间二苄胍衍生物的合成

通过间二苄氯衍生物和二甲酰胺钠的亲核取代及水解方便地制备了相应的间二苄胺. 后者与甲基异硫脲作用生成间二苄胍硫酸盐,经离子交换得到相应的间二苄胍盐酸盐.     

Determination of amines as pentafluoropropionic acid anhydride derivatives in biological samples using liquid chromatography and tandem mass spectrometry

Determination of amines in biological samples as markers of exposure to the amines or the corresponding isocyanates is an important tool for industrial exposure assessment. In this study, a liquid chromatography and tandem mass spectrometry (LC-MS/MS) method for determination of amines in biological samples as perfluorofatty amides derivatives is presented. The method enables determination of diamines such as methylene diamine (MDA), toluene diamine (TDA), naphthalene diamine (NDA), hexamethylene diamine (HDA), isophorone diamine (IPDA), methylenedi(cyclohexylamine)(HMDA) and 4,4'-methylene-(2-chloroaniline)(MOCA) in human urine and plasma. The work-up procedure included hydrolysis of the biological samples with 3 M H(2)SO(4) at 100 degrees C for 16 h and extraction of the amines into toluene, where derivatisation of the amines with perfluorofatty acid anhydride was performed. Following removal of excess reagent and the acid formed and an exchange of solvent, the derivatives were analysed using gradient elution with an acetonitrile/water mobile phase composition and electrospray ionisation (ESI) with multiple reaction monitoring (MRM) of [M - H](-)-->[M - H - 120](-) or [119](-). Several perfluorofatty acid anhydrides were evaluated as derivatisation reagents, but the LC chromatographic properties of the pentafluoropropionic acid anhydride (PFPA) derivatives were favourable. Quantification of amine-PFPA derivatives was performed using deuterium labelled amine-PFPA derivatives as internals standards with good precision and linearity in the investigated range of 0-20 ng ml(-1) urine. The instrumental detection limits for the amine-PFPA derivatives were 0.2-3 fmol for MRM of [M - H](-)-->[119](-) and 0.3-8 fmol for [M - H](-)-->[M - H - 120](-). In 10 urine and 6 plasma samples from workers exposed to isocyanates, determination of TDA and MDA as PFPA derivatives was performed using LC-MS/MS and a reference GC-MS method. No significant difference between the two methods was observed.     

GENERAL APPROACH TO THE SYNTHESIS OF SYMMETRICAL 1,3,2-DIAZAPHOSPHOCANES

Abstract

Synthesis of eight-membered phosphorus-nitrogen heterocycles has been performed by phosphocyclization of the corresponding diamines using different derivatives of phos horous acid. The structures of diazaphosphocanes were supported by elemental analysis; ¹H, ¹³C, and ³¹PNMR spectroscopy; and x-ray diffraction analysis.     

Novel alicyclic dianhydrides and polyheterocycles on their basis

Dianhydrides of alicyclic tetracarboxylic acids were synthesized by chemical modification of tri-cyclodecenetetracarboxylic dianhydride and its chloro-containing derivatives. By polycondensation of these di-anhydrides with diamines polyimides were obtained. Thermal and thermooxidative degradation of these polyimides are discussed. By the interaction of polyamic acid carboxylic groups with diamines in presence of phosphorus pentoxide a number of polyimidoamidines have been synthesized, some physico-chemical properties of them are studied.     

α,β-Diketo nitriles as dielectrophiles. Formation of heterocyclic derivatives of amino acids

The reactions of mono Boc-protected amino monocarboxylic acids with phosphoranylideneacetonitrile yield ylido nitriles which on ozonolysis at low temperature form labile α,β-diketo nitriles. These derivatives may be used in situ for reaction with diamines or related dinucleophiles to yield hetero derivatives of interest as unnatural amino acid building blocks.     

Copolyamide-imides of controlled microstructure. Effect of reaction conditions on regularity and properties

Aromatic polyamide-imides, based on trimellitimide and 4,4′-diphenylmethane and with different degrees of order, have been obtained from symmetric and asymmetric monomers. The polymers have been prepared by two general methods: (1) low temperature solution polycondensation of diamines and carboxylic acid derivatives; and (2) high temperature solution polycondensation of diisocyanates and dicarboxylic acids. High field ¹H-NMR has been used to elucidate the chemical structures of monomers and polymers and to estimate quantitatively the degree of order and the distribution of head-to-head, tail-to-tail (amide-amide, imide-imide) and head-to-tail (amide-imide) units. The influences of microstructure and other molecular features on some properties of the polymers have also been investigated.     

Green synthesis of polycyclic benzimidazole derivatives and organic semiconductors

Polycyclic benzimidazole derivatives, an important class of compounds in organic electronics and photovoltaics, were prepared using a solvent-free "green" process based on heating carboxylic acid anhydrides and arylene diamines in the presence of zinc acetate in the solid state. Products were isolated and purified directly by train sublimation of the crude reaction mixtures. The reaction conditions were optimized using various carboxylic acid anhydrides. Optical and electrochemical properties of these materials are also described.     

Nanostructured diamine-fullerene derivatives: computational density functional theory study and experimental evidence for their formation via gas-phase functionalization

Nanostructure derivatives of fullerene C(60) are used in emerging applications of composite matrices, including protective and decorative coating, superadsorbent material, thin films, and lightweight high-strength fiber-reinforced materials, etc. In this study, quantum chemical calculations and experimental studies were performed to analyze the derivatives of diamine-fullerene prepared by the gas-phase solvent-free functionalization technique. In particular, the aliphatic 1,8-diamino-octane and the aromatic 1,5-diaminonaphthalene, which are diamines volatile in vacuum, were studied. We addressed two alternative mechanisms of the amination reaction via polyaddition and cross-linking of C(60) with diamines, using the pure GGA BLYP, PW91, and PBE functionals; further validation calculations were performed using the semiempirical dispersion GGA B97-D functional which contains parameters that have been specially adjusted by a more realistic view on dispersion contributions. In addition, we looked for experimental evidence for the covalent functionalization by using laser desorption/ionization time-of-flight mass spectrometry, thermogravimetric analysis, and atomic force microscopy.     

Synthesis of polyamides from diols and diamines with liberation of H2

The amidation reaction based on catalytic coupling of alcohols with amines previously reported by us, using the pincer complexes 1 and 2 as catalysts, was applied to the generation of polyamides from nonactivated diols and diamines. A range of polymers was prepared, with M_n up to 26.9 kDa. Unlike the traditional syntheses of polyamides based on carboxylic acid derivatives, which require the use of toxic reagents and generate stoichiometric amounts of waste, this process generates only molecular hydrogen as byproduct. Both aromatic and aliphatic diols and diamines were used. Gel permeation chromatography measurements of the dimethylformamide‐soluble polymers and thermal studies of the polyamides were performed. Matrix assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) spectra are also reported. Thermogravimetric analyses studies indicate that the aromatic polyamides (with the exception of the pyridine‐based polyamide) are more thermally stable than the aliphatic ones. This general, environmentally benign method for the synthesis of polyamides is homogeneously catalyzed under neutral conditions by dearomatized ruthenium‐pincer complexes 1 and 2 and proceeds in 1,4‐dioxane under an inert atmosphere. Conditions for polyamidation in the absence of solvent are also reported, using the pincer complex 2 as catalyst. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Trace analysis of airborne aromatic isocyanates and related aminoisocyanates and diamines using high-performance liquid chromatography with ultraviolet and electrochemical detection

A high-performance liquid chromatographic method was developed for trace analysis of complex air mixtures containing 2,6- and 2,4-toluenediisocyanates and related aminoisocyanates and diamines. The accuracy was tested at isocyanate concentrations of 2-1000 microg/m3 in air. The method is based on derivatization in the sampling step of isocyanate functions to corresponding urethane groups, with alkaline ethanol as the sampling and reacting medium. The derivatives formed, toluenediurethanes and tolueneaminourethanes, and unreacted diamines were detected by UV or electrochemically, the electrochemical detection being one order of magnitude more sensitive. Using an enrichment column, detection limits of ca. 0.05 pg/microl were obtained with electrochemical detection at a potential of 950 mV, which corresponds to air concentrations of 0.1 microg/m3 with 5 min sampling time at a rate of 11/min. The precision in the measurements were ca. 4% at concentrations of 6 microg/m3. A field measurement was performed concerning flame lamination of toluenediisocyanate-based polyurethane and cloth. Isocyanates, aminoisocyanates and diamines were found at air concentrations of 1-100 microg/m3.     

Synthesis of macrocyclic systems derived from di-(2-indolyl)heteroarenes

A number of new 3,6-di-(2-indolyl)-dibenzofuran and carbazole derivatives have been prepared from dibenzofuran and carbazole linkers via the Fischer indole synthesis. The bis-indoles were successfully formylated at C3 and the resulting dicarbaldehydes were combined with diamines to generate indole based imine macrocyclic systems.     

肽脱甲酰化酶抑制剂的合成及其抑菌活性

通过对肽脱甲酰化酶抑制剂构效关系的研究,以放线酰胺素为先导化合物,设计并合成了一系列异噁唑类化合物。其结构经1H NMR,IR,MS和元素分析表征。生物活性实验表明,该类化合物对标准肺炎克雷白球菌有显著的抑菌活性。     

Synthesis of 2‐(Quinoxalin‐2‐ylamino‐benzotriazolyl) Pentanedioic Derivatives as Potential Anti‐Folate Agents

Anti‐folate agents had a significant impact on therapeutic treatment plans for diseases such as cancer, and bacterial and parasitic infections, notably malaria. Quinoxaline derivatives showed in vitro anticancer activity and were able to inhibit both the dihydrofolate reductase and thymidylate synthase. Here, we decided to combine the chemical properties of quinoxalines and quinoxaline 1,4‐dioxides with those of benzotriazole nucleus with the aim to evaluate the resulting biological properties. Two main new series, including more than 60 compounds, were prepared. In the first one, the benzotriazole moiety was linked through the nitrogen atoms 1, 2, or 3, to a glutaric acid substituent to simulate a glutamic moiety. In the second series, the glutaric acid was substituted with acetic acid moiety to evaluate the effects of steric hindrance. Here, we describe the multistep chemical processes to obtain all titled quinoxalines starting from commercially available diamines. The classical oxidation of selected quinoxalines was unsuccessful, and we have come to an independent synthetic pathway to obtain new derivatives linked to the benzotriazole moieties starting from synthons bearing N‐oxide functionality.     

A Rapid HPLC Determination of C2–C7 Aliphatic Diamines by Precolumn Derivatization with Acetylacetone in Methanol-Water

A rapid reversed-phase high performance liquid chromatographic analysis for the determination of seven aliphatic diamines in water is described. Precolumn derivatization with acetylacetone is used for traces of aliphatic diamines in water-methanol (10:1 v/v) medium. The acetylacetone derivatives obtained after 15 min were extracted with an octadecylsilane functionalized silica cartridge, and then injected into the HPLC system. The HPLC system consisted of a reversed-phase column, and a spectrophotometric detector adjusted to 310 nm as elution solvent a methanol-tetrahydrofuran-water (55:3:42 v/v) mixture was used. The acetylacetone derivatives of the C2-C7 diamines were separated with a good resolution in 23 min. The detection limits achieved for each diamine were between 0.18-0.72 ng/ml for a 100 ml water sample. The recovery of diamine derivatives from river and seawater was 88-101%, with relative standard deviations of 2.2-4.0%, and 82-93%, with relative standard deviations of 2.8-4.6%, respectively. Aliphatic diamines are widely used as chemical reagents, occur as metabolic in biomedical studies and are used as chelating agents in analytical chemistry. As they are soluble in water, their use results in their ultimate release to the environment. The need for a sensitive, selective and rapid determination of aliphatic diamines in environmental samples thus has become important. Dobberpuhl et al. [1] have described a highly sensitive pulsed electrochemical detection for aliphatic monoamines and diamines following their chromatographic separation. Although, it is a sensitive method the determination has to be carried out in alkaline conditions. The most common method for the determination of aliphatic amines is high performance liquid chromatography (HPLC), using different derivatives with either fluorescence [2-5] or UV-visible detection [6-11]. The fluorescence detection method most often relies on post-column derivatization, which requires a second pump to deliver the reagent. Acetylacetone is soluble to some degree in water, and has been used as a pre-column derivatization reagent [12]. The reaction only is effective with diamines, and results in UV-active acetylacetone derivatives known as Schiff bases. But acetylacetone requires a long reaction time in water, which makes it rather unsuitable for routine analysis. In this paper an optimized reversed-phase HPLC determination procedure for C2-C7 aliphatic diamines at low ng/ml levels in water is described.     

Soluble polyimides containing alicyclic structures

A series of novel aromatic diamines containing kinked cycloalkane structures between two phenyl rings were synthesized by HCl-catalyzed condensation reaction of excess aniline and corresponding cycloalkanone derivatives. The structures of the diamines were indentified by ¹H NMR, ¹³C NMR, FT-IR spectroscopy and elemental analysis. The polyimides were synthesized from the obtained diamines with various aromatic dianhydrides by one-step polymerization in m-cresol. The polymerization was conducted for 6∼8 h with refluxing, which was enough to obtain the polymers with high molecular weight. The inherent viscosities of the resulting polyimides were in the range of 0.37∼1.66 dl/g. All polymers were readily soluble in common organic solvents such as chloroform, tetrachloroethane, dimethylacetamide, etc. and the glass transition temperatures were observed at 290 to 372°C. UV-visible spectra were obtained to measure the transparency of polymer films. Most of the polymers showed high transmission above 90 % in the wavelength of 450 ∼ 600 nm.     

Sidewall carboxylic acid functionalization of single-walled carbon nanotubes

The reactions of single-walled carbon nanotubes (SWNTs) with succinic or glutaric acid acyl peroxides in o-dichlorobenzene at 80-90 degrees C resulted in the addition of 2-carboxyethyl or 3-carboxypropyl groups, respectively, to the sidewalls of the SWNT. These acid-functionalized SWNTs were converted to acid chlorides by derivatization with SOCl(2) and then to amides with terminal diamines such as ethylenediamine, 4,4'-methylenebis(cyclohexylamine), and diethyltoluenediamine. The acid-functionalized SWNTs and the amide derivatives were characterized by a set of materials characterization methods including attenuated total reflectance (ATR) FTIR, Raman and solid state (13)C NMR spectroscopy, transmission electron microscopy (TEM), and thermal gravimetry-mass spectrometry (TG-MS). The degree of SWNT sidewall functionalization with the acid-terminated groups was estimated as 1 in 24 carbons on the basis of TG-MS data. In comparison with the pristine SWNTs, the acid-functionalized SWNTs show an improved solubility in polar solvents, for example, alcohols and water, which enables their processing for incorporation into polymer composite structures as well as for a variety of biomedical applications.     

Degradation of crosslinked unsaturated polyesters in sub-critical water

The degradation of unsaturated polyesters crosslinked with styrene was performed in sub-critical water (SCW) in the absence and presence of organic additives. The unsaturated polyesters were de-crosslinked by hydrolysis of ester chains to form polystyrene derivatives on SCW treatment at 300 °C. With an increase in treating time, carboxylic acid groups in the polystyrene derivatives were turned into carboxylic anhydride groups in SCW. The de-crosslinking rate was much enhanced on SCW treatment in the presence of hydroxy compounds with a long alkyl chain and alkylamines, while carboxylic acids, benzenesulfonate salts, and quaternary ammonium salts were ineffective even though they had a long alkyl chain. The degree of de-crosslinking was reduced in the presence of diamines and amino acids because re-crosslinking at both ends of the additive molecules proceeded.     

Organocatalytic Nucleophilic Addition of Hydrazones to Imines: Synthesis of Enantioenriched Vicinal Diamines

In the presence of a catalytic amount of chiral phosphoric acid, nucleophilic addition of N ‐monosubstituted hydrazones to N ‐Boc imines affords differentially protected vicinal diamines in the form of β‐amino N ,N ′‐dialkyldiazenes in excellent yields with high chemo‐, diastereo‐, and enantioselectivity. This catalytic asymmetric aza‐Mannich reaction represents the first example in which N ‐alkyl hydrazones serve as α‐azo carbanion equivalents to provide vicinal diamines with control of the two contiguous stereocenters. The adducts are readily converted into the monoprotected or free diamines and derivatives thereof.     

Synthetic studies on nucleoside-type muraymycins antibiotics based on the use of sulfur ylides. Synthesis of bioactive 5′-epimuraymycin analogues

A new synthetic approach to the 5-epimers of muraymycins, a family of complex nucleoside-type antibiotics, is reported based on the synthesis of epoxy amides obtained via the reaction of sulfur ylides with the uridyl aldehyde derivatives 16, 29 and 30, followed by a subsequent oxirane ring opening reaction with diamines. This new strategy offers an excellent opportunity for the preparation of muraymycin analogues of biological interest. In fact, biological studies have revealed these 5′-epimers to be as biologically potent as the natural antibiotics, aside of representing a convergent and flexible route towards the natural congeners.     

Synthesis of diacetylamino and diamino derivatives of adamantane series

1,3-Diacetylamino derivatives were synthesized directly from adamantane series hydrocarbons or from adamantan-1-ylacetic acids by a one-pot method with a succession of an oxidation stage and Ritter’s reaction in nitric acid and in a mixture of sulfuric and nitric acids. The hydrolysis of 1,3-diacetylamino derivatives in an acidic medium leads to scaffold diamines and diaminoacids.