Synthesis of 10-Hydroxy- and 9-Oxo-2e-Decenoic Acids from Oleic Acid

A practical synthesis of biologically active 10-hydroxy- and 9-oxo-2E-decenoic acids, components of mandibular gland secretion of honeybee (Apis mellifera L.), is developed using ozonolysis-reduction of oleic acid and 1,9-diacetoxynon-1-ene in the key steps.     

Synthesis and Crystal Structure of Drum Organooxotin Clusters from Heteroaromatic Carboxylic Acid [PhCH2Sn（O）（O2CC5H4N）]6 and[PhCh2Sn）（O）（O2CC4H3O）]6

IntroductionRecentlywehaveinvestigatedthestructuralchemistryofanumberofdi ortri organotinheteroaromaticcarboxyl ates.1 5Thesestudieshaveshownthatthestructureoforgan otinheteroaromaticcarboxylatesisdependentonboththena tureofthealkylorarylsubstituentboundtothetinatomandthetypeofcarboxylateligand .Inparticular,majorstructuralvariationsareobservedwhencarboxylateligandcontainsanadditionaldonoratom ,suchasapyridineNatom ,availableforcoordinationtotheSnatom .1 3,5 8Wehavenowturnedtothemonoorganotin…     

TLC of substituted pyridines. XII. Hydroxy derivatives

Investigations were made to determine the TLC properties of monosubstituted pyridines. The primary aim was to identify and quantitatively

2. R_f Values of Monohydroxypyridines and other Monosubstituted Pyridines (Monoamines and Monocarboxylic Acids) in Systems I and II

determine the monohydroxypyridines formed during in vitro chemical and enzymatic hydroxylation experiments.TLC studies were carried out not only on the monosubstituted pyridines, but also on 2,3-di-OH-pyridine and 3-OH-pyridine-N-oxide.The UV absorption spectra of pyridine and its substituted derivatives were recorded at a concentration of 10⁻³ M in ethanol, and were compared.The best TLC detection of these derivatives was elaborated too.     

Synthesis of a Multifunctional Pheromone of the Honeybee Apis mellifera Via Condensation of 7-Oxooctanal with Malonic Acid

Condensation of 7-oxooctanal with malonic acid in a Doebner reaction produces 9-oxo-2E-decenoic acid (42% yield) and a comparable amount of products from Tishchenko disproportionation of the starting aldehyde (7-oxooctyl-7-oxooctanoate) and re-esterification by acetic acid (7-oxooct-1-ylacetate and 7-oxooctanoic acid).     

An LC method for monitoring medium-chain fatty acid permeation through CaCo-2 cell monolayers

A simple method was developed for monitoring the permeation of medium-chain fatty acids of C8 (octanoic acid) and C10 (decanoic acid) through CaCo-2 cell monolayers by high-performance liquid chromatography with electrochemical detection (HPLC-ECD). The detection was made based on the electrochemical reduction prepeak of quinone caused by acids, requiring the fabrication of a two-channel HPLC-ECD system. In one channel, acetonitrile–water (7:3, v/v) was used as a mobile phase to separate acids by a C30 column. In the other channel, acetonitrile–water (7:3, v/v) containing 6 mmol/L 3,5-di-t-butyl-1,2-benzoquinone and 20 mmol/L LiClO₄ was used as a quinone solution to detect acids by an electrochemical cell with a glassy carbon working electrode. In this HPLC-ECD system, eluted acids were mixed with the quinone solution in a post column fashion to obtain current signals caused by acids. The peak area was found to be linearly related to the acid amount ranging from 25 to 1,000 pmol (r > 0.992). The detection limits of octanoic acid and decanoic acid were 7.5 and 8.8 pmol, respectively. Octanoic acid and decanoic acid spiked into cell culture media samples were extracted with acetonitrile and their recoveries were more than 89.5% with an RSD of less than 8.2%. This method was applied to the permeation experiment of octanoic acid and decanoic acid with CaCo-2 cell monolayers formed on the Transwell? system. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. This work was partly presented at The Physical Pharma Forum 2008 on March 24, 2008 in Tokyo, Japan.     

Synthesis of phosphinic and phosphoric analogs of aspartic acid

Approaches to the synthesis of 1-amino- and 2-amino-2-carboxyethylphosphinic and-phosphoric acids have been studied. A convenient method for the preparation of phosphinic acids is the reactions of ethyl diethoxymethylphosphonite with ethyl acetamidomethylenemalonate and ethyl 2-acetamidoacrylate.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 2066–2069, August, 1996.     

Novel modified chiral NiII complexes with the Schiff bases of (E)-and (Z)-2-aminobut-2-enoic acids: Synthesis and study

Ni^II complexes with the Schiff bases of (E)-and (Z)-2-aminobut-2-enoic acids were obtained with (S)-N-(2-benzoylphenyl)-1-(2-chlorobenzyl)pyrrolidine-2-carboxamide and (S)-N-(2-benzoylphenyl)-1-(3,4-dimethylbenzyl)pyrrolidine-2-carboxamide as new chiral auxiliaries. Asymmetric addition of nucleophiles to the C=C bond of these complexes was studied. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 428–435, March, 2006.     

Synthesis of (+)- and (−)-Phaselic Acid

The syntheses of both enantiomers of phaselic acid (2-O-caffeoylmalate) are described. The previously unreported acetate-protected caffeic acid anhydride was used with appropriately protected malic acid derivatives as coupling partners to provide fully protected phaselic acid. Sequential unmasking of the protecting groups afforded phaselic acid in an acceptable overall yield.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Synthesis of stereoisomeric 4-(2-methylindolin-1-yl)- and 4-(2-methylindol-1-yl) derivatives of glutamic acid

The reaction of dimethyl (2S,4RS)-N-phthaloyl-4-bromoglutamate with 2-methylindoline afforded diastereomeric 4-(2-methylindolin-1-yl)-(S)-glutamic acid derivatives, whose oxidation gave rise to 4-(2-methylindol-1-yl)-(S)-glutamic acid derivatives.     

Synthesis ofN-methacryloyl- andN-allyl-substituted derivatives of ethyl 5-oxo-2-pyrrolidinecarboxylate

A method for the preparation of previously unknownN-methacryloyl- andN-allyl-derivatives of ethyl 5-oxo-2-pyrrolidinecarboxylate has been developed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 767–769, March, 1996.     

Effect of sialic acid content on glycoprotein pI analyzed by two‐dimensional electrophoresis

2‐DE is broadly used for quantitative analysis of differential protein expression in complex mixtures such as serum samples or cell lysates. PTMs directly influence the 2‐DE pattern, and knowledge of the rules of protein separation is required in order to understand the protein distribution in a 2‐DE gel. Glycosylation is the most common PTM and can modify both the molecular weight and the pI of a protein. In particular, the effect of charged monosaccharides (mainly sialic acids, SAs) on the 2‐DE pattern of a protein is of major interest since changes in sialylation are regularly observed in comparative studies. Little is known about the pI shift of a glycoprotein induced by the presence of SAs, or whether this shift is the same for all glycoproteins. To address this issue, this study examined the influence of SA on the 2‐DE pattern of three serum glycoproteins (haptoglobin, α1‐antitrypsin and ribonuclease 1), which N‐glycan chains had been previously characterised, and reviewed existing bibliographic data. The SA content of the different glycoforms of a glycoprotein showed a negative linear correlation with the pI, although the slope varied among the studied glycoproteins. We also described a positive correlation between the protein pI and the pI decrease per SA molecule.     

Transition metal complexes of pyrazinecarboxylic acids with neutral hydrazine as a ligand

New divalent Co, Ni, Zn and Cd pyrazinecarboxylate hydrazinates of the formulae M(pyzCOO)₂·nN₂H₄·xH₂O and Mpyz(COO)₂·N₂H₄·xH₂O obtained by the reaction of respective metal nitrate hydrates with 2-pyrazinecarboxylic (HpyzCOO)/2,3-pyrazinedicarboxylic (H₂pyz(COO)₂) acid and hydrazine hydrate have been characterized on the basis of analytical, spectroscopic (electronic and infrared), thermal and X-ray powder diffraction studies. The electronic spectroscopic data suggest that the cobalt and nickel complexes are of spin-free (high-spin) type with octahedral geometry. The IR absorption bands of N-N stretching in the range 980-972 cm^-1 unambiguously prove the bidentate bridging nature of the N₂H₄ ligand. The hydrazinate complexes of 2,3-pyrazinedicarboxylate lose hydrazine molecule exothermally, whereas 2-pyrazinecarboxylate compounds lose the same endothermally. Further, all the complexes undergo endothermic (dehydration and/or dehydrazination) followed by exothermic decomposition except the Zn and Cd complexes of 2,3-pyrazinedicarboxylate, which show only exothermic decomposition. In order to know the isomorphic nature among the complexes, the X-ray powder patterns have been compared.     

Synthesis,crystal structure and properties of two terbium complexes with 2,2′-bipyridine

Two new complexes {[Tb(2-IBA)₃ · 2,2′-bipy]₂ · C₂H₅OH} (1) and [Tb(2-ClBA)₃ · 2,2′-bipy]₂ (2) (2-IBA = 2-iodobenzoate; 2-ClBA = 2-chlorobenzoate; 2,2′-bipy = 2,2′-bipyridine) were prepared and their crystal structures determined by X-ray diffraction. Complex 1 is composed of two types of binuclear molecules, [Tb(2-IBA)₃ · 2,2′-bipy]₂ (a) and [Tb(2-IBA)₃ · 2,2′-bipy]₂ (b), and an uncoordinated ethanol molecule. In molecule (a), two Tb³⁺ ions are linked by four 2-IBA groups, all bidentate-bridging. In molecule (b), two Tb³⁺ ions are held together by four 2-IBA groups in two coordination modes, bidentate-bridging and chelating-bridging. In the two molecules, each Tb³⁺ ion is further bonded to one chelating 2-IBA group and one chelating 2,2′-bipy molecule, resulting in coordination numbers of eight for (a) and nine for (b). The structural characteristics of 2 are similar to that of molecule (b) in 1. The two complexes, 1 and 2, both emit strong green fluorescence under ultraviolet light with the ⁵D₄ → ⁷F _j (j = 6–3) emission of Tb³⁺ ion observed.     

Acid–base characterization of 5-hydroxypyrazine-2-carboxylic acid and the role of ionic equilibria in the optimization of some process conditions for its biocatalytic production

This paper describes the use of potentiometric titration to determine the relevant acid–base properties of 5-hydroxypyrazine-2-carboxylic acid (5OH-PYCA), an important intermediate in the production of tuberculostatics. The data obtained were used for calculation of the dissociation constants of 5OH-PYCA. It was found that 5OH-PYCA dissociates in two steps, with the corresponding dissociation constants pK _a1=3.42 and pK _a2=7.96, designating 5OH-PYCA as a medium weak acid (1st step). The distribution diagram of dissociated species and the buffer-strength diagram of 5OH-PYCA provide useful information about its behaviour at different pH. The ionic equilibria data obtained can be used for selection of the optimum pH for biotransformation of pyrazine-2-carboxylic acid (PYCA) and for prediction of pH changes during the biotransformation. These data can also be used for selection of the optimum pH for precipitating 5OH-PYCA in downstream processing. All computations have been optimized by mathematical modelling using Solver.     

Synthesis and Microbial Studies of New Pyridine Derivatives-Ill

2-Amino substituted benzothiazole 4a--4I and p-acetamidobenzenesulfonyl chloride 2 were used to prepare 2-（p-aminophenylsulfonamido） substituted benzothiazole 6a--6I using mixture of pyridine and acetic anhydride which formed an electrophilic complex （N-acetyl pyridinium） to facilitate condensation to give desired product by removal of HC1. 2-{p-[（3-Carboxypyrid-2-y1）amino]phenylsulfonamido}benzothiazoles 8a--81 were synthesized from 2-chloropyridine-3-carboxylic acid 7 and 6a--6I in 2-ethoxy ethanol using Cu-powder and K2CO3. Acid chlorides 9a--91 were condensed with 2-hydroxyethyl piperazine 10 and 2,3-dichloropiperazine 11 for amide deriva- tives 2-（p-（（3-（4-（2-hydroxyethy1）piperazin-1-ylcarbonyl）pyrid-2-y1）amino）phenylsulfonamido）benzothiazoes 12a -121 and 2-{p-[3-（2,3-dichloropiperazin-l-ylcarbonyl）pyrid-2-ylamino]phenylsulfonamido}benzothiazoles 13a- 131 respectively. The structures of the new compounds have been established on the basis of their chemical analysis and spectral data （IR, 1↑H NMR and mass）. All the compounds have been screened for their antibacterial and antifungal activities.     

Cu(II)/Cd(II) coordination polymers based on polycarboxylate and 2-(2-pyridyl)benzimidazole

Three polycarboxylate coordination polymers containing 2-(2-pyridyl)benzimidazole as co-ligand, [Cu(Bdc)(2-PyBIm)] _n (1), [Cu(HBtc)(2-PyBIm)] _n (2) and [Cd₂(HBtc)₂(2-PyBIm)₂] _n ·; nH₂O (3) (H₂Bdc?=?1,4-benzenedicarboxylic acid; H₃Btc?=?1,3,5-benzenetricarboxylic acid), have been synthesized and characterized by elemental analyses, IR spectra, TG-DSC and X-ray structural analyses. Complex 1 is a one-dimensional zigzag chain in which the Cu(II) is cis six-coordinated by two chelating carboxyl groups and a 2-PyBIm ligand. Complex 2 is a two-dimensional (4, 4) network in which H₃Btc is partially deprotonated. Complex 3 has a three-dimensional framework in which one Cd(II) is six-coordinate and the other is seven-coordinate. All 2-PyBIm groups are neutral, chelating, bidentate ligands in 1–3. These complexes are quite thermally stable. The luminescence of 3 has also been investigated.     

2-(2-Hydroxy-4-methoxybenzoyl)benzoic acid derivatives of Group 4 metal alkoxides

Continued exploration of the coordination behavior of derivatives of 2-benzophenone-based ligands with metal alkoxides ([M(OR)₄]) was undertaken from the reaction of 2-(2-hydroxy-4-methoxybenzoyl)benzoic acid (H₂-OBzA) with a series of Group 4 precursors. The products of these reactions were identified as: [(OR)₂Ti(μ-(c,c-OBzA))]₂ (OR?=?OCHMe₂ (OPrⁱ; 1 ?2tol); OCMe₃ (OBu^t; 2 ?THF); OCH₂CMe₃ (ONep; 3)), [[(OPrⁱ)₃Ti(μ-OPrⁱ)Ti(OPrⁱ)₂]₂(μ-(μ_c,μ-OBzA))₂]₂ (4), [(ONep)₃Zr(μ-ONep)₂Zr(ONep)₂]₂(μ-(c,μ-OBzA)₂) (5 ?tol), [(py)(OBu^t)₃Zr]₂(μ-(c,c-OBzA)) (6), [(OBu^t)₂Hf(μ-OBu^t)]₂(μ-(c,η¹-OBzA)) (7) where ‘c’?=?chelating or η²; ‘μ’?=?bridging or η¹,η¹(O,O’); and μ_c?=?bridging chelating or η¹,η¹(O,O’); η^2?:?η¹. The metal centers for each of these compounds adopt a pseudo-octahedral geometry employing the OBzA ligand in numerous binding modes. The different functional oxygens (carboxylate, hydroxyl, and carbonyl) were employed in a variety of coordination modes for 1–7. The complexity of these OBzA-modified compounds is driven by a combination of the coordination behavior of the OBzA moieties, the size of the metal cation, and the pendant chain of the OR ligand. Solution NMR indicates a complex structure exists in solution that was considered to be consistent with the solid-state structure.     

Syntheses and crystal structures of mixed-ligand copper(II)–imidazole–carboxylate complexes

The syntheses, characterization, and crystal structures of the reaction products of Cu²⁺ with imidazole (Himz) and different aromatic carboxylates, viz.: [Cu(Himz)₂(cinn)₂(H₂O)] (1), [Cu(Himz)₂(paba)₂] (2) and [Cu(Himz)₂(clba)₂] (3) (cinn^– = C₉H₇O₂^–, paba^– = C₇H₆NO₂^–, clba^– = C₇H₄ClO₂^–) are described and studied by spectroscopic (UV–visible, FTIR) measurements. Single-crystal X-ray diffraction analyses indicate that each complex is monomeric. The metal ion in 1 adopts square-pyramidal coordination geometry arising from two imidazole nitrogens, two cinnamate oxygens, and an apical aqua. The metal ions of 2 and 3, however, assume a square planar configuration, which is realized by coordination of two nitrogens of two imidazoles and two oxygens; in both complexes, the imidazole moieties are trans to each other. TGA results indicate that upon heating, these complexes lose their carboxylate anions first, followed by removal of the imidazole molecules.     

基于2-硫代巴比妥酸构筑零维原子簇{[Cu6(H2tba)6]·2DMF·xSolvent}、二维层状{[Sc(H2tba)3(DMF)]·2DMF}n和三维网状{[Fe(H2tba)2(H2O)2]·2DMF}n

分别以Cu (ClO₄)₂·6H₂O、Sc (ClO₄)₃·6H₂O和Fe (ClO₄)₃·9H₂O为金属盐,2-硫代巴比妥酸(H₃tba)为配体,通过扩散反应得到了3种不同结构的配合物{[Cu₆(H₂tba)₆]·2DMF·xSolvent}(1)、{[Sc (H₂tba)₃(DMF)]·2DMF}_n(2)和[Fe (H₂tba)₂(H₂O)₂]_n(3),并用红外光谱、元素分析、热重分析和粉末X射线衍射对配合物进行了表征。单晶X射线衍射结构分析表明配合物1是一个具有三方反棱柱构型的六核铜原子簇合物,配合物2是一个具有二维层状结构的化合物,配合物3是一个具有三维网状结构的配位聚合物。配合物1在390 nm光照激发下在735 nm处有强的荧光发射峰。