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At least 487 records · Page 27Linked to original sources
PubMed1989

Determination of antileukemic diimidazolinyl compounds in plasma of experimental animals by high-performance liquid chromatography.

A method is reported for the determination of the fluorescent, antileukemic diimidazolinyl compounds 261/96(1). 253/152(2) and 272/131(3) in plasma. HPLC is performed on a RP-2 10 microns column with a mobile phase of methanol/water (1:1, v/v), to which 0.005 mol/l octanesulfonic acid sodium and 0.003 mol/l dimethyloctylamine are added. Samples are prepared by precipitation of plasma proteins with a mixture of methanol-70% perchloric acid. The assay is linear up to 750 ng/ml for all compounds with limits of determination of 4 ng/ml, 2 ng/ml and 0.5 ng/ml for compounds 1, 2 and 3, respectively. Coefficients of variation are below 10 percent at all concentrations studied.

Antineoplastic Agents↗
PubMed1993

Divinyl ethers and hydroxy fatty acids from three species of Laminaria (brown algae).

Three species of brown algae, Laminaria sinclairii, L. saccharina and L. setchellii, have been investigated for the presence of oxylipins. From one, L. sinclairii, three new divinyl ether fatty acids have been characterized as methyl ester derivatives (methyl 12-[1'(Z),3'(Z)-hexadienyloxy]-6(Z), 9(Z),11(E)-dodecatrienoate, methyl 12-[1'(Z),3'(Z)-hexadienyloxy]-9(Z), 11(E)-dodecadienoate, and methyl 14-[1'(Z),3'(Z)-hexadienyloxy]- 5(Z),8(Z),11(Z),13(E)-tetradecatetraenoate) by a variety of spectroscopic methods. In addition, one new [13(S)-hydroxy-6(Z),9(Z),11(E),15(Z)-octadecatetraenoic acid] and four known monohydroxy polyunsaturated fatty acids have been isolated from all three species as their methyl ester derivatives. The occurrence of these compounds in brown algae strongly suggests that these organisms possess an active lipoxygenase(s) with omega 6 specificity.

Fatty Acids↗
PubMed2001

[Synthesis and biological activity of 2-[(substituted phenyl)vinyl] indole derivatives].

AIM: To synthesize derivatives of 2-[substituted phenyl)vinyl] indole and find compounds with biological activities by screening in vitro. METHODS: Twenty-one compounds of 2-[(substituted phenyl) vinyl] indole were synthesized by reduction, oxidation and Witting reaction. MS, 1HNMR and elemental analysis were used to determine the structures of the new compounds. RESULTS: These compounds are new ones. CONCLUSION: Six compounds (3, 9, 11, 13, 18 and 20) showed effects on some different receptors, such as alpha 2, D2 and H1, and is worth further studying.

Animals↗
PubMed1993

Synthesis of A-ring fluorinated derivatives of (17 alpha,20E/Z)-[125I]iodovinylestradiols: effect on receptor binding and receptor-mediated target tissue uptake.

We have prepared a series of 2- and 4-fluoro derivatives of the isomeric (17 alpha,20E)- and (17 alpha, 20Z)iodovinylestradiols (IVE2) and also the analogs substituted with either a 7 alpha-methyl (7 alpha-Me-IVE2) or 11 beta-methoxy group (11 beta-OMe-IVE2) and evaluated their in vitro and in vivo properties. Electrophilic substitution of the estrone derivatives with N-fluoropyridinium salt gave the 2- and 4-fluoro analogs which were subsequently converted to the 17 alpha-ethynyl derivatives. The tributylstannyl intermediates were obtained from the corresponding 17 alpha-ethynyl analogs using azobisisobutyronitrile or triethylborane as catalyst. All 12 products were also prepared as their no-carrier-added [125I]iodovinyl analogs via destannylation of the tributylstannyl precursors. Binding affinity for the estrogen receptor (ER) was in general higher for the 4-F derivatives as compared to the 2-F derivatives, while the 20Z isomers of the same compounds showed somewhat higher ER binding affinity as compared to the 20E isomers. The combination of an A-ring fluoro and 7 alpha- or 11 beta-substituent decreased ER binding affinity. Substitution of a fluoro atom at C-4 on either the 17 alpha-ethynylestradiol or isomeric 17 alpha-IVE2 enhanced the affinity of the parent molecule for the ER. A-ring fluorination of all other analogues tested had no effect or depressed ER binding affinity. Varying incubation conditions showed substantial differences in ER binding kinetics between the 20E and 20Z isomers. Tissue distribution in immature female rats showed that the highest uterus uptake and uterus to blood/nontarget ratios in the IVE2 series were obtained with the 4-F-(17 alpha,20Z)IVE2 isomer. The combination of A-ring fluoro and 7 alpha- or 11 beta-substitution decreased uterus uptake but had little or no effect on uterus to blood/nontarget ratios. The highest uterus to blood ratios were observed for the 4-F-(17 alpha,20E)11 beta-OMe-IVE2 (75 at 6 h and 125 at 12 h pi) reflecting rapid blood clearance and in vivo stability, as confirmed by the low levels of thyroid radioactivity. The lack of correlation between ER binding affinities and uterus uptake, and/or uptake ratios, suggests that other factors, including nonspecific binding and metabolic processes, also are involved in the tissue localization process. Our data suggest that 4-F substitution onto (17 alpha,20Z)IVE2 and (17 alpha,20E)11 beta-OMe-IVE2 enhances the potential of these compounds to function as SPECT imaging agents of ER-rich tissues.

Animals↗
PubMed1977

Antagonists of vitamin B6. Simultaneous and stepwise modification of the 2 and 4 positions.

Methods for the simultaneous and stepwise modification of the 2 and 4 positions of vitamin B6 have been devloped and have been applied to the synthesis of several analogues of this vitamin. 3,alpha5-O-Dibenzylpyridoxol was converted to its N-oxide and was rearranged to an alpha2-hydroxy derivative with (CF3CO)2O. The 2,4-bis(hydroxymethyl) intermediate was oxidized (MnO2) to the 2,4-dialdehyde, which was converted by a Wittig reaction with triphenylmethylphosphorane to the 2,4-divinyl derivative. Removal of the benzyl groups with acid gave the 2,4-divinylpyridioxol analogue, which was phosphorylated in the 5' position to give the cofactor analogue. The 2-CH3 in the known vitamin B6 antagonists, 4-deoxypyridoxol and 4-vinylpyridoxal, was similarly modified to CH2OH, CHO, and CH = CH2. Modifications of the 2 position in the vitamin B6 antagonists are expected to be associated with changes in selectivity for enzymes in various tissues without a concomitant loss of biological activity, because of the well-established bulk tolerance in this position. Active analogues are expected to undergo, in vivo 5-phosphorylation, which is probably a prerequisite for their antagonist activity. Some of the compounds (e.g., the 2,4-divinyl analogue) have substantial growth-inhibitory activity for cultured mouse mammary adenocarcinoma. In contrast to that of the parent compounds, this activity was only partially reversed by pyridoxal.

Adenocarcinoma↗
PubMed2006

Vinyldiazolactone as a vinylcarbene precursor: Highly selective C-H insertion and cyclopropanation reactions.

Vinylcarbenes are versatile synthetic intermediates, capable of asymmetric cyclopropanation and insertion into unactivated C-H bonds. The vinyldiazolactone precursor to the metal vinylcarbene possesses superior stability in comparison to previously known vinyldiazoacetates and, for the first time, allows the use of Z-vinylcarbenes in asymmetric C-H insertion and cyclopropanation reactions. Dirhodium azetidinone ligated compounds are optimal catalysts. Cyclopropanation coupled with the Cope rearrangement provides access to trans-3,4-disubstituted hydroazulenes.

Alkenes↗
PubMed1995

Factors affecting the concentration of compound A resulting from the degradation of sevoflurane by soda lime and Baralyme in a standard anesthetic circuit.

Carbon dioxide absorbents, such as soda lime and Baralyme brand absorbent, convert sevoflurane to CF2 = C(CF3)OCH2F, a vinyl ether called "Compound A," whose toxicity raises concerns regarding the safety of sevoflurane in rebreathing circuits. Because an increased inflow rate to an anesthetic circuit decreases rebreathing, we assumed that an increased rate would proportionately decrease the concentration of Compound A. In the present report, we measured the Compound A concentration resulting from the action of wet (standard) soda lime and wet (standard) Baralyme on 2% sevoflurane in a model anesthetic circuit, using inflow rates (0.5, 1.0, 2.0, 4.0, and 6.0 L/min), ventilations (5 and 10 L/min), and carbon dioxide production/removal (200 and 400 mL/min) found in clinical practice. An increase in inflow rate decreased Compound A concentration to lower levels as inflow rate approached minute ventilation. At lower inflow rates, increasing duration of sevoflurane inflow increased the concentration of Compound A, a finding consistent with a progressive increase in absorbent temperature from absorption of carbon dioxide and consequently greater sevoflurane degradation. There was no material difference between Baralyme and soda lime in the concentrations of Compound A produced at a particular inflow rate. An increase in ventilation increased the concentration of Compound A, having a much greater effect at high rather than low inflow rates. An increase in amount of carbon dioxide absorbed also increased the concentration of Compound A. We conclude that inflow rate, ventilation, and carbon dioxide production are major determinants of the concentration of Compound A.

Absorption↗
PubMed1999

Divinyl ether fatty acid synthesis in late blight-diseased potato leaves.

We conducted a study of the patterns and dynamics of oxidized fatty acid derivatives (oxylipins) in potato leaves infected with the late-blight pathogen Phytophthora infestans. Two 18-carbon divinyl ether fatty acids, colneleic acid and colnelenic acid, accumulated during disease development. To date, there are no reports that such compounds have been detected in higher plants. The divinyl ether fatty acids accumulate more rapidly in potato cultivar Matilda (a cultivar with increased resistance to late blight) than in cultivar Bintje, a susceptible cultivar. Colnelenic acid reached levels of up to approximately 24 nmol (7 microgram) per g fresh weight of tissue in infected leaves. By contrast, levels of members of the jasmonic acid family did not change significantly during pathogenesis. The divinyl ethers also accumulated during the incompatible interaction of tobacco with tobacco mosaic virus. Colneleic and colnelenic acids were found to be inhibitory to P. infestans, suggesting a function in plant defense for divinyl ethers, which are unstable compounds rarely encountered in biological systems.

Ethers↗
PubMed2006

On the relationship between the activity and structure of PEG-alpha-chymotrypsin conjugates in organic solvents.

Enzymes are attractive catalysts for the production of optically active compounds in organic solvents. However, their often low catalytic activity in such applications hampers their practical use. To overcome this, we investigated the effectiveness of the covalent modification of alpha-chymotrypsin with methoxy poly(ethylene glycol) (PEG) with a Mw of 5,000 to enhance its activity. The model transesterification reaction between sec-phenethyl alcohol and vinyl butyrate in various neat dry organic solvents and at a controlled water activity of 0.008 in two solvents was employed to measure the effect of PEGylation on activity and enantioselectivity. Synthesis conditions were varied to obtain various conjugates with average molar ratios of PEG-to-chymotrypsin ranging from ca. 1 to 7. While the enantioselectivity increased only modestly from ca. 4.4 to 6.1 when averaging results in all solvents, PEG was very efficient in increasing the activity of alpha-chymotrypsin up to more than 400-fold compared to that of the powder lyophilized from buffer alone. The activity increase was more pronounced in apolar than in polar organic solvents and also depended on the amount of PEG bound to the enzyme. For example, the activity of the modified enzyme towards the most reactive "S" enantiomer in octane increased 440-fold but increasing the molar ratio of PEG-to-enzyme from 1.1 to 7.1 resulted in a more than twofold decrease in enzyme activity. Controlling the water activity did not prevent the drop in activity. To investigate the possible origin of the activity changes, Fourier transform infrared (FTIR) spectroscopy experiments were conducted. It was found that PEGylation reduced lyophilization-induced structural perturbations, but exposure to the organic solvents caused structural perturbations. These perturbations were more pronounced in polar than in apolar solvents. The pronounced activity drop in polar solvents at increasing PEG-modification levels correlated with an increasing level of solvent-induced structural perturbations. This correlation was less pronounced in apolar solvents where both, activity drop and structural perturbations, were less pronounced at increasing PEGylation levels. In summary, PEG-modified alpha-chymotrypsin might be an interesting system to catalyze reactions, particularly in apolar organic solvents.

Alcohols↗
PubMed2000

Nicotine and 3-ethenylpyridine concentrations as markers for environmental tobacco smoke in restaurants.

The Finnish Tobacco Act has restricted smoking in public places since 1976, and in 1994 the Act was amended to include workplaces as well. In 2000, the Tobacco Act will be expanded further to restaurants. In Finland, the exposure of clients and employees to the vapor phase environmental tobacco smoke (ETS) in restaurants has not been systematically studied before by measuring ETS markers in indoor air. However, in these establishments the concentrations of ETS are expected to be much higher than in other workplaces. Gaseous nicotine and 3-ethenylpyridine were used as indicators of ETS in three different types of restaurants. Mean concentrations of nicotine ranged from 1.4-42.2 micrograms/m3 and 3-ethenylpyridine 1.4-6.3 micrograms/m3. In addition, concentrations of total volatile organic compounds (TVOC), CO and CO2 were measured and concentrations were 183-2215 micrograms/m3, 0.9-3.1 mg/m3 and 600-880 ppm, respectively. The concentrations of ETS markers were highest in discos and nightclubs and lowest in restaurants. The concentrations of total volatile organic compounds were highest in discos and nightclubs, especially when smoke generators were used.

Carcinogens↗