Amines release from schiff bases polymers and diffusion from dosage forms with eudragit RL in acidic medium

Chloromethylstyrene 1 (mixture meta and para; 60/40) can be oxydized in corresponding aldehyde 2 . Vinylbenzaldehyde 2 reacts with primary amines such as aniline, benzylamine, 2-phenylethylamine, 3-phenylpropylamine, and 2-aminopyridin to give Schiff bases that are polymerized in bulk with a radical initiator. Poly(vinyl benzaldehyde) 6 prepared from corresponding monomer 2 also reacts with primary amines to give polymeric Schiff bases. Hydrolyses of these polymeric imines have been carried out either in heterogeneous acidic medium or basic heterogeneous medium; a suitable percentage of amines has been released after some hours. Finally, a study of hydrolysis and of diffusion of released amines in a dosage form (Eudragit RL) has been also carried out with some polymeric Schiff bases.     

Jensenone: Biological Reactivity of a Marsupial Antifeedant from Eucalyptus

The resistance of Eucalyptus to browsing mammals has been related to the level and type of formylated phloroglucinol compounds (FPCs) present in the leaf. The antifeedant activity of FPCs appears to depend on their aldehyde groups, but little else is known of their mode of action. We have sought to elucidate this further by examining the biological reactivity and disposition of jensenone, a model FPC. Neither jensenone nor any metabolites were detected in urine or feces of marsupial brushtail or ringtail possums that had ingested up to 725 mg x kg(-0.75). When jensenone was incubated in rat gastrointestinal segments in vitro, it rapidly disappeared. Jensenone also reacted rapidly with glutathione, cysteine, glycine, ethanolamine, and trypsin, and more slowly with acetylcysteine and albumin. Sideroxylonal, a more complex FPC, exhibited the same reactivity. Torquatone, a related compound that lacks both aldehyde groups and antifeedant activity, was unreactive. Mass spectroscopic analysis indicated that the adducts were Schiff bases formed between the aldehyde groups of FPCs and amine groups of the conjugating molecules. Successive adducts were formed with the two aldehyde groups of jensenone, and the four groups of sideroxylonal. The jensenone bis-glutathione adduct appeared to cyclize to the disulfide form. These findings suggest that the antifeedant effects of FPCs are due to their facile binding to amine groups on critical molecules in the gastrointestinal tract, leading to a loss of metabolic function. The consequent toxic reaction, probably involving chemical mediators such as 5-hydroxytryptamine (5HT), may cause colic, nausea, and a general malaise, resulting in anorexia.     

Modulation of the Selectivity of Schiff Base Formation in Mixtures of Two NH2 Compounds and One Aldehyde or of Two Aldehydes and One Amine

Mixtures containing two NH₂ compounds and one aldehyde, or two aldehydes and one amine, are investigated. In particular, the selectivity of the process of Schiff base formation is explored, as well as additives (acid, metal ions) that can modulate this selectivity.     

Schiff bases and their complexes: Recent progress in thermal analysis

Schiff bases are versatile compounds synthesized from the condensation of primary amino compounds with aldehydes or ketones. The high thermal of many Schiff base and their complexes were useful attributes for their application as catalysts in reactions involving at high temperatures. This thermal behavior of Schiff bases and their complexes was evaluated by TGA/DTG and DTA curves with mass losses related to dehydration and decomposition. This review summarizes the developments in the last decade for thermal analysis of Schiff bases. Therefore, synthesis of Schiff bases and their complexes are reviewed.     

Amino-formaldehyde resins. Analysis by application of a mannich type reaction

The formation of Mannich bases from secondary aliphatic amines and primary alkoxymethyl compounds of urea and melamine in basic media have been studied. The rate of formation of the Mannich base is equal to the rate of decomposition of the alkoxymethyl compound. This is explained by a reaction of the amine with the Schiff base, the intermediate formed during the alkoxymethyl decomposition. In a mixture of primary alkoxymethyl and hydroxymethyl compounds of urea and melamine, the amine reacts almost selectively with the alkoxymethyl compound. An analytical method for the determination of primary dimethylene ether groups of primary alkoxymethyl groups in mixture with hydroxymethyl groups is developed.     

The yellowing mechanism of polyesteramide based on poly(ethylene terephthalate) and polyamide 6

The yellowing mechanism in polyesteramide based on poly(ethylene terephthalate) and polyamide 6 (PET-PA6) has been studied. Amine model compounds were employed to react with acetaldehyde (AA), and 1H-nuclear magnetic resonance spectrometer (¹H-NMR), fourier transform infrared spectroscopy (FT-IR), and electrospray ionization mass spectrometry (ESI-MS) were used to characterize the structure of the yellowing products. ¹³C-NMR, laser confocal micro-Raman spectrum, and X-ray photoelectron spectroscopy (XPS) were used to characterize the yellowing products of the reaction of PA6 oligomers and AA. The structures of yellowing substances in the two systems are consistent. The color generation is mainly caused by the reaction of the terminal primary amine group of PA6 with AA, which is the thermal degradation product of PET, to form Schiff bases. These Schiff bases condense further to form a conjugated imine structure, which may be the main chromophore of polyesteramide. Due to the degradation of PA6 segments of the copolymer, it may further degrade to form new primary amino groups and increase yellowness during use.     

Preparation of schiff base adducts of phosphatidylcholine core aldehydes and aminophospholipids, amino acids, and myoglobin

We have prepared Schiff base adducts of the core aldehydes of phosphatidylcholine and aminophospholipids, free amino acids, and myoglobin. The Schiff bases of the ethanolamine and serine glycerophospholipids were obtained by reacting sn-1-palmitoyl(stearoyl)-2-[9-oxo]nonanoyl-glycerophosphocholine (PC-Ald) with a twofold excess of the aminophospholipid in chloroform/methanol 2∶1 (vol/vol) for 18 h at room temperature. The Schiff bases of the amino acids and myoglobin were obtained by reacting the aldehyde with an excess of isoleucine, valine, lysine, methyl ester lysine and myoglobin in aqueous methanol for 18 h at room temperature. Prior to isolation, the Schiff bases were reduced with sodium cyanoborohydride in methanol for 30 min at 4°C. The reaction products were characterized by normal-phase high-performance liquid chromatography and on-line mass spectrometry with electrospray ionization. The amino acids and aminophospholipids yielded single adducts. A double adduct was obtained for myoglobin, which theoretically could have accepted up to 23 PC-Ald groups. The yields of the products ranged from 12 to 44% for the aminophospholipids and from 15–57% for the amino acids, while the Schiff base of the myoglobin was estimated at 5% level. The new compounds are used as reference standards for the detection of high molecular weight Schiff bases in lipid extracts of natural products. Based on presentation at the AOCS Annual Meeting & Expo in Indianapolis, Indiana, April 28–May 1, 1996.     

Novel Poly(Styrene) Attached Schiff Bases for Uptake Mn(II) and Ni(II) Ions and as Antimicrobial Agent against Micrococcus luteus

In this study, three novel poly(styrene) attached Schiff bases (AMP–SB) were synthesized from condensation reaction of (aminomethyl)polystyrene with 2-hydroxy-5-bromobenzaldehyde, 2-hydroxy-5-methylbenzaldehyde and 2-hydroxy-5-chlorobenzaldehyde for uptake from solutions containing Mn(II) and Ni(II) ions and as antimicrobial agent against Micrococcus luteus. Furthermore coordination polymers were synthesized including Mn(II) and Ni(II) ions for understand to geometric structure of uptake ions. Polymers attached Schiff bases and coordination polymers were characterized by means of elemental analyses, magnetic measurements, FTIR, UV-GB, TG/DTA and ¹H-NMR. The Ni(II) and Mn(II) contents in the metal-containing polymer complexes were determined by the ICP-MS technique. Antibacterial activities of the polymers attached Schiff bases and their complexes were studied by the well-diffusion method against M. luteus (ATCC-9341).     

3-氨基-5-羧基-1,2,4-三唑席夫碱的合成

含1,2,4-三唑环的席夫碱化合物一般都具有很好的生物活性。为了进一步探讨1,2,4-三唑席夫碱的合成,文中以3-氨基-5-羧基-1,2,4-三唑为原料,与取代芳醛反应,合成了8个3-氨基-5-羧基-1,2,4-三唑类席夫碱化合物。采用的反应条件为:3-氨基-5羧基-1,2,4-三唑与取代芳醛的摩尔比为1∶1,N,N-二甲基甲酰胺(DMF)为溶剂,冰醋酸为催化剂,在回流温度下反应3.5—4.5 h。化合物的结构通过IR,1H NMR和元素分析进行了表征。样品分析结果表明,在红外光谱中,所得目标产物在波数ν=1 600—1 625 cm-1处均出现C N的特征吸收峰;在1H核磁共振中,化学位移δ9附近有CH N的质子的化学位移出现。     

Some Schiff Base Surfactants as Steel-Corrosion Inhibitors

Two series of Schiff base amphiphiles were prepared by condensation of benzaldehyde or anisaldehyde with three different alkyl chain length fatty amines namely: dodecyl, hexadecyl and octadecyl amine. The chemical structures of the prepared Schiff bases were confirmed by using different techniques, (elemental analysis, FTIR and ¹H-NMR spectra). The data of structural analysis for these compounds were confirmed by the purity of the synthesized amphiphiles. The synthesized Schiff bases were evaluated as corrosion inhibitors for low carbon steel (mild steel) in various acidic media (HCl and H₂SO₄) using a weight loss technique. The corrosion inhibition measurements of these inhibitors showed high protection against corrosion process in the tested acidic media at different doses (50, 100, 150 and 200 ppm) as well as their having a good biocidal effect against sulphate reducing bacteria. The discussion correlated the efficient corrosion inhibition of these inhibitors to their chemical structures.     

室温固相研磨法合成邻氨基苯甲酸类芳醛席夫碱的研究

为了寻找清洁而方便的有机席夫碱制备方法,我们以邻氨基苯甲酸和各种芳醛的物质的量之比为1∶1的比例,采用室温固相研磨合成法,在常温下合成了10种邻氨基苯甲酸类芳醛席夫碱化合物,反应几乎定量完成。用熔点测定和元素分析法对其进行表征。重结晶产率达70%～82%,该法具有反应条件温和,反应时间短,产率高和分离提纯容易等特点,是实验室合成邻氨基苯甲酸类席夫碱的一种快捷而实用的方法。     

丹皮酚缩脂肪胺Schiff碱的合成及生物活性研究

以丹皮酚和脂肪胺为主要原料,合成9种Schiff碱化合物,并对标题化合物进行表征。利用细菌作为生物指示,采用琼脂扩散法测定了目标产物的抑菌性能;通过DPPH.分析法,测定了目标产物的抗氧化性。结果表明:目标产物对所受试菌种都有一定的抑制作用,但其清除自由基能力比较弱。     

两种含二茂铁基schiff 碱的合成及其抑菌活性

通过乙酰基二茂铁与两种杂环胺(4-氨基安替比林,2-氨基-5-巯基-1,3,4-噻二唑)缩合合成了两种含二茂铁基的Schiff碱(a、b),产率分别为85.8%和72.6%,并通过IR、1HNMR及元素分析对其结构进行了确证。最后,将合成出的两种Schiff碱分别对3种细菌(金黄色葡萄球菌、大肠杆菌、枯草芽孢杆菌)进行了初步抑菌实验,将其结果与非杂环类Schiff碱Fc-C(CH3)NC6H5=(c)的抑菌性能做了比较。结果表明,Schiff碱对上述3种细菌都有抑制作用,且抑菌效果随着Schiff碱浓度的增大而增强。此外,杂环类Schiff碱(a、b)对上述3种细菌的抑菌活性明显优于非杂环类Schiff碱(c)。     

俄罗斯脂肪胺生产及欧洲织物柔软剂应用进展

综述了俄罗斯脂肪胺生产技术,醛还原烷基化制伯胺,伯胺甲醛甲基化制叔胺及伯胺乙氧基化季铵化制乙氧基季铵盐。欧洲生产的乙氧基化季铵盐,咪唑啉阳离子ＳＡＡ及其在织物柔软剂上的应用进展,对国内叔胺生产工艺路线的选择和织物柔软剂开发品种提出了可行性建议。     

4-氨基-1,2,4-三氮唑并芳香醛类希夫碱的合成与表征

三氮唑环为抗真菌药物的基本药效基团,为探索芳香醛缩氨基三氮唑的合成条件,以4-氨基-1,2,4-三氮唑与芳香醛为原料,在冰醋酸催化下合成了9种芳香醛类希夫碱,收率71.6%~92.3%,并通过元素分析、IR和1H NMR确定了目标化合物的结构。其中几种鲜见文献报道。同时讨论了影响反应收率的因素。     

Synthesis and Characterization of Thermally Stable and Biologically Active Metal-Based Schiff Base Polymer

Schiff base was prepared via condensation of ethanedihydrazide with 2-hydroxy benzaldehyde and further this monomeric Schiff base polymerize with formaldehyde and barbituric acid and form polymeric Schiff base (PLSB) ligand. The ligand and its polymer metal complexes were characterized by using elemental analysis, IR, UV–VIS, ¹HNMR, magnetic susceptibility and thermogravimetric studies. On basis of elemental analysis and spectral studies, six coordinated geometry was assigned for Mn(II), Co(II) and Ni(II) complexes and four coordinated for Cu(II) and Zn(II) complexes. PLSB act as a tetradentate and coordinate through the azomethine nitrogen and phenolic oxygen. The thermal behavior of these polymer metal complexes showed that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The (PLSB) ligands and its polymer metal complexes were screened against bacterial species Escherichia coli, Staphylococcus aureus, Bacillus subtilis and fungal species Aspergillus flavus, Candida albicans, A. niger. The activity data show that the metal complexes were more potent than the parent Schiff bases.     

Microwave synthesis and spectroscopic studies of some complex compounds as pigments and their applications in paints

Metal complex pigments have been widely used for various applications such as pigments in coatings. This work presents the use of microwave technique (Green chemistry) for the synthesis of new copper(II), nickel(II), iron(III), and chromium(III) Schiff base complexes derived from metal salts and Schiff base ligand. Also, the microwave technique was used in the synthesis of Schiff base ligand which is derived from selected amine, namely methoxy-tolidine, and selected aldehyde, namely 2-hydroxynaphthaldehyde. The prepared ligand and metal complex pigments were characterized by elemental analysis, NMR, spectral UV–Vis, infrared, and thermal gravimetric analysis. The physical and mechanical properties and corrosion resistance of dry paint films were also examined. The obtained results revealed that the prepared metal complex pigments showed excellent mechanical and corrosion resistance.     

双水杨醛缩对苯二胺、双水杨醛缩4,4′-联苯二胺的合成与表征

以水杨醛、胺类为原料,经缩合反应,合成了2种水杨醛类席夫碱化合物双水杨醛缩对苯二胺、双水杨醛缩4,4′-联苯二胺,利用元素分析、红外光谱对其结构进行了确认,并对其荧光发光性能作了初步研究.     

含二茂铁基Schiff碱型配体的合成研究

二茂铁甲醛与胺在无水乙醇中缩合成了10个新型Schiff碱，通过元素分析，红外光谱和紫外光谱确证了其结构。     

酚醛胺/环氧树脂胶粘剂耐化学介质性能研究

以自制酚醛胺作为环氧树脂(EP)的固化剂,研究了酚醛胺/EP胶粘剂的耐化学介质性能和耐久性。结果表明:酚醛胺/EP胶粘剂在水、10%NaOH和2%NaCl溶液中浸泡48 h时,其剪切强度分别为6.61、4.66、5.12 MPa,其强度保留率分别为87.90%、61.97%、68.09%;酚醛胺/EP胶粘剂既具有良好的耐水性、耐碱性和耐盐性,又具有较好的碱、盐耐久性,可作为特种胶粘剂——水下胶粘剂广泛用于房屋、水利、地下建筑、医疗、仿生和养殖等领域,并具有良好的经济效益和应用前景。