67.79 kJ/mol for the most stable 1,3,5-triazine-water, 1,3,5-triazine-（water）2 and 1,3,5-triazine-（water）3 complexes respectively, after the basis set superposition error and zero point energy corrections. The H-O symmetric stretching modes of water in the complexes are red-shifted relative to those of the monomer water. In addition, the NBO analysis indicates that inter-molecule charge transfer is 0.02145 e, 0.02501 e and 0.02777 e for the most stable 1 ： 1, 1 ： 2 and 1 ： 3 complexes between 1,3,5-triazine and water, respectively.     

TBPA＋ mediated aromatization of 1,3,5-trisubstituted pyrazolines

1,3,5-Trisubstituted pyrazolines were oxidized to the corresponding pyrazoles in high yield with tris（4-bromophenyl）aminium （TBPA＊＊） hexachloroantimonate in chloroform at room temperature.     

Synthesis of 2-arylpyrrolidines by reaction of γ-ureidoacetals with benzene-1,3,5-triol

New 2,2′-(2,4,6-trihydroxybenzene-1,3-diyl)dipyrrolidine derivatives have been synthesized by reaction of benzene-1,3,5-triol (phloroglucinol) with γ-ureidoacetals in the presence of trifluoroacetic acid as catalyst.     

Synthesis of α-Amino Tertiary Alkylperoxides by Lewis Acid-Catalyzed Peroxidation of 1,3,5-Triazines

α-Substituted peroxides have been found in natural products and are widely used as anti-malarial agents. Zn(OTf)₂-catalyzed peroxidation of 1,3,5-triazines has been developed, accessing diversely substituted α-amino tertiary alkylperoxides with high efficiency. Mechanistic investigations and useful synthetic application of the products have also been presented.     

Anionic σ-complexes of 1,3,5-tris(fluorosulfonyl)benzene

We have found that symmetrical benzene trisulfonic-acid trifluoride 1 is able to undergo nucleophilic addition at free positions on the aromatic ring. Its reactions with sodium sulfite, morpholine and carbanions of malonic and acetoacetic esters, dimedone and nitromethane lead to the formation of comparatively stable anionic σ-complexes 3-8.     

Tricarbamate of 1,3,5‐Triaminobenzene via Curtius Rearrangement of Trimesic Acid and Subsequent Nitration

The triethyl tricarbamate of 1,3,5‐triaminobenzene was prepared from trimesic acid in five steps with 70% overall yield. The tricarbamate underwent nitration to give the mono‐, di‐, or trinitro analogs in excellent yield.     

Safer Conditions for the Curtius Rearrangement of 1,3,5‐Benzenetricarboxylic Acid

A rapid method to prepare 1,3,5‐triaminobenzene and its derivatives is the tris‐Curtius rearrangment of 1,3,5‐benzenetricarboxylic acid. The hazards associated with the acyl azide route are minimized by using 1,2‐dichloroethane as solvent. A second method that avoids acyl azide preparation uses diphenylphosphoryl azide to yield the tricarbamate in one step.     

Novel Method for the Synthesis of 1,3,5‐Triarylbenzenes from Ketones

Treatment of aryl ketones with p‐toluenesulfinic acid and a catalytic amount of tin tetrachloride anhydrous (5%) in 1‐pentanol gives good yields of 1,3,5‐triarylbenzenes.     

Stereoselective Synthesis of 1,6-Dichloro-1,3,5-Hexatriene Derivatives by Mcmurry Coupling of β-Chloroacrylaldehyde Derivatives

A highly stereoselective synthesis of 1,6-dichloro-1,3,5-hexatriene derivatives by McMurry coupling of β-chloroacrylaldehydes have been developed.     

Improved Preparation of 3,17β-Dihydroxyoestra-1,3,5(10),6-tetraene

The title compound is prepared in good yield via the tosylhydrazone of 3,17β-diacetoxyoestra-1,3,5(10)-triene-6-one (Shapiro reaction)     

Effect of Particle Size and Capping on Photoluminescence Quantum Efficiency of 1,3,5-Triphenyl-2-pyrazoline Nanocrystals

Organic nanocrystals of 1,3,5-triphenyl-2-pyrazoline(TPP) with a series of sizes were synthesized by reprecipitation method.The luminescence quantum efficiency of TPP nanocrystals increases from 24.2% for the nanocrystals with an average size of 300nm to 34.6% for those with an average size of 20nm.Surface capping by polyvinyl pyrrolidone(PVP) will improve the quantum efficiency of TPP nanocrystals.The size-dependence and capping-induced variation of the luminescence quantum efficiency was elucidated in viewpoint of aggregation quenching and the equilibrium between the TPP monomers and the aggregates in TPP nanocrystals.     

Microwave Assisted Synthesis of Fluorinated Hexahydro 1,3,5‐Triazine Derivatives in Aqueous Medium and One Pot Synthesis of 1,2,4‐Triazolo(4,3‐a)1,3,5‐triazines

Abstract

A multi‐component condensation of substituted phenylthiourea/urea, aqueous formaldehyde and substituted aromatic/heterocyclic amines lead to 2‐thioxohexahydro‐1,3,5‐triazines (4) in aqueous medium under microwave irradiation in 30–60 sec in quantitative yield with reasonable purity. Further, triazolo[4,3‐a]triazines were also prepared by a one‐pot reaction of ‘in situ’ synthesized triazinyl hydrazine (7) with CS₂ (9).     

Synthesis and magnetism of μ-1,3,5-benzenetricarboxylatocopper(II) trinuclear complexes

Summary Three new Cu^II trinuclear complexes, namely [Cu₃(BZT)(phen)₃(ClO₄)₃]·6H₂O (1), [Cu₃(BZT)(Nphen)₃ (ClO₄)₃]·6H₂O (2) and [Cu₃(BZT)(bipy)₃ (ClO₄)₃]·3H₂O (3) (BZT) = 1,3,5-benzenetricarboxylato, phen = 1,10-phenanthroline, Nphen = 5-nitro-1,10-phenanthroline, bipy = 2,2-bipyridyl, have been synthesized, with 1,3,5-benzenetricarboxylato as the bridged ligand, and characterized by elemental analysis, and i.r. and electronic reflection spectra. We propose that the complexes have an extended 1,3,5-benzenetricarboxylatobridged structure containing three Cu^II atoms. The variable-temperature magnetic susceptibilities of the complexes were measured in the 77–300 K range. The magnetic coupling parameters are consistent with an antiferromagnetic exchange model based on the Hamiltonian operator [=–2J( _{1 2}+ _{1 3}+ _{2 3}, where S ₁=S ₂=S ₃=1/2, giving the antiferromagnetic coupling parameters of 2J = – 18.6 cm^-1 for (1)–(3).     

Syntheses and Anti-lung Cancer Effects of Two Novel Dy(Ⅲ) Complexes Based on 1,3,5-Benzenetricarbocylic Acid and 1,3,5-Benzenetrisbenzoic Acid,respectively

The reactions of 1,3,5-benzenetricarbocylic acid(H3BTC) and 1,3,5-benzenetrisbenzoic acid(H3BTB) with Dy(NO3)3·6H2O afford two novel Dy(III) coordination polymers respectively, Dy(BTC)(H_2O)DMF(1) and [Dy(BTB)(Et OH)](DMF)(2)(DMF = N,N-dimethylformamide). 1 shows a 3D framework composed of available Lewis-acid metal sites which are occupied by the coordinated water molecules, and 2 features a noninterpenetrated open 3D framework with a 5-connected bnn hexagonal topology possessing the point symbol(46.64). In addition, in vitro antitumor activities of compounds 1 and 2 on three human lung cancer cells(H1975, HCC827 and A549) were further determined.     

Acid-Catalyzed Condensation of 1,3,5-Triphenylpentane-1,5-dione with Benzaldehyde—A New Domino Reaction

Aldol-like condensation of 1,3,5-diphenyl-1,5-pentanedione with benzaldehyde in the presence of acids is accompanied by the Nazarov cyclization with formation of substituted indanone or indeno[1,2-b]pyran in a one-pot process.     

A model for predicting the solubility of 1,3,5-trinitro-1,3,5-s-triazine (RDX) in supercritical CO2: isothermal–isobaric Monte Carlo simulations

Isothermal–isobaric Monte Carlo (NPT-MC) simulations and the Widom test particle method were used to predict the solubility of the explosive 1,3,5-trinitro-1,3,5-s-triazine (RDX) in supercritical CO₂. A Lennard–Jones potential energy function was chosen to describe the interaction between RDX and CO₂, and calibrated using two experimental solubility values. NPT-MC simulations using this interaction potential predicted solubilities of RDX in CO₂ over a temperature range of 308 to 353 K and pressures ranging from 10.4 to 48.3 MPa that were in good agreement with experimental values.     

Directed synthesis of μ-1,3,5 bridged dicyanamides by thermal decomposition of μ-1,5 bridged precursor compounds

Reaction of transition-metal dicyanamides with pyridazine leads to the formation of the ligand-rich 1 : 2 (1 : 2 = ratio between metal salt and organic co-ligand) compounds [M(dca)(2)(pydz)(2)](n) (dca = dicyanamide, pydz = pyridazine) with M = Mn (1-Mn), Fe (1-Fe), Co (1-Co), Ni (1-Ni). In their crystal structures linear polymeric M-(dca)(2)-M chains are found, in which the M(ii) cations are μ-1,5 bridged by the dca anions. The pydz ligands are terminally N-bonded to the cations, which are octahedrally coordinated by two pydz ligands and four dca anions. On heating these precursor compounds, 1-Mn, 1-Fe and 1-Co transform quantitatively into new ligand-deficient 1 : 1 intermediate compounds of composition [M(dca)(2)(pydz)](n) with M = Mn (2-Mn), Fe (2-Fe) and Co (2-Co). Investigations by IR spectroscopy, and single crystal X-ray structure analysis, show that the intermediates form a more condensed layered structure in which half of the pristine μ-1,5 bridged dca anions become μ-1,3,5 bridging. This structural transformation is accompanied by a pronounced change of their magnetic properties: whereas the ligand-rich 1 : 2 compounds show only Curie-Weiss paramagnetism, the ligand-deficient 1 : 1 intermediates show either antiferro- or ferromagnetic ordering at lower temperatures mediated by the three-atom pathway of the μ-1,3,5 bridging dca anions.     

Synthesis and Crystal Structure of Diethyl (4,6-diamino-1,3,5-triazine-2-yl) phosphonate

1　INTRODUCTIONSomeoforganophosphoruscompounds,includingmanyheterocycliccompoundscontainingphosphonogroup,havegoodbioactivityinorganism[1].Duetotheirrela-tionwithbiochemical/biological,pharmacologicalandpesticidalresearch,hetero-cycliccompoundscontainingphosphonogrouphavebeensynthesizedbysomeofnewsyntheticmethods,inwhichseveralnewbuildingblockwereused,suchasβ-phos-phonicenemines,[2,3]isocyanomethylphosphonate,[4]β-functionalγ-oxo-alkylphos-phonates,[5]andacetylenicphosphonate.[6]Inourpr…