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Characterization of isomeric cationic porphyrins with beta-pyrrolic substituents by electrospray mass spectrometry: the singular behavior of a potential virus photoinactivator.

Electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS) have been used to differentiate the 2- and 4-methylpyridyl isomers of free-base and metallated cationic beta-vinylpyridylporphyrins. The analysis by ESI-MS/MS of the deuterated analogs and semiempirical calculations of structural and electronic parameters were also undertaken. The two free-base isomers are easily differentiated by ESI-MS/MS but the presence of a metallic center renders differentiation of the metallated isomers less effective. The data acquired show that of all the studied compounds, the free-base 2-methylpyridyl isomer, which was operative in the in vitro photoinactivation of Herpes simples virus, has a different gas-phase behavior. Local distortion of the macrocycle due to the presence of the beta-vinylpyridyl substituent occurs for all the compounds, but a different electron density distribution can account for the observed gas-phase behavior of this potential virus photoinactivator.

Antiviral Agents↗

Determination of the absolute number of Escherichia coli membrane vesicles that catalyze active transport.

Transport of vinylglycolate (2-hydroxy-3-butenoic acid) via the lactate transport system is the limiting step for covalent labeling of membrane vesicles prepared from E. coli ML 308-225. Thus, the rate and extent of vinylglycolate labeling is stimulated about 10-fold by ascorbate-phenazine methosulfate, and stimulation is abolished by 2,4-dinitrophenol and by phospholipase treatment, neither of which affect the rate of vinylglycolate oxidation. [(3)H]Vinylglycolate of high specific activity has been prepared, and vesicles have been labeled with this compound in the presence of ascorbate-phenazine methosulfate. Examination of these preparations by high resolution radioautography in the electron microscope demonstrates that virtually all of the vesicles are labeled. The experiments provide a strong indication that most, if not all, of the membrane vesicles in these preparations catalyze active transport.

Ascorbic Acid↗

QSAR study of anticoccidial activity for diverse chemical compounds: prediction and experimental assay of trans-2-(2-nitrovinyl)furan.

In this work we report a QSAR model that discriminates between chemically heterogeneous classes of anticoccidial and non-anticoccidial compounds. For this purpose we used the Markovian Chemicals in silico Design (MARCH-INSIDE) approach J. Mol. Mod.2002, 8, 237-245; J. Mol. Mod.2003, 9, 395-407]. Linear discriminant analysis allowed us to fit the discriminant function. This function correctly classifies 86.67% of anticoccidial compounds and 96.23% of inactive compounds in the training series. Overall classification is 94.12%. We validated the model by means of an external predicting series, with 86.96% of global predictability. Remarkably, the present model is based on topological as well as configuration-dependent molecular descriptors. Therefore, the model performs timely calculations and allows discrimination between Z/E and chiral isomers. Finally, to exemplify the use of the model in practice we report the prediction and experimental assay of trans-2-(2-nitrovinyl)furan. It is notable that lesion control was 72.86% at mg/kg of body weight with respect to 60% at 125 mg/kg for amprolium (control drug). The back-projection map for this compound predicts a high level of importance for the double bond and for the nitro group in the trans position. We conclude that the MARCH-INSIDE approach enables the accurate fast track identification of anticoccidial hits. Moreover, trans-2-(2-nitrovinyl)furan seems to be a promising drug for the treatment of coccidiosis.

Animals↗

Potential cerebral perfusion agents: synthesis and evaluation of a radioiodinated vinylalkylbarbituric acid analogue.

A new iodinated barbiturate has been prepared. Treatment of 5-chloropentyne and propargyl bromide with diethyl 2-ethyl-2-sodiomalonate (DESM) provided diethyl 2-ethyl-2-(1-pentyn-5-yl)malonate (3) and diethyl 2-ethyl-2-propargylmalonate (4), respectively. Similar condensation of DESM with (E)-(5-iodo-1-penten-1-yl)boronic acid (9) or the reaction of catecholborane with 3 provided diethyl (E)-2-ethyl-2-(1-borono-1-penten-5-yl)malonate (8). The direct sodium iodide-chloramine-T iodination of 8 or the treatment of (E)-1,5-diiodo-1-pentene (10) with DESM provided diethyl (E)-2-ethyl-2-(1-iodo-1-penten-5-yl)malonate (11). The condensation of functionalized malonates 3, 4, and 11 with urea in the presence of a base provided the corresponding barbiturates, 5-ethyl-5-(1-pentyn-5-yl)-(5), 5-ethyl-5-propargyl- (6), and (E)-5-ethyl-5-(1-iodo-1-penten-5-yl)barbituric acid (12), respectively. (E)-6-(Ethoxycarbonyl)-1-iodo-1-octene-6-carboxylic acid (13) was isolated as the hydrolytic byproduct of 11. Compound 13 decarboxylated under vacuum to provide ethyl (E)-1-iodo-1-octene-6-carboxylate (14). The 125I-labeled congeners of 12 and 13 were synthesized in the same manner and evaluated in rats. The barbiturate 12 exhibited significant brain uptake (approximately 1% dose after 5 min), demonstrating that iodinated barbiturates freely cross the intact blood-brain barrier.

Animals↗

Diethyl [(Z)-1-iodo-2-phenyl-1-hexenyl]phosphonate.

The crystal structure of the title compound, C16H24IO3P, is composed of independent molecules, in which one of the phosphonate ethoxy groups is disordered over two positions. The other ethoxy group lies sandwiched between two phenyl rings and, as a result, is ordered. This constrained environment also leads to two C-H...centroid interactions, one intra- and one intermolecular. Examination of the extended structure reveals the presence of chains of molecules held together by I...O interactions.

Benzene Derivatives↗

Biosynthesis of p-aminophenylalanine: part of a general scheme for the biosynthesis of chorisimic acid derivatives.

p-Aminophenylalanine is biosynthesized in Vigna vexillata (L.) A. Rich. from shikimic acid through a pathway different from that giving phenylalanine and tyrosine. Experiments with 1,6-14C-labelled shikimic acid demonstrate that the C3-side chain in p-aminophenylalanine is attached to the original C-1 in shikimic acid. The biosynthesis of p-aminophenylalanine in Vigna vexillata probably follows the same pathway as the biosynthesis of this amino acid in Streptomyces species where it is known to be an intermediate in the biosynthesis of chloramphenicol. It is proposed that the biosynthesis takes place through chorismic acid, 4-amino-3-enolpyruvylcyclohexa-1,5-dienecarboxylic acid, 3-(4-amino-1-carboxycyclohexa-2,5-dienyl) pyruvic acid, and 4'-aminophenyl-yruvic acid. It is proposed that chorismic acid can gave rise to 4-amino-3-enolpyruvylcyclohexa-1,5-dienecarboxylic acid, 2-amino-3-enolpyruvylcyclohexa-4,6-dienecarboxylic acid, and isochorismic acid, and that these three compounds and chorismic acid itself by simple rearrangements and elimination reactions can give rise to most known chorismic acid derivatives, i. e.p-hydroxybenzoic acid, 3,4-dihydroxy-3,4-dihydrobenzoic acid, phenylalanine, tyrosine, p-aminobenzoic acid, p-aminophenylalanine, anthranilic acid, 2-amino-3-hydroxy-2,3-dihydrobenzoic acid, 3-(3-carobxyphenyl) alanine, 3-(3-carbocy-4-hydrocyphenyl) alanine, salicylic acid, and 2,3-dihydroxy2,3-dihydrobenzoic acid.

Amines↗

cis-trans-isomerization of [E]-5-(2-bromovinyl)-2,2'-anhydrouridine in vivo in rats.

1. [E]-5-(2-bromovinyl)-2,2'-anhydrouridine [( E]BVANUR) has considerable antiviral activity against herpes simplex virus type 1 (HSV-1). 2. [E]BVANUR is not a substrate of pyrimidine nucleoside phosphorylases, but it is an inhibitor of uridine phosphorylase (Ki = 450 nM). 3. [E]BVANUR (trans-isomer, parent compound) undergoes isomerization to [Z]BVANUR (cis-isomer), the only metabolite in rat, which was identified by h.p.l.c., mass spectra and n.m.r. spectroscopy. 4. Absorption of the drug from the gastrointestinal tract after oral administration is minimal. Absorption of [E]BVANUR from the abdominal cavity after i.p. administration was slow.

Animals↗

Synthesis and radiochemistry of 2,4-disubstituted 17 alpha-iodovinylestradiols.

This report details the preparation of three compounds which are structurally designed to have depressed metabolism and/or conjugation: 2,4-dibromo-, 2,4-dichloro-, and 2,4-dimethyl-17 alpha-iodovinylestradiol. Their synthesis includes the use of two novel transformations based upon tin chemistry: preparation of an intermediate 17 alpha-vinylstannanes via stannylcupration of a 17 alpha-ethynyl steroid, and preparation of the 2,4-dimethyl functionality via a palladium catalyzed coupling of 2,4-dibromoestrone acetate with tetramethyltin. The preparative radiochemistry of these three materials is also described.

Estradiol↗

Isolation and structures of two divinyl ether fatty acids from Clematis vitalba.

[1-14C]Linolenic acid was incubated with a homogenate of leaves of Clematis vitalba, a plant belonging to the Ranunculaceae family. Analysis of the reaction product by reversed-phase high-performance liquid radiochromatography demonstrated the presence of the following labeled oxylipins: 12-oxo-10, 15(Z)-phytodienoic acid, 9(S)-hydroxy-10(E), 12(Z), 15(Z)-octadecatrienoic acid, omega5(Z)-etherolenic acid, and 9-[1'(E), 3'(Z),6'(Z)-nonatrienyloxy]-8(Z)-nonenoic acid [8(Z)-colnelenic acid]. The last compound was a new divinyl ether FA, and an analogous compound, i.e., 9-[1'(E),3'(Z)-nonadienyloxy]-8(Z)-nonenoic acid [8(Z)-colneleic acid], was obtained following incubation of linoleic acid with the Clematis homogenate. Structures of the two divinyl ethers were assigned by spectral and chromatographic comparison with authentic compounds prepared synthetically using previously described methodology. Separate incubation of the 9- and 13-hydroperoxides of linolenic acid demonstrated that the first hydroperoxide served as the precursor of 8(Z)-colnelenic acid and indicated the presence in C. vitalba of a new divinyl ether synthase acting on 9-lipoxygenase-generated hydroperoxides. A close structural relationship between this enzyme and the well-studied divinyl ether synthase in the potato and tomato seems likely.

Chromatography, High Pressure Liquid↗

Preparation and investigation of cross-linked copolymers containing antitumour agents.

Polymers with anti-tumour activity were prepared by reactions of the iso-propyl ester of p-bis(2-chloroethyl) aminophenylalanine with free aldehyde, epoxide and hydroxyl groups within macroporous cross-linked copolymers of either divinylbenzene and methacrylaldehyde, or glycidyl methacrylate and ethylene dimethacrylate, or 2-hydroxyethyl methacrylate and ethylene dimethacrylate. For use as pharmacologically active compounds bonded on polymers, the chemical stability of the bond between these compounds and the polymer is of importance and for this reason an investigation was carried out on the course of the hydrolysis of azomethine compounds prepared by reactions between free aldehyde groups in copolymers of divinylbenzene and methacrylaldehyde with the iso-propyl ester of p-bis(2-chloroethyl) aminophenylalanine. The highest initial rate of hydrolysis was observed at the highest proton concentration. The testing in vivo of antitumour activity of the isopropyl ester of p-bis(2-chloroethyl)-aminophenylalanine embedded within the cross-linked copolymer was carried out intraperitoneally on five experimental transplanted tumours.

Acrolein↗

Structure-activity relationships of (E)-5-(2-bromovinyl)uracil and related pyrimidine nucleosides as antiviral agents for herpes viruses.

A series of (E)-5-(2-bromovinyl)uracil analogues and related nucleosides was synthesized, and their antiviral activities were evaluated. (E)-5-(2-Bromovinyl)-2'-deoxy-L-uridine (L-BVDU, 2), 1-(beta-L-arabinofuranosyl)-(E)-5-(2-bromovinyl)uracil (L-BVAU, 4), (E)-5-(2-bromovinyl)-1-(2-deoxy-2-fluoro-beta-L-ribofuranosyl)uracil (L-FBVRU, 8) and (E)-5-(2-bromovinyl)-1-(2-deoxy-2-fluoro-beta-L-arabinofuranosyl)urac il (L-FBVAU, 10) were synthesized via appropriate 5-iodouracil analogues from L-arabinose. D- and L-Oxathiolane and -dioxolane derivatives 13, 16, 20, 21, and 29-34 were prepared by glycosylation reaction of the oxathiolane and dioxolane intermediates with silylated uracil analogues using TMSI as the coupling agent. The synthesized compounds were evaluated in cell cultures infected with the following viruses: varicella zoster virus (VZV), Epstein Barr virus (EBV), and herpes simplex virus types 1 and 2 (HSV-1 and HSV-2). Among the tested compounds, beta-L-CV-OddU (29), beta-L-BV-OddU (31), and beta-L-IV-OddU (33) exhibited potent in vitro antiviral activity against VZV with EC(50) values of 0.15, 0. 07, and 0.035 microM, respectively, and against EBV with EC(50) values of 0.49, 0.59, and 3.91 microM, respectively.

Antiviral Agents↗

Antirhino/enteroviral vinylacetylene benzimidazoles: a study of their activity and oral plasma levels in mice.

In an effort to find an orally bioavailable antiviral for the treatment of rhino/enteroviral infections, a series of vinylacetylene benzimidazoles (11a-o, 12, and 18a) was made. Initial studies of this class of antivirals showed that fluorine substitution on the left-hand phenyl ring in combination with the vinylacetylene moiety gave the requisite mix of physical properties to achieve good in vitro antiviral activity as well as respectable oral bioavailability in rhesus monkeys. To ascertain the generality of this finding and to broaden the scope of the structure-activity relationship (SAR), the present study concentrated on fluoro substitution of this class of molecules. The initial antiviral activity for each analogue was measured using human rhinovirus 14 (HRV-14). This served as an indicator of general antiviral activity for SAR purposes. Subsequently, the spectrum of antirhino/enteroviral activity of the more interesting analogues was evaluated through testing against a panel of seven additional rhino/enteroviruses. Broad-spectrum activity was present and consistent for all analogues tested, and it tracked closely with the antiviral activity observed against HRV-14. A simple screening protocol for oral bioavailability was established whereby compounds were administered orally to mice and plasma levels were measured. This procedure facilitated the evaluation of numerous analogues in a rapid manner. The Cmax was used as a measure of oral bioavailability to allow relative ranking of compounds. In general, fluorine substitution directly on the left-hand aromatic ring does give good oral blood levels. However, fluorine incorporation at other positions in the molecule was not as effective at maintaining either the activity or the oral plasma levels. The constructive combination of activity and oral plasma levels was maximized in three derivatives: 11a,e,g.

Administration, Oral↗

[Interferon-inducing and antiviral activity of maleic anhydride copolymers].

Data on synthesis of new polymer compounds with potential interferon-inducing and antiviral activity are presented. Maleic anhydride (MA)-based alternating copolymers, in particular, copolymers of divinyl ether with MA containing five-member oxygen cycles in the chain, as well as furan copolymers with MA, were shown to be promising interferon inducers. The antiviral activity was found in copolymers based on allene hydrocarbons.

Animals↗

The esterolytic activity of poly(N-alkylimidazoles). The effect of ester chain length in the substrate and alkyl chain length in the catalyst on the esterolytic activity of poly(N-alkylimidazoles).

In an effort to exploit the enhancement in catalytic activity which might be derived through hydrophobic interactions between polymeric catalyst and substrate, 1-methyl-5-vinylimidazole (1-Me-5-VIm), 1-methyl-4-vinylimidazole (1-Me-4-VIm), 1-butyl-5-vinylimidazole (1-Bu-5-VIm), and 1-butyl-4-vinylimidazole (1-Bu-4-VIm) have been synthesized and polymerized. In 28.5% ethanol-water, poly(1-alkyl-5-vinylimidazoles)proved to be efficient catalysts for the hydrolysis of various 3-nitro-4-acyloxybenzoic acids (Sn-, where n denotes the acyl chain length). Order of magnitude rate enhancements, as compared to the model compound, 1,5-dimethylimidazole (1,5-DMIm) were observed in the poly(1-alkyl-5-vinylimidazole)-catalyzed solvolysis of S12- and S18-. Poly(1-Me-5-VIm) catalyzes the hydrolysis of S18-88 times faster than does 1,5-DMIm. The poly(1-Me-5-VIm)-catalyzed hydrolysis of S18- in ethanol-water was analyzed in terms of a simple Michaelis-Menten type mechanism. Vmax and Km were determined to be 40.2 X 10(-7) M min-1 and 2.20 X 10(-5) M, respectively.

Chemical Phenomena↗

A new analytical material-enhanced laser desorption ionization (MELDI) based approach for the determination of low-mass serum constituents using fullerene derivatives for selective enrichment.

60]fullerene derivatives (dioctadecyl methano[60]fullerene, [60]fullerenoacetic acid, and IDA-[60]fullerene) were prepared and subjected to a comprehensive characterization study including protein binding properties and capacity. These fullerene derivatives were successfully applied as material-enhanced laser desorption/ionization (MELDI) carrier materials. It is shown that diverse functionalities result in characteristic human serum peak patterns (m/z 2000-20 000) in terms of signal intensity as well as the number of detectable masses. In addition, the fullerene derivatives clearly provided differences in the low molecular weight mass region (m/z 1000-4000) after elution of the adsorbed serum constituents, and [60]fullerenoacetic acid was the most effective carrier material. Novel high-speed, monolithic, high-resolution capillary columns, prepared by thermally initiated copolymerization of methylstyrene (MSt) and 1,2-bis(p-vinylphenyl)ethane (BVPE) were employed for eluate separation and target spotting. Thus, serum compounds in the low-mass range were successfully fractionated and subjected to MALDI-MS/MS analysis. This contribution, hence, proposes a new "top-down" strategy for proteome research enabling protein profiling as well as biomarker identification in the low-mass range using selective enrichment, high-resolution separation, and offline MALDI-MS/MS evaluation.

Adsorption↗

Pathway for ubiquinone biosynthesis in Escherichia coli K-12: gene-enzyme relationships and intermediates.

Seven ubiquinone-deficient mutants of Escherichia coli, each of which accumulates two phenolic precursors of ubiquinone, have been characterized, and the accumulated compounds have been identified. The mutants accumulate small quantities of 2-octaprenyl-6-methoxyphenol, which was isolated and characterized by nuclear magnetic resonance and mass spectrometry, and relatively large amounts of 2-octaprenylphenol, a compound previously identified from E. coli. They also accumulate small quantities of a compound identified as 2-(hydroxyoctaprenyl)phenol although the relevance of this compound to the biosynthesis of ubiquinone is not clear. The results of genetic analysis suggest that each of the mutants carries a mutation in a gene (designated ubiH) which is located at about min 56 on the E. coli chromosome and is co-transducible with the serA and lysB genes. Based on information obtained from this and previous studies with ubiquinone-deficient mutants, a pathway is proposed for ubiquinone biosynthesis in E. coli, and a summary of the known gene-enzyme relationships is given.

Chromatography, Thin Layer↗

The photophysical properties of a julolidene-based molecular rotor.

The photophysical properties of 9-dicyanovinyljulolidine are sensitive to solvent viscosity but are little affected by changes in polarity. In fluid solution, the lifetime of the first-excited singlet state is very short and triplet state formation cannot be detected by laser flash photolysis. Decay of the excited singlet state is strongly activated and weak phosphorescence can be observed in a glassy matrix at 77 K. Temperature dependent 1H NMR studies indicate that the molecule undergoes slow internal rotation in solution, for which the activation energy has a value of ca. 35 kJ mol(-1). This process is unlikely to account for the poor fluorescence quantum yield found in fluid solution. Instead, it is considered that the target compound undergoes rapid rotation around the dicyanovinyl double bond from the excited singlet state. The rate of rotation depends weakly on the viscosity of the solvent in a range of linear alcohols at room temperature. This might represent the fact that the rotor is relatively small and can pack into cavities in the solvent structure. In glycerol, the rate of rotation is more sensitive to viscosity effects but a quite complex temperature dependence is observed in ethanol. Here, the rate is almost activationless in a glassy matrix and in fluid solution at high temperature but strongly activated at intermediate temperatures.

Electrochemistry↗

Biosynthesis of phenylalanine, tyrosine, 3-(3-carbocyphenyl) alanine and 3-(3-carbocy-4-hydroxyphenyl) alanine in higher plants. Examples of the transformation possibilities for chorismic acid.

14C-labelled shikimic acid and double labelled shikimic acid tritiated stereospicifically at C-6 are incorporated into 3-(3-carboxyphenyl) alanine, 3-(3-carboxy-4-hydroxyphenyl) alanine, phenylalanine, and tyrosine in Reseda lutea L., Reseda odorata L., Iris x Hollandica cv. Prof. Blauw, and Iris x hollandica cv. Wedgwood. The experiments with 14C-labelled shikimic acid confirm that the aromatic carboxyl groups and rings in 3-(3-carboxyphenyl) alanine and 3-(3-carbocy-4-hydroxyphenyl) alanine derive from the carbocyl group and ring in shikimic acid whereas the experiments with double labelled shikimic acid demonstrate that the pro-6S-hydrogen atom is retained and the pro-6R-hydrogen atom lost in the biosynthesis of 3-(3-carboxyphenyl) alanine, phenylalanine, and tyrosine in the plants used. 3H was located in the ortho-position in the aromatic rings of phenylalanine and tyrosine but in a position para to the alanine side chain of 3- (3-carboxyphenly) alanine. No 3H was found in 3- (3-carboxy-4-hydroxyphenyl) alanine. This supports a derivation of the last two compounds from chorismic acid via isochorismic acid, isoprephenic acid, and 3'-carboxyphenylpyruvic acid and 3'-carbocy-4'-hydroxyphenylphruvic acid. The 3H/14C ratio in 3-(3-carboxyphenyl) alanine was found higher than in the precursor used. This isotope effect must operate by competition between the pathways from isoprephenic acid to 3'-carbocyphenylpyruvic acid and to 3'-carbocy-4'- hydroxyphenylpyruvic acic. The proposed biosynthetic pathways for the two carboxy-substituted amino acids are in agreement with their distribution patterns in the plant kingdom and suggest that they may derive from minor changes of enzymes involved in the general pathways of aromatic biosynthesis.

Amino Acids↗