Synthesis of some mixed esters of thiophosphoric acid

Summary Six esters of O,O-dialkyl S-carbalkoxymethylphosphinic acids that have not been described in the literature were prepared and their structures demonstrated.     

Synthesis and structure of amino esters of menthol

The conditions for the acylation of (?)-menthol with monochloroacetyl chloride have been studied. Amino esters of (?)-menthol have been obtained by the nucleophilic replacement of the chlorine in (?)-menthol monochloroacetate by residues of secondary amines. Their properties and their mass, IR, and¹³C NMR spectra are described.     

Novel Methods for the Synthesis of Phosphonate Esters on the Solid Surface

Phosphonate esters are versatile intermediate in organic synthesis. These compounds have found a wide range of application in the areas of industrial, agricultural, and medicinal chemistry owing to their physical properties as well as their utility as synthesis intermediates. The synthesis of some phosphonate esters under solvent free condition was described. These methods are easy, rapid, and high-yielding reactions for the synthesis of phosphonate esters.     

Characterization of fatty acid esters of okadaic acid and related toxins in blue mussels (Mytilus edulis) from Norway

Marine algal toxins of the okadaic acid group can occur as fatty acid esters in blue mussels, and are commonly determined indirectly by transformation to their parent toxins by alkaline hydrolysis. Some data are available regarding the identity of the fatty acid esters, mainly of palmitic acid (16:0) derivatives of okadaic acid (OA), dinophysistoxin-1 (DTX1) and dinophysistoxin-2 (DTX2). Other fatty acid derivatives have been described, but with limited mass spectral data. In this paper, the mass spectral characterization of the [M-H](-) and [M+Na](+) ions of 16 fatty acid derivatives of each of OA, DTX1 and DTX2 is presented. The characteristic fragmentation of [M+Na](+) ions of OA analogues provided a useful tool for identifying these, and has not been described previously. In addition, a set of negative ion multiple reaction monitoring (MRM) methods was developed for direct determination of 16 fatty acid esters of OA, 16 fatty acid esters of DTX1 and 16 fatty acid esters of DTX2 in shellfish extracts. The MRM methods were employed to study the profiles of fatty acid esters of OA analogues in blue mussels and to compare these with fatty acid ester profiles reported for other groups of marine algal toxins.     

Mass spectra of piperidine dicarboxylic acids and their esters

Electron impact mass spectra of the epimers of 2,4-, 2,5-, and 2,6-piperidine dicarboxylic acids and their methyl esters and N-acyl derivatives have been studied. Data from DADI spectra have been used to establish the basic fragmentation paths. Chemical ionization spectra of positive and negative ions of 2,4- and 2,5-piperidine dicarboxylic acids are described.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1490–1495, November, 1986.     

Highly enantioselective synthesis of tertiary boronic esters and their stereospecific conversion to other functional groups and quaternary stereocentres

Organoboron compounds are useful in asymmetric synthesis. We have developed an efficient methodology for the highly enantioselective synthesis of tertiary boronic esters from the corresponding secondary benzylic alcohols. Further stereospecific transformations of the boronic ester moiety are described including the preparation of tertiary alcohols, C-tertiary amines and tertiary arylalkanes. Several homologations of tertiary boronic esters have also been developed for the construction of quaternary stereocentres.     

Optically active α,β-unsaturated γ-lactones : Stereospecific transformation of allene carboxylic acids

Conditions of transformation of chiral allene carboxylic acids and their esters into α,β-unsaturated γ-lactones are described. It was found that in the case of 3a and 3b the lactonisation reaction was completely stereospecific. Configuration and optical purity of the title and related compounds have been established.     

药物中磺酸酯类基因毒性杂质研究进展

该文概述了近10年来有关药物中基因毒性杂质监管指南的完善历程与相关检测方法的研究进展。介绍了基因毒性杂质从早期的完全避免到目前的阶段化毒理学关注阈值（TTC）的风险控制理念以及各主流监管机构的具体要求。作为一类重要的基因毒性杂质,磺酸酯主要来源于磺酸及衍生物与低级醇（如甲醇、乙醇、异丙醇等）之间发生的副反应,具有化学结构类型多样化的特点。该文较为详尽地介绍了磺酸酯的形成机理和文献所采用的液相色谱法和气相色谱法,并对色谱方法的选择、预处理方式、衍生化方法及相应痕量水平的灵敏度和回收率等进行了评述。由此期望为合理控制药物中磺酸酯类基因毒性杂质,为保证药物的质量安全性提供有益的指导意见。     

Catalytic,asymmetric Mannich-type reactions of alpha-imino esters bearing readily removable substituents on nitrogen

[reaction: see text] Catalytic, enantioselective Mannich-type reactions of alpha-imino esters bearing readily removable substituents on nitrogen are described. Several N-carbamate-protected alpha-imino esters, which are readily prepared from 2-bromoglycine esters using a polymer-supported amine, reacted with silicon enolates to afford the desired adducts in high yields with high enantioselectivity using a copper(II)-diamine complex. Easy deprotection of the product amine and transformation to free alpha-amino acid derivatives have also been demonstrated.     

Arsenorgano-Verbindungen. XX. Synthese und Reaktionsverhalten der Diphenylarsinocarbonsäuren

Organo-arsenic Compounds. XX. Synthesis and Reactivity of Diphenylarsino Carboxylic Acids Natrium diphenylarside reacts with chlorocarboxylic acids and their amides or esters in liquid ammonia to give the corresponding diphenylarsino carboxylic acids, amides, and esters. Their properties and some reactions are described. The synthesis of secondary ω-phenylarsino carboxylic acids from 2 and 3 has been studied.     

Derivatives of unsaturated phosphonic acids Communication 7. Diesters of 2-phenoxyvinylphosphonic acid

Summary The dimethyl, diethyl, dipropyl, diisopropyl, dibutyl, diisobutyl, diallyl, dihexyl, bis(2-methoxyethyl), and bis(2-ethoxyethyl) esters of 2-phenoxyvinylphosphonic acid have been prepared by the action of 2-phenoxyvinyl-phosphonic dichloride on alcohols in presence of pyridine. The properties of these esters have been described.     

Stickstoffhaltige siliciumorganische Verbindungen. CXIX. Synthese der cyclischen siliciumorganischen Ester von Diethanolaminen

Nitrogen Containing Organosilicon Compounds. CXIX. Synthesis of Cyclic Organosilicon Esters of Diethanolamines . The synthesis and characteristics of 41 new cyclic organosilicon esters of diethanolaminnes — 1,3-dioxa-6-aza-2-silacyclooctanes — are described. Nine various methods of their preparation have been investigated, including the new ones used for the first time in this work. The comparative valuation of the investigated methods is presented.     

Liquid chromatographic analysis of sebum lipids and other lipids of medical interest

A technique is described for the high-pressure liquid chromatographic (HPLC) analysis of sebum lipid classes. The lipid present in sebum are separated by gradient elution HPLC from a microparticulate silica column and detected using a moving-wire detector. The system described can be linked to a computer. Quantitation can be carried out by comparing peak areas obtained with those of an internal standard. Peak trapping for further investigations of the separated components, for example by gas chromatography-mass spectrometry, is very easy. Sebum lipids are separated into the following lipid classes: hydrocarbons and squalene, cholesterol esters and wax esters, fatty acids as their methyl esters, triglycerides, 1,3-diglycerides, 1,2-diglycerides, free cholesterol, monoglycerides and other polar materials. Besides to sebum, the method has been successfully applied to other lipid mixtures, such as serum lipids. Examples of other applications are shown.     

Palladium-catalyzed intramolecular alpha-arylation of alpha-amino acid esters.

The Pd-catalyzed intramolecular alpha-arylation of alpha-amino acid esters is described. Starting from readily available amino acids, the synthesis of a variety of isoindolines and tetrahydroisoquinoline carboxylic acid esters has been accomplished. Additionally, fused tricyclic systems can be efficiently prepared from cyclic amino acid esters. Reaction conditions have been found that allow the use of tert-butyl ester and N-(benzyloxycarbonyl) protecting groups.     

Microextraction methods for the determination of phthalate esters in liquid samples: A review

1,2‐Benzenedicarboxylic acid esters, commonly referred to as phthalate esters, form a group of compounds that are mainly used as plasticizers in polymers. Because phthalate esters are not chemically bound to the plastics, they can be released easily from products and migrate into the food or water that comes into direct contact. Due to their widespread use, they are considered as ubiquitous environmental pollutants. Phthalate esters are regarded as endocrine disrupting compounds by means of their carcinogenic effect. Phthalate esters can be analyzed by gas chromatography or high‐performance liquid chromatography, however, their sensitivity and selectivity limit their direct use for determination of phthalates at very low level of concentrations exist in environmental samples with complex matrices. Therefore a sample pretreatment prior to their analysis is necessary. In this review, the historical development and overview of sample preparation methodologies have briefly been discussed and a comprehensive application of these methods in combination with different analytical techniques for preconcentration and determination of phthalate esters in various matrices have been summarized. Finally, a critical comparison of the different approaches in terms of enrichment factors achieved, extraction efficiency, precision, selectivity and simplicity of operation is provided.     

Derivatives of unsaturated phosphonic acids Communication 6. Diesters of 2-isoprotoxy-, 2-isobutoxy-, and 2-isopentyloxy-vinylphosphonic acids

Summary The dimethyl, diethyl, dipropyl, diisopropyl, dibutyl, diisobutyl, diallyl, dihexyl, bis(2-methoxyethyl), and bis(2-ethoxyethyl_ esters of 2-isopropoxy-, 2-isobutoxy-m and 2-isopentyloxy-vinylphosphonic acids have been prepared by the action of alcohols on 2-isopropoxy-, 2-isobutoxy-, and 2-isopentyloxy-vinylphosphonic dichlorides. The properties of the esters have been described.     

饮水中痕量邻苯二甲酸酯类化合物的色谱测定

本文提出了包括疏水吸附剂富集及气相色谱或液相色谱分析方法。报道了邻苯二甲酸酯在Amberlite XAD-2和SS401上的富集容量,研究了水样pH和流速对回收率的影响,GC采用填充柱或毛细柱,HPLC采用细径反相柱,适用于分析大分子量邻苯二甲酸酯。当取样量为10升时,本法的检测极限为ppb水平。     

Synthesis of Β- isopropylthioethyl esters of some thio acids of trivalent arsenic

Conclusions Five previously unknown-isopropylthioethyl esters of thioarsenious, ethylthioarsinous, phenylthioarsinous, diphenylthioarsinous, and thiophenarsazinous acids have been synthesized; their properties have been described.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2554–2556, November, 1967.     

Polyhydroxy and polyethyleneglycol (meth)acrylate polymers: physical properties and general studies for their use as electrophoresis matrices.

A new series of materials have been tested for their suitability as electrophoresis matrices. The mechanical and optical properties of gels composed of polyethyleneglycol (meth)acrylate esters or polyhydroxy (meth)acrylate esters in water and in various concentrations of organic solvents are described. Several crosslinkers including polyethyleneglycol and polyhydroxy di(meth)acrylates, piperazine diacrylate, and bisacrylamide were used in these studies. Electrophoretic migration and separation of a series of protein standards through polyethyleneglycol methacrylate (PEGM) 200, PEGM 400, and glyceryl methacrylate is demonstrated. Further, copolymerization of all of the monomers with acrylamide was performed and the distribution of monomer incorporation into the polymer network calculated. All monomers and copolymers that were examined by IR spectroscopy showed greater than 99% polymerization. These results justify their further study for biomolecule separations.     

The reaction of quinol-6-ylmethyleneamines with dialkylphosphites. synthesis of quinol-6-methyleneamines and of dialkyl esters of arylamino(quinol-6-yl)methylphosphonic acids

Syntheses of quinol-6-ylmethyleneamines are described. The addition of dialkyl phosphites to the azomethine grouping of the quinol-6-yl-methyleneamines in the presence of sodium methoxide has been studied. Eighteen new dialkyl esters of arylamino(quinol-6-yl)methylphosphonic acids have been synthesized.