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PubMed1996

Hypolipidemic activity of 3-amino-1-(2,3,4-mononitro-, mono-, or dihalophenyl)propan-1-ones in rodents.

A series of 3-amino-1-(2,3,4-mononitro-, mono-, or dihalo-phenyl)propan-1-ones were synthesized and shown to be effective in lowering both serum cholesterol and triglyceride levels significantly in CF1 mice and Sprague-Dawley rats. All analogs showed better activity than the standard drugs, lovastatin and clofibrate, in reducing the serum cholesterol and triglyceride levels in mice at 8 mg/kg/day intraperitoneally. The best active analogs, 3-morpholino-1(3-nitrophenyl)propan-1-one (4) and 3-piperidino-1-(3-nitrophenyl)propan-1-one (5), exhibited 58% and 67% reduction of serum cholesterol levels, respectively, and 42% and 46% reduction of serum triglyceride levels, respectively, after 16 days of administration at 8 mg/kg/day intraperitoneally in CF1 mice. In Sprague-Dawley rats at 8 mg/kg/day oral administration, both compounds (4 and 5) significantly decreased the serum cholesterol and triglyceride levels. Rat tissue lipid levels were reduced significantly by compound 4, while less effects resulted from compound 5. The cholesterol and triglyceride levels in chylomicrons, VLDL, and LDL fractions were reduced by both analogs while the HDL cholesterol levels were significantly increased. Compound 5 was also effective in lowering serum cholesterol and triglyceride levels in hyperlipidemic mice, at 8 mg/kg/day intraperitoneally, but not effective in hyperlipidemic rats at 8 mg/kg/day orally. Cholesterol and triglyceride lowering effects of the agents were correlated with inhibition of the activities of liver acetyl CoA synthetase, HMG CoA reductase, phosphatidylate phosphohydrolase, and lipoprotein lipase, and with elevation of the activity of cholesterol ester hydrolase.

Animals↗
PubMed1994

Detection of propan-1,2-diol in neonatal brain by in vivo proton magnetic resonance spectroscopy.

Cerebral in vivo proton magnetic resonance spectroscopy of 13 newborn infants displaying seizures and receiving phenobarbitone, in one case supplemented by phenytoin, showed signals from propan-1,2-diol (the injection vehicle for both these anticonvulsants). Subsequent in vitro spectroscopy of cerebro spinal fluid (CSF) from one of these infants also showed signals from this substance. The estimated in vivo propan-1,2-diol concentration (approximately 3 mM) was less than that measured in the CSF sample (14.4 mM). These observations suggest that propan-1,2-diol may accumulate in cerebral tissue and misidentification of its signals in both in vivo and in vitro proton spectra may confuse diagnoses of metabolic or other disorders.

Brain Chemistry↗
PubMed2000

Tyr115, gln165 and trp209 contribute to the 1, 2-epoxy-3-(p-nitrophenoxy)propane-conjugating activity of glutathione S-transferase cGSTM1-1.

We investigated the epoxidase activity of a class mu glutathione S-transferase (cGSTM1-1), using 1,2-epoxy-3-(p-nitrophenoxy)propane (EPNP) as substrate. Trp209 on the C-terminal tail, Arg107 on the alpha4 helix, Asp161 and Gln165 on the alpha6 helix of cGSTM1-1 were selected for mutagenesis and kinetic studies. A hydrophobic side-chain at residue 209 is needed for the epoxidase activity of cGSTM1-1. Replacing Trp209 with histidine, isoleucine or proline resulted in a fivefold to 28-fold decrease in the k(cat)(app) of the enzyme, while a modest 25 % decrease in the k(cat)(app) was observed for the W209F mutant. The rGSTM1-1 enzyme has serine at the correponding position. The k(cat)(app) of the S209W mutant is 2. 5-fold higher than that of the wild-type rGSTM1-1. A charged residue is needed at position 107 of cGSTM1-1. The K(m)(app)(GSH) of the R107L mutant is 38-fold lower than that of the wild-type enzyme. On the contrary, the R107E mutant has a K(m)(app)(GSH) and a k(cat)(app) that are 11-fold and 35 % lower than those of the wild-type cGSTM1-1. The substitutions of Gln165 with Glu or Leu have minimal effect on the affinity of the mutants towards GSH or EPNP. However, a discernible reduction in k(cat)(app) was observed. Asp161 is involved in maintaining the structural integrity of the enzyme. The K(m)(app)(GSH) of the D161L mutant is 616-fold higher than that of the wild-type enzyme. In the hydrogen/deuterium exchange experiments, this mutant has the highest level of deuteration among all the proteins tested. We also elucidated the structure of cGSTM1-1 co-crystallized with the glutathionyl-conjugated 1, 2-epoxy-3-(p-nitrophenoxy)propane (EPNP) at 2.8 A resolution. The product found in the active site was 1-hydroxy-2-(S-glutathionyl)-3-(p-nitrophenoxy)propane, instead of the conventional 2-hydroxy isomer. The EPNP moiety orients towards Arg107 and Gln165 in dimer AB, and protrudes into a hydrophobic region formed by the loop connecting beta1 and alpha1 and part of the C-terminal tail in dimer CD. The phenoxyl ring forms strong ring stacking with the Trp209 side-chain in dimer CD. We hypothesize that these two conformations represent the EPNP moiety close to the initial and final stages of the reaction mechanism, respectively.

Amino Acid Substitution↗
PubMed2006

Lipase-mediated transformation of vegetable oils into biodiesel using propan-2-ol as acyl acceptor.

Propan-2-ol was used as an acyl acceptor for immobilized lipase-catalyzed preparation of biodiesel. The optimum conditions for transesterification of crude jatropha (Jatropha curcas), karanj (Pongamia pinnata) and sunflower (Helianthus annuus) oils were 10% Novozym-435 (immobilized Candida antarctica lipase B) based on oil weight, alcohol to oil molar ratio of 4:1 at 50 degrees C for 8 h. The maximum conversions achieved using propan-2-ol were 92.8, 91.7 and 93.4% from crude jatropha, karanj and sunflower oils, respectively. Reusability of the lipase was maintained over 12 repeated cycles with propan-2-ol while it reached to zero by 7(th) cycle when methanol was used as an acyl acceptor, under standard reaction conditions.

2-Propanol↗
PubMed1991

Study of polymeric systems based on 2,2 bis-4(2-hydroxy-3-methacryloyl-oxypropoxy) phenyl propane.

2,2 bis-4(2-hydroxy-3-methacryloyloxypropoxy) phenyl propane is the basic monomer for a large number of proprietary dental composite filling materials. In this paper, studies have been made of its copolymers with various comonomers. 2,2 bis-4(2-hydroxy-3-methacryloyloxypropoxy) phenyl propane--tetrahydrofurfuryl methacrylate copolymers, at about the 95/5% v/v level, showed an enhanced modulus over that of the test material itself, to give a Young's modulus of -4.8 GPa. This reflected an enhanced activation energy of the glass transition temperature, indicating a very specific free volume effect of the diluent monomer. Further studies 2,2 bis-4(2-hydroxy-3-methacryloyloxypropoxy) phenyl propane-tetrahydrofurfuryl methacrylate room temperature polymerized copolymers showed that enhanced modulus could be achieved by including in the system small amounts of inhibitor; 0.3% v/v 2,6 di-tertiary butyl phenol elevated the Young's modulus of a benzoyl peroxide--NN-dihydroxy ethyl p-toluidine cured system from 3.1 to 3.6 GPa. Such resins may be useful in improved dental fissure sealants and composite filling materials.

Benzoyl Peroxide↗
PubMed1991

The effect of propane-diols on the intestinal uptake of nutrients and brush border membrane enzymes in the rat.

The effect on rats of oral doses (38.66 mM/kg body wt) of propane-1,2-diol (PD) administered daily for 10 (Group 1), 20 (Group 2), and 30 days (Group 3) was investigated. Weight gain was initially retarded (P less than 0.05) in Group 1, but was later reversed and elevated significantly (P less than 0.05) in Groups 2 and 3 as compared with their respective controls receiving an equal volume of saline. PD showed a tendency toward enhancing the activities of various enzymes involved in terminal digestion, with the significant effect exerted in few groups on sucrase (P less than 0.05), lactase (P less than 0.05), and gamma-glutamyl transpeptidase (P less than 0.05) when compared with the respective controls. Absorption of D-glucose, glycine, L-aspartic acid, L-lysine, and calcium was elevated and was especially significant in Groups 2 and 3 (P less than 0.001). The structural integrity of the jejunal surface was retained for the most part. A similar examination of the effects of PD was also carried out in vitro to ascertain whether PD itself or its metabolites are involved in its action. The in vitro effects of propane-1,2-diol were compared with those of the more toxic compound propane-1,3-diol. The former exerted greater inhibitory action on the activities of the disaccharidases. The degree of inhibition was in the order sucrase much greater than lactase greater than maltase. The kinetic data revealed that inhibition by 1,2-diol in native and detergent solubilized sucrase is noncompetitive, with Ki values in the range of 0.35-0.41 M. The two diols did not alter the nutrient transport in the brush border membrane vesicles. The present work on rats indicates that PD may influence the intestinal digestive and absorptive functions in vivo and that this in vivo effect of PD is different from that observed in vitro suggesting that the nutritional and toxicological effect of PD may be mediated by different mechanisms.

Administration, Oral↗
PubMed2001

Membrane permeability of human oocytes in the presence of the cryoprotectant propane-1,2-diol.

OBJECTIVE: To determine the permeability of unfertilized human oocytes to water and the cryoprotectant propane-1,2-diol over a range of temperatures and to use these data to predict osmotic responses under given conditions. DESIGN: Laboratory-based study. SETTING: Teaching hospital. PATIENT(S): Infertility patients donating unfertilized oocytes in excess of those required for treatment. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Water and cryoprotectant permeability were determined from measurements of oocyte volume excursions on exposure to 1.5 M propane-1,2-diol at 30 degrees C, 24 degrees C, and 10 degrees C. RESULT(S): Permeability of human oocytes to water and cryoprotectant increased as temperature increased. The predicted response of oocytes, based on these data, closely matched the measured response of an oocyte on exposure to a widely used method for addition of cryoprotectant before freezing. CONCLUSION(S): Commonly used cryopreservation protocols involving slow cooling in the presence of propane-1,2-diol cause potentially damaging excursions in cell volume on exposure to cryoprotectant. Modifications that can be expected to reduce cell volume excursions, based on oocyte permeability data, are suggested.

Cell Membrane Permeability↗
PubMed1996

In vitro wear, hardness, and conversion of diacetyl-containing and propanal-containing resin materials.

OBJECTIVES: This study was conducted to determine the effect of diacetyl or propanal activities: 1) on the in vitro wear of 22 experimental resin composites; and 2) on the Wallace indentation hardness of the unfilled resins. The objective was to examine the correlation between wear, hardness, and quantity of remaining double bonds (determined previously). METHODS: Diacetyl or propanal agents were added in varying concentrations to monomer mixtures. The resins were made light-curing and those used for measurement of wear were loaded with filter. The results were analyzed by ANOVA and Newman-Keuls' multiple range tests. RESULTS: In the composite systems, adding diacetyl or propanal resulted in decreased in vitro wear. The quantity of remaining double bonds in the dental polymers with these additives was also reduced. Their effect on Wallace indentation depth was less clear-cut. Low concentrations of additives decreased indentation depth of the unfilled materials, whereas high concentrations increased indentation depth. If it assumed that differences in the polymer have a major influence on the wear when the filter content and particle matrix interface are kept constant, then the hardness data on the unfilled resin can be used to correlate property changes of the polymer in the composite. A three-dimensional regression analysis found that in vitro wear decreased with decreasing Wallace indentation depth and decreasing quantity of remaining double bonds. SIGNIFICANCE: Addition of diketone or monoaldehyde to resin monomers may provide a means of increasing wear resistance of composites and allow their use in stress-bearing areas.

Aldehydes↗
PubMed2001

New 3-[4-(aryl)piperazin-1-yl]-1-(benzo[b]thiophen-3-yl)propane derivatives with dual action at 5-HT1A serotonin receptors and serotonin transporter as a new class of antidepressants.

A series of new 3-[4-(aryl)piperazin-1-yl]-1-(benzo[b]thiophen-3-yl)propane derivatives were synthesized in an attempt to find a new class of antidepressant drugs with dual activity at 5-HT1A serotonin receptors and serotonin transporter. Title compounds were evaluated for in vitro activity on 5-HT1A receptor and 5-HT transporter. They show high nanomolar affinity for both activities, and in particular, compounds 1-(5-chlorobenzo[b]thiophen-3-yl)-3-[4-(2-methoxyphenyl)piperazin-1-yl]propan-1-ol (7) and 1-(5-fluorobenzo[b]thiophen-3-yl)-3-[4-(2-methoxyphenyl)piperazin-1-yl]propan-1-ol (8) show values (nM) of K(i)=30 and 2.3 for 5-HT1A receptors and K(i)=30 and 12 for serotonin transporters, respectively. In GTPgammaS binding assays, compound 8 revealed antagonist properties to 5-HT1A receptors. Such a pharmacological profile could lead to potent antidepressant agents with new dual mechanism of action.

Animals↗
PubMed2006

Periodic density functional theory study of propane oxidative dehydrogenation over V2O5(001) surface.

The oxidative dehydrogenation (ODH) of propane on single-crystal V(2)O(5)(001) is studied by periodic density functional theory (DFT) calculations. The energetics and pathways for the propane to propene conversion are determined. We show that (i) the C-H bond of propane can be activated by both the terminal and the bridging lattice O atoms on the surface with similar activation energies. At the terminal O site both the radical and the oxo-insertion pathways are likely for the C-H bond activation, while only the oxo-insertion mechanism is feasible at the bridging O site. (ii) Compared to that at the terminal O site, the propene production from the propoxide at the bridging O site is much easier due to the weaker binding of propoxide at the bridging O. It is concluded that single-crystal V(2)O(5)(001) is not a good catalyst due to the terminal O being too active to release propene. It is expected that an efficient catalyst for the ODH reaction has to make a compromise between the ability to activate the C-H bond and the ability to release propene.

Journal Article↗
PubMed1979

Cardioselectivity of beta-adrenoceptor blocking agents 1. 1-[(4-Hydroxyphenethyl)amino]-3-(aryloxy)propan-2-ols.

A series of 1-[(4-hydroxyphenethyl)amino]-3-(aryloxy)propan-2-ols was synthesized together with several 1-[(3,4-dimethoxyphenethyl)amino]-3-(aryloxy)propan-2-ols. Their affinity to beta 1- and beta-2-adrenoceptors was determined and compared with the affinity of known beta-blockers. We were able to confirm the substantial cardioselectivity of 1-(3,4-dimethoxyphenethyl)-3-[(4-substituted aryl)oxy]propan-2-ols when compared to those with a 1-(4-hydroxyphenethyl) group. An increase in the size of the 4 substitutent of the 3-(aryloxy) moiety to caproamido leads to a substantially higher affinity for the beta 1--adrenoceptor of rat ventricular muscle in the presence of the 3,4-dimethoxyphenethyl than in the presence of the 4-hydroxyphenethyl or isopropyl group; this combination also gave the highest cardioselectivity.

Adrenergic beta-Antagonists↗
PubMed2005

Roles of surface Te, Nb, and Sb oxides in propane oxidation to acrylic acid over bulk orthorhombic Mo-V-O phase.

The outermost surfaces and subsurface layers of the orthorhombic (M1) Mo-V-O catalysts promoted with Te, Nb, and Sb oxide species at submonolayer surface coverage were examined by low-energy ion scattering (LEIS). This study indicated that the Nb oxide species was preferentially located at the topmost surface, while the subsurface Te and Sb concentrations declined gradually into the bulk. Although the original Mo-V-O catalyst was essentially unselective in propane oxidation to acrylic acid, significant improvement in the selectivity to acrylic acid was observed when Te, Nb, and Sb oxides were present as the surface species at submonolayer coverage. These findings further suggested that the formation of the surface V-O-M bonds (M = Nb, Te, or Sb) was highly beneficial for both the activity and selectivity of the orthorhombic Mo-V-O catalysts in propane oxidation to acrylic acid. The highest selectivity was observed when both Nb and Te (or Sb) oxide species were present at the surface. The selectivity trends established for the surface-promoted Mo-V-O catalyst parallel those found previously for the corresponding bulk Mo-V-M-O catalysts. These results further indicated that the introduction of surface metal oxide species is a highly promising method to prepare well-defined model catalysts for studies of the structure-activity/selectivity relationships as well as optimize the catalytic performance of the bulk mixed Mo-V-M-O catalysts for selective (amm)oxidation of propane.

Journal Article↗
PubMed2005

Selective catalytic reduction of NO by propane over CoO(x)/Al2O3: an investigation of the surface reactions using in situ infrared spectroscopy.

The partial oxidation of propane and the mechanism of the selective catalytic reduction (SCR) of NO by C3H8 over CoO(x)/Al2O3 catalysts were investigated using in situ infrared spectroscopy. Emphases are placed on the formation and reactivity of surface oxygenates during the SCR reaction. The SCR reaction starts with partial oxidation of propane to adsorbed acetate and formate. Impregnation of cobalt onto alumina greatly enhanced this reaction. The as-formed acetate acts as an efficient reductant for NO reduction. Surface nitrates (nitrites) are also reactive to propane and to oxygenates generated from C3H8 + O2 reaction. Surface -NCO species are formed over CoO(x)/Al2O3 catalysts. These nitrogen containing organic species are believed to be the direct intermediates in the final formation of N2. On the basis of these investigations, a proposed reaction mechanism explains the formation and roles of all intermediates detected by IR spectroscopy in this study.

Journal Article↗
PubMed2006

Photoelectron imaging of propanal by resonant multiphoton ionization via the 3s Rydberg state.

We report the conformationally- and vibrationally-selected photoelectron spectroscopy of propanal obtained by resonance-enhanced multiphoton ionization (REMPI) using photoelectron imaging. These photoelectron spectra, employing (2 + 1) ionization via the (n, 3s) Rydberg transitions in the range from 365 to 371 nm, confirm that there are two stable conformer origins in the lowest ionic state, the cis conformer with a co-planar CCCO geometry and a gauche conformer with a approximately 119 degrees CCCO dihedral angle. From ab initio calculations at the B3LYP/6-311++G** level, we find the gauche conformer is slightly more stable, with the energy difference between two conformers determined to be only 65 cm(-1). In our photoelectron spectra, the vertical ionization potential (IP) for the cis conformer of propanal was then determined to be 9.999 (+/-0.003) eV, while that of the gauche conformer of propanal was estimated to be 9.944 eV. A long vibrational progression in the in-plane CCCO deformation vibrational mode, v, for the cis conformer is systematically observed in all photoelectron spectra in which this mode is excited, suggesting that the geometry of the ground ionic state is significantly different from that of the 3s Rydberg state, particularly along the v(15) coordinates.

Aldehydes↗
PubMed2006

Ceramic microreactors for on-site hydrogen production from high temperature steam reforming of propane.

The steam reforming of hydrocarbon fuels is a promising method for the production of hydrogen for portable electrical power sources. A suitable reactor for this application, however, must be compatible with temperatures above 800 degrees C to avoid coking of the catalytic structures during the reforming process. Here, ceramic microreactors comprising high surface area, tailored macroporous SiC porous monoliths coated with ruthenium (Ru) catalyst and integrated within high-density alumina reactor housings were used for the steam reforming of propane into hydrogen at temperatures between 800 and 1000 degrees C. We characterized these microreactors by studying C3H8 conversion, H2 selectivity, and product stream composition as a function of the total inlet flow rate, steam-to-carbon ratio (S/C), and temperature. As much as 18.2 sccm H2, or 3.3 x 104 sccm H2 per cm3 of monolith volume, was obtained from a 3.5 sccm entering stream of C3H8 at a S/C of 1.095 and temperatures greater than 900 degrees C. Operating at a S/C close to 1 reduces the energy required to heat excess steam to the reaction temperature and improves the overall thermal efficiency of the fuel processor. Kinetic analysis using a power law model showed reaction orders of 0.50 and -0.23 with respect to propane and steam, respectively, indicating that the rate limiting step in the steam reforming reaction is the dissociative adsorption of propane on the Ru catalyst. The performance of the microreactor was not affected after exposure to more than 15 thermal cycles at temperatures as high as 1000 degrees C, and no catalyst deactivation was observed after more than 120 h of continuous operation at 800 degrees C, making these ceramic microreactors promising for efficient on-site hydrogen production from hydrocarbons for use in polymer electrolyte membrane (PEM) fuel cells.

Journal Article↗
PubMed1975

Effect of a single oral dose of methanol, ethanol and propan-2-ol on the hepatic microsomal metabolism of foreign compounds in the rat.

Methanol and ethanol administered to rats as a single oral dose increased aniline hydroxylation by the hepatic microsomal fraction by a maximum of 169 and 66% respectively, whereas aminopyrine demethylation was inhibited by 51 and 61%. The concentration of microsomal cytochrome P-450, and the activities of NADPH-cytochrome c reductase and NADPH-cytochrome P-450 reductase were unchanged. Propan-2-ol, administered as a single oral dose, increased microsomal aniline hydroxylation by 165% and increased aminopyrine demethylation by 83%. The concentration of cytochrome P-450 was unchanged whereas NADPH-cytochrome c reductase and NADPH-cytochrome P-450 reductase were both increased by 38%. Methanol, ethanol and propan-2-ol administration resulted in a decreased type I spectral change but had no effect on the reverse type I spectral change. Methanol administration decreased the type II spectral change whereas ethanol and propan-2-ol had no effect. Cycloheximide blocked the increases in aniline hydroxylation and aminopyrine demethylation but could not completely prevent the decreases in aminopyrine demethylation. The increases in aniline hydroxylation were due to an increase in V, but Km was unchanged. The ability of acetone to enhance and compound SKF 525A to inhibit microsomal aniline hydroxylation was decreased by the administration of all three alcohols. The decrease in the metabolism of aminopyrine may result from a decrease in the binding to the type I site with a consequent failure of aminopyrine to stimulate the reduction of cytochrome P-450. Methanol administration may lead to an increase in aniline hydroxylation because of a failure of aniline to inhibit cytochrome P-450 reduction.

1-Propanol↗
PubMed2002

Rotational dynamics of propane in Na-Y zeolite: a molecular dynamics and quasielastic neutron-scattering study.

We report results from molecular dynamics (MD) simulations and quasielastic neutron-scattering (QENS) measurements on the rotational dynamics of propane in Na-Y zeolite at room temperature with a loading of four molecules per alpha cage. Rotational part of the intermediate scattering function F(Q,t) obtained from the MD simulation suggests that rotational motion is faster relative to the translational motion. Various rotational models fitted to the MD data suggest that rotation is isotropic. It is found that the hydrogen atoms lie, on the average, on a sphere of radius 1.88+/-0.05 A, which is also the average distance of the hydrogen atoms from the center of mass of the propane molecule. Results from QENS measurements are in excellent agreement with those obtained from MD, suggesting that the intermolecular potential employed in the MD simulation provides a realistic description of propane motion within faujasite. The rotational diffusion constant D(R) is 1.05+/-0.09 x 10(12) sec(-1) from the QENS data, which may be compared with that obtained from the MD data (0.82+/-0.05 x 10(12) sec(-1)).

Journal Article↗
PubMed1969

Ethylene production from propanal.

Tracer studies using a model system consisting of Cu(2+) and ascorbate indicate that carbons 2 and 3 of propanal are converted to ethylene, and carbon 1 is converted to formic acid and CO(2). A mechanism accounting for this reaction is described. In apple tissue, methionine but not propanal is readily incorporated into ethylene. It is therefore concluded that propanal is not a precursor of ethylene in this fruit.

Journal Article↗