Study on Ionic Organotin Compounds Ⅲ. Synthesis of Five-Coordinated Anionic Tin(Ⅳ) Complexes and Crystal Structure of [ ( i-Pr)2NH2] [ PhSn(μ2-SCH2COO)2]

The study of ionic organotin compounds is of current attention owing to their diversified molecular structures and wide range of applications, such as biological activities[1 ～3] and as catalysts in organic synthesis. [4] Recently, we synthesized some new ionic organotin compounds by dephenylation reaction. [5] In this paper, we continued to study the reaction of mercaptoacetic acid with phenyltin trichloride in the presence of organic base. The reaction equation was as follows:     

Thermokinetics on the reaction of formation of Dy[(C_5H_8NS_2)_3(C_(12)H_8N_2)]

The enthalpy change of formation of the reaction of hydrous dysprosium chloride with ammonium pyrrolidinedithiocarbamate (APDC) and 1,10-phenanthroline (o-phen·H2O) in absolute ethanol at 298.15 K has been determined as (-16.12±0.05) kJ·mol-1 by a microcalor-meter. Thermodynamic parameters (the activation enthalpy, the activation entropy and the activation free energy), rate constant and kinetics parameters (the apparent activation energy, the pre-exponential constant and the reaction order) of the reaction have also been calculated. The enthalpy change of the solid-phase reaction at 298.15 K has been obtained as (53.59±0.29) kJ·mol-1 by a thermochemistry cycle. The values of the enthalpy change of formation both in liquid-phase and solid-phase reaction indicated that the complex could only be synthesized in liquid-phase reaction.     

AN EASY ROUTE TO SYNTHESIZE COPPER(I) COMPLEXES Cu_2(Ph_2PCH_2PPh_2)_2(NO_a)_2 AND Cu(Ph_2PCH_2CH_2PPh_2)(NO_a). THEIR CHARACTERIZATION AND ELECTROCHEMISTRY

Binuclear Cu(Ⅰ) complex [Cu(dppm)(NO_3)]2 (dppm=Ph_2PCH_2PPh_2) and mononuclear Cu(Ⅰ) complex [Cu(dppe)(NO_3)] (dppe=Ph_2PCH_2CH_2PPh_2) have been synthesized by the ligand-reduction reaction of cupric nitrate with dppm and dppe in methanol and characterized by means of ICP, elemental analyses, molecular weight determination, TG, ~(31)P-NMR, IR and Raman spectra; their electronic conductivities and CV waves have also been measured. Results show that dppm coordinates to the Cu(Ⅰ) atoms as a bridging bidentate ligand and dppe as a chelating bidentate ligand, (NO_3)~(-1) behaves as a chelating bidentate ligand in both of the newly prepared complexes.     

Crystal Structure of Ethoxyethyl 3-(2-Chloro-5-pyridyl methylamino)-2-cyano-4-methylpent-2-enoate

1 INTRODUCTION The nature and topography of the herbicide binding site in the reaction center of photosystem Ⅱ (PSⅡ) have been the subject of intense interest for many years. Among several commercially important herbicides with different structures such as atrazine and polypeptide of the PSII reaction center[1], the cyanoacrylates with general structure 1 have proved hightly potent and useful as probes[2, 3] of the receptor because their activities as inhibitors of photosynthetic ele…     

A domino desulfitative coupling and decarboxylative coupling of 3,4-dihydropyrimidine-2-thiones with copper(Ⅰ) carboxylates

A novel and general carbon-nitrogen and carbon-carbon cross-coupling reaction between 3,4-dihydropyrimidine-2-thiones and copper(Ⅰ) carboxylates were performed in the presence of palladium acetate.The copper(Ⅰ) carboxylates act not only as desulfurative reagents but also as sources of carbon nudeophiles.A wide array of highly substituted and functionalized pyrimidines scaffolds were synthesized in good yields.     

[(NHC)CrCl(μ-Cl)(THF)]_2 and(NHC)_2CrCl_2(NHC=1,3-Diisopropyl-4,5-dimethylimidazole-2-ylidene):Syntheses,Structures,and Polymerization Activities

The preparation of divalent chromium N-heterocyclic carbene(NHC,1,3-diisopropyl4,5-dimethylimidazole-2-ylidene) compounds is reported.The reaction of 1:1 molar ratio of NHC with CrCl2 led to an isolation of [(NHC)CrCl(μ-Cl)(THF)]2(1),while that of 2:1 ratio resulted in the formation of(NHC)2CrCl2(2).1 can be considered as an intermediate in the formation of 2 and further converted into 2 by the addition of another equiv.of NHC.The reaction of 2 with CpNa afforded an ion pair compound [(NHC)2CrCp]+[Cp]-(3),indicating a strong coordination ability of NHC supplanting one of the ionic Cr-Cp bonding.In combination of methylalumoxane(MAO) as cocatalyst 1 and 2 both are active for catalyzing ethylene polymerization.     

Tin(II) Chloride Dihydrate Catalyzed Groebke Condensation: An Efficient Protocol for the Synthesis of 3-Aminoimidazo[1,2-a]pyridines

The ability of tin(II) chloride dihydrate as a catalyst to promote the three-component condensation reaction from a diversity of aromatic aldehydes, 2-aminopyridines and isonitriles at room temperature is described. This methodology affords a number of 3-aminoimidazo[1,2-a]pyridines in the presence of tin(II) chloride dihydrate as a new and mild Lewis acid catalyst in the multi-component reaction in reasonable yields and short reaction time without any significant optimization of the reaction conditions.     

Studies on New Additions to 5-Methoxy-2 (5H)-Furanone: 1, 4-Addition of Grignard Reagents, and 1,3-Dipolar Cycloaddition of Silyl Nitronates

Recently, much effort has been made in the development of generally applicable organic synthesis of 5-alkyloxy-2(5H)-furanones due to their essential structure entities in the synthesis of some biologically active natural products and their application as useful intermediates in organic synthesis1. Their reactions such as Michael addition, Diels-Alder reaction and photocatalyzed conjugate addition have been studied extensively2-4.However, Michael addition reaction of Grignard reagents to 5-m…     

Bismuth Mediated Organic Reaction: A Convenient Method for the Synthesis of Allylic (Benzylic) Selenides and α-Organylselenocarbonyl Compounds in Aqueous Media

Organic reactions promoted by active metals have aroused much interest in recent years. Active bismuth has been used in Barbier-type reaction of allylic halides with aldehydes1 and aldimines2 as well as Reformatzky type reaction3. Other publications referred to the cross coupling between aldehydes and α-diketones4, the substitution to benzotriazole drivatives5 and the reductive coupling reaction of nitro compounds6. These reactions generally promoted by elemental bismuth generated in situ fr…     

PhI(OAc)_2-promoted umpolung acetoxylation of enamides for the synthesis of α-acetoxy ketones

Umpolung is a fundamental concept in organic chemistry, which provides an alternative strategy for the synthesis of target compounds which were not easily accessible by conventional methods. Herein, a mild and efficient PhI(OAc)_2-promoted umpolung acetoxylation reactions of enamides was developed for the synthesis of α-acetoxy ketones. The reaction tolerates a wide range of functional groups and affords α-acetoxy ketones in good to excellent yields. PhI(OAc)_2 serves as a source of acetoxy in the reaction.     

Greener approach toward synthesis of biologically active s-Triazine (TCT) derivatives: A recent update

The greener methodology to synthesize s-triazine derivatives (also known as TCT) is described, including synthesis through microwave, ultrasound, and solvent-free conditions. This review mainly focuses on reactions of TCT (2,4,6-trichloro-1,3,5-triazine) with various substituents having amine and hydroxy functionalities to give corresponding triazine derivatives under a greener approach. The results of reactions indicate that, unlike classical methods, green methods result in better yields of the product, through a rapid reaction, under mild reaction conditions, and by easy workup procedures.     

Mild,efficient Fischer indole synthesis using 2,4,6-trichloro-1,3,5-triazine (TCT)

Mild and efficient protocol for the Fischer indole synthesis using TCT has been described. TCT serves as a mild and inexpensive catalyst. Under these conditions several functional groups such as ester, cyano, sulfone, amides, and ethers are tolerated. By this method, many functionalized analytically pure indoles were prepared easily without the need of purification.     

Wet 2,4,6-trichloro-1,3,5-triazine(TCT)as an efficient catalyst for the synthesis of 2,4,6-triarylpyridines under solvent-free conditions

<正>An efficient one-pot synthesis of 2,4,6-triarylpyridines has been described.This involves the three-component reaction of aldehydes,ketones and ammonium acetate in the presence of a catalytic amount of wet 2,4,6-trichloro-1,3,5-triazine(TCT) under solvent-free condition at 130℃.     

Chemical reduction of 2,4,6-tricyano-1,3,5-triazine and 1,3,5-tricyanobenzene. Formation of novel 4,4',6,6'-Tetracyano-2,2'-bitriazine and its radical anion

Chemical reduction of 2,4,6-tricyano-1,3,5-triazine, TCT, results in the formation of an unstable radical anion that undergoes immediate dimerization at a ring carbon to form [C(12)N(12)](2-), [TCT](2)(2-), characterized by a long 1.570 (4) A central C[bond]C. [TCT](2)(2-) can decompose into the radical anion of 4,4',6,6'-tetracyano-2,2'-bitriazine, [TCBT]*-, the one-electron reduced form of planar (D(2h)) TCBT, which is also structurally characterized as the [TMPD][TCBT] charge-transfer complex (TMPD = N,N,N',N'-tetramethyl-p-phenylenediamine) with a 1.492 (2) A central sp(2)[bond]sp(2) C[bond]C. Although crystals could not be obtained for the radical anion [TCBT]*-, the electrochemistry (E degrees = +0.03 V), EPR (g = 2.003, (2)A((14)N) = 3.347 G, and (4)A((14)N) = 0.765 G and a line width of 0.24 G), and theoretical calculations support the formation of [TCBT]*-. In addition, thermolysis of [TCT](2)(2-) yields [TCBT]*-. Chemical reduction of 2,4,6-tricyanobenzene, TCB, forms an unstable radical anion that immediately undergoes dimerization at a ring carbon to form [C(12)H(6)N(6)](2-), [TCB](2)(2-), which has a long 1.560 (5) A central C[bond]C. Reaction of TCT with tetrathiafulvalene (TTF) forms structurally characterized [TTF][TCT], and in the presence of water, TCT hydrolyzes to 2,4-dicyano-6-hydroxy-s-triazine, DCTOH. In contrast, the reaction of TCT with TMPD forms [TMPD][TCT], which in the presence of water forms structurally characterized [HTMPD](+)[DCTO](-).     

2,4,6-Trichloro-1,3,5-triazine (TCT) mediated one-pot sequential functionalisation of glycosides for the generation of orthogonally protected monosaccharide building blocks

Orthogonally protected monosaccharide building blocks have been prepared using TCT in a one-pot multicomponent transformation. The process involves successive steps of arylidene acetalation, esterification and regioselective reductive acetal cleavage. High regioselectivity, scope for using a broad range of substrates, functional group tolerance, mild reaction conditions, easy handling process and wide application range are a few advantages of the current process.     

A mild and general method for preparation of α-glycosyl chlorides

A mild and efficient chlorination method for production of glycosyl chlorides is first described which employs inexpensive trichlorotriazine (TCT) and DMF as a chlorination reagent and is compatible with typical acid-labile hydroxyl protecting functions. The scope and limitations, reaction mechanism and its application in the sequential glycosylations are discussed.     

Nickel-catalysed CO bond reduction of 2,4,6-triaryloxy-1,3,5-triazines in 2-methyltetrahydrofuran

A nickel-catalysed reduction of phenol derivatives activated by 2,4,6-trichloro-1,3,5-triazine (TCT) in ecofriendly 2-methyltetrahydrofuran (2-MeTHF) was described.     

Bioanalytical Method Development and Validation Study of Neuroprotective Extract of Kashmiri Saffron Using Ultra-Fast Liquid Chromatography-Tandem Mass Spectrometry (UFLC-MS/MS): In Vivo Pharmacokinetics of Apocarotenoids and Carotenoids

Kashmir saffron (Crocus sativus L.), also known as Indian saffron, is an important Asian medicinal plant with protective therapeutic applications in brain health. The main bioactive in Kashmir or Indian Saffron (KCS) and its extract (CSE) are apocarotenoids picrocrocin (PIC) and safranal (SAF) with carotenoids, crocetin esters (crocins), and crocetins. The ultra-fast liquid chromatography(UFLC)- photodiode array standardization confirmed the presence of biomarkers PIC, trans-4-GG-crocin (T4C), trans-3-Gg-crocin (T3C), cis-4-GG-crocin (C4C), trans-2-gg-crocin (T2C), trans-crocetin (TCT), and SAF in CSE. This study’s objectives were to develop and validate a sensitive and rapid UFLC-tandem mass spectrometry method for PIC and SAF along T4C and TCT in rat plasma with internal standards (IS). The calibration curves were linear (R² > 0.990), with the lower limit of quantification (LLOQ) as 10 ng/mL. The UFLC-MS/MS assay-based precision (RSD, <15%) and accuracy (RE, −11.03–9.96) on analytical quality control (QC) levels were well within the acceptance criteria with excellent recoveries (91.18–106.86%) in plasma samples. The method was applied to investigate the in vivo pharmacokinetic parameters after oral administration of 40 mg/kg CSE in the rats (n = 6). The active metabolite TCT and T4C, PIC, SAF were quantified for the first time with T3C, C4C, T2C by this validated bioanalytical method, which will be useful for preclinical/clinical trials of CSE as a potential neuroprotective dietary supplement.     

Use of 2,4,6-trichloro-1,3,5-triazine (TCT) as organic catalyst in organic synthesis

Organic catalysts have found wide applications in organic synthesis. Many organic reactions, which originally do not occur under normal conditions or are difficult to operate normally, have been successfully conducted under mild conditions in the presence of catalysts. In recent years, 2,4,6-trichloro-1,3,5-triazine (TCT, cyanuric chloride) has been used as organic catalyst in many organic synthesis, because it is stable, nonvolatile, inexpensive, commercially available, and easy to handle. On account of these properties it has been used as a green catalyst and sometimes is a catalyst of choice in organic reactions.     

液相色谱-串联质谱法测定百日咳和百白破疫苗中百日咳杆菌气管细胞毒素

百日咳杆菌气管细胞毒素（TCT）是一种引起百日咳及百日咳相关疫苗不良反应的毒性糖肽。尽管各国药典均规定了百日咳疫苗产品中TCT的含量限度，但均没有推荐TCT的含量测定方法。该研究发展了一种液相色谱-串联质谱法用于TCT的含量测定。实验优化了包括色谱柱类型和流动相组成在内的TCT色谱条件。虽然TCT在反相色谱模式和亲水作用色谱（HILIC）模式下均具有较好的保留，但HILIC模式与蛋白质沉淀的前处理方法兼容性更好，因此采用HILIC模式分离TCT。优化所得的方法具有较宽的线性范围（5.76~369 ng/L），良好的重复性（峰面积的相对标准偏差不大于3.9%），各种基质中均有较好的回收率（96.4%~102.5%），且定量限是药典要求的TCT最高限量的1/1279。将本方法用于共纯化百日咳疫苗、组分百日咳疫苗、共纯化无细胞百白破疫苗和组分无细胞百白破疫苗中TCT的检测，所有产品均未检出TCT，表明被检样品具有较好的工艺条件可避免TCT在产品中的残留。