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PubMed2002

Lactone enol cation-radicals: gas-phase generation, structure, energetics, and reactivity of the ionized enol of butane-4-lactone.

The cation-radical of 2-hydroxyoxol-2-ene (1(+*)) represents the first lactone enol ion whose structure and gas-phase ion chemistry have been studied by experiment and theory. Ion 1(+*) was generated by the McLafferty rearrangement in ionized 2-acetylbutane-4-lactone and characterized by accurate mass measurements, isotope labeling, metastable ion and collisionally activated dissociation (CAD) spectra. Metastable 1(+*) undergoes competitive losses of H-4 and CO that show interesting deuterium and (13)C isotope effects. The elimination of CO from metastable 1(+*) shows a bimodal distribution of kinetic energy release and produces (*)CH(2)CH(2)CHdbond;OH(+) (14(+*)) and CH(3)CHdbond;CHOH(+*) (15(+*)) in ratios which are subject to deuterium isotope effects. Ab initio calculations at the G2(MP2) level of theory show that 1(+*) is 105 kJ mol(-1) more stable than its oxo form, [butane-4-lactone](+*)(2(+*)). The elimination of CO from 1(+*) involves multiple isomerizations by hydrogen migrations and proceeds through ion-molecule complexes of CO with 14(+*) and 15(+*). In addition, CO is calculated to catalyze an exothermic isomerization 14(+*) --> 15(+*) in the ion-molecule complexes. Multiple consecutive hydrogen migrations in metastable 1(+*), as modeled by RRKM calculations on the G2(MP2) potential energy surface, explain the unusual deuterium kinetic isotope effects on the CO elimination.

Journal Article↗
PubMed2001

Jet-Cooled Multiphoton Ionization Spectroscopy of the iso-Butanal 3s<--n Rydberg Transition.

We report the results of a study on the vibrational structure in the (n, 3s) Rydberg state of iso-butanal, carried out via 2+1 multiphoton ionization spectroscopy in a supersonic expansion. Spectra were recorded for both the normal species, (CH(3))(2)CHCHO, and the deuterated isotopomer, (CH(3))(2)CDCHO. The spectra show a complicated vibrational pattern attributable to the gauche (C(1)) conformer which is known to be 250 cm(-1) lower in energy than the more symmetric trans (C(s)) conformer. The spectra are dominated by the low-frequency formyl torsion which appears in combination with the two methyl torsions (in-phase and out-of-phase) and with several skeletal modes. Vibrational assignments have been aided by ab initio calculations of the (n, 3s) Rydberg state. Copyright 2001 Academic Press.

Journal Article↗
PubMed1977

Behavioral comparisons of R-2-amino-1-(2,5-dimethoxy-4-methylphenyl) butane (BL-3912A) with R-DOM and S-amphetamine.

The behavioral effects of R-2-amino-1-(2,5-dimethoxy-4-methylphenyl) butane or BL-3912A were compared with those of S-Amphetamine and R-DOM. BL-3912A facilitated acquisition of shuttle box responding by rats without increasing noncontingent intertrial (ITI) activity, while S-Amphetamine increased both avoidance and ITI responding. R-DOM had a biphasic effect on avoidance responding, increasing it at low doses and disrupting at higher doses. At doses that facilitated shuttle box responding, BL-3912A had no effect on unacclimated motor activity of rats nor on the rate of continuous avoidance responding by rats. S-Amphetamine increased the frequency of both motor activity and operant avoidance responding, while R-DOM decreased motor activity and increased operant avoidance responding. By facilitating avoidance behavior without increasing othermeasures of psychomotor activity, BL-3912A represents a unique psychopharmacological agent clearly different from R-DOM and S-Amphetamine.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗
PubMed1981

Modification of functional arginine residues in purified bovine testicular hyaluronidase with butane-2, 3-dione.

Purified bovine testicular hyaluronidase (hyaluronate 4-glycanohydrolase, EC 3.2.1.35) was inactivated by butane-2,3-dione in either borate or Hepes buffer, pH 8.3. The presence of borate enhanced the inactivation process which followed pseudo-first-order kinetics with a calculated second-order rate constant of 13.54M-1 min-1. Using kinetic data it was estimated that the modification of 1 mol arginine per mol enzyme was sufficient for inactivation to occur, whereas amino acid analysis indicated that 4 mol arginine had been modified. The inactivation process was partially prevented by using either competitive inhibitors or substrates of the enzyme, thus indicating that the essential arginine residue is close to the active site of hyaluronidase. A full kinetic analysis of the enzyme with either hyaluronic acid or chondroitin 6-sulphate as substrate showed that the activity of hyaluronidase was uncompetitively activated by either protons or NaCl. The product obtained by reduction of the corboxyl groups of hyaluronic acid to the corresponding alcohol groups was a competitive inhibitor. The possibility that the microenvironment of hyaluronic acid was responsible for the observed kinetic effects of pH and ionic strength was dispelled. It is concluded that these data are compatible with a mechanism that involves anionic interaction between a carboxyl group on the substrate and an arginine residue on the enzyme.

Animals↗
PubMed1976

On the reaction kinetics in water of 1,3-propane sultone and 1,4-butane sultone: a comparison of reaction rates and mutagenic activities of some alkylating agents.

To determine correlations between the biological action pattern and chemical reactivity of alkylating agents, the rate constants for reactions of 1,3-propane sultone and 1,4-butane sultone with a series of nucleophiles at 37 degrees C have been determined. Previously published data on the mutagenicity of the two sultones and of some alkyl methanesulfonates and dialkyl sulfates towards Schizosaccharomyces pombe have been used in the evaluation of the dependence of mutagenic effectiveness on chemical reactivity. It is of interest to note that the mutagenic effectiveness of the two sultones, if expressed per alkylating event at a certain low nucleophilicity is the same as that of e.g. methyl methanesulfonate and ethyl methanesulfonate.

Alkanesulfonates↗
PubMed1990

Cytotoxicity, sister-chromatid exchanges and DNA single-strand breaks induced by 4-oxo-4-(3-pyridyl)butanal, a metabolite of a tobacco-specific N-nitrosamine.

The tobacco-specific N-nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), is metabolized by alpha-carbon hydroxylation to reactive diazohydroxides and aldehydes. The aim of this study was to determine the relative ability of one NNK-derived aldehyde, 4-oxo-4-(3-pyridyl)butanal, to induce cytotoxicity, sister-chromatid exchanges (SCEs) and DNA single-strand breaks (SSBs) in V79 cells. Our data demonstrate that this aldehyde is cytotoxic for V79 cells (IC50 = 0.4 mM) and induces SCEs at concentrations ranging from 0.01 to 0.5 mM. DNA SSBs were observed at concentrations ranging from 0.05 to 1 mM and were repaired within 8 h. When V79 cells were cultured with primary hepatocytes, there was a reduction in the frequency of SCEs induced by the aldehyde. This suggests that hepatocytes can partially deactivate the aldehyde. Our results suggest that this aldehyde is one of the reactive intermediates generated during NNK metabolism.

Animals↗
PubMed1995

The influence of the cysteine protease inhibitor L-trans-epoxysuccinyl-leucyl amido(4-guanidio)butane (E64) on photobiological effects of tetra(4-sulfonatophenyl)porphine.

Human cervix carcinoma cells of the line NHIK 3025 were exposed to light after 18 h incubation with tetra(4-sulfonatophenyl)porphine (TPPS4) in the absence or presence of the cysteine protease inhibitor L-trans-epoxysuccinyl-leucyl amido(4-guanidino)butane (E64) followed by 1 h in sensitizer-free medium. E64 changed the photochemical properties of TPPS4 in NHIK 3025 cells, i.e., TPPS4 fluorescence yield was enhanced 2.5-fold and photochemically induced lysosomal rupture and loss of cell bound TPPS4 were inhibited. Additionally, E64 slightly (10%) reduced the sensitivity of the NHIK 3025 cells to photoinactivation. This is not likely to be due to its inhibitory effect on protease activity, but correlates with its inhibition of lysosomal rupture. The present results indicate that the release of lysosomal cysteine proteases from the lysosomal compartments are of little or no importance in the photochemical inactivation of NHIK 3025 cells when TPPS4 is used as photosensitizer.

Carcinoma in Situ↗
PubMed2006

Evaluation of the eutomer of 4-{3-(4-chlorophenyl)-3-hydroxypyrrolidin-1-yl}-1-(4-fluorophenyl)butan-1-one, {(+)-SYA 09}, a pyrrolidine analog of haloperidol.

Enantiomeric separation of the racemic 4-{3-(4-chlorophenyl)-3-hydroxypyrrolidin-1-yl}-1-(4-fluorophenyl)butan-1-one, a pyrrolidine analog of haloperidol, {(+/-)-SYA 09}, and subsequent binding studies revealed that most of the binding affinity at dopamine and serotonin receptors resides in the (+)-isomer {(+)-SYA 09} or the eutomer. Further pharmacological evaluation of the eutomer revealed that it has a higher affinity for the dopamine D4 (DAD4) receptor subtype (Ki = 3.6 nM) than for the DAD2 subtype (Ki = 51.1 nM) with a ratio of 14.2 (D2Ki/D4Ki ratio = 14.2). In an animal model of antipsychotic efficacy, the (+)-SYA 09 was efficacious with an ED50 value of 1.6 mg/kg, i.p., and at twice this value, (+)-SYA 09 did not induce significant catalepsy in rats.

Animals↗
PubMed2006

Synthesis and antibacterial activities of new quinolone derivatives utilizing 1-azabicyclo[1.1.0]butane.

The ring-opening reactions of 1-azabicyclo[1.1.0]butane 3 with thiols 6a-f gave 3-sulfenylazetidine derivatives 7a-f in 50-92% yields. Treatment of 3 with aromatic amines 11a-e and dibenzylamine 11f in the presence of Mg(ClO(4))(2) afforded the corresponding 3-aminoazetidine derivatives 12a-f in 24-53% yields. These azetidine derivatives were introduced into the C7 position of a quinolone nucleus 8 to afford the corresponding fluoroquinolones 9a-f and 13a-f in 21-83% yields. Some of them exhibited superior antibacterial activity against quinolone-susceptible MRSA in comparison with clinically used fluoroquinolones, such as levofloxacin, ciprofloxacin, and gatifloxacin.

Anti-Bacterial Agents↗
PubMed2005

Interaction of gemini surfactants butane-1,4-diyl-bis(alkyldimethylammonium bromide) with DNA.

The size and structure of aggregates formed by interaction of DNA with homologous series of cationic gemini surfactants butane-1,4-diyl-bis(alkyldimethylammonium bromide) (CnGS, n=10-16 is the number of alkyl carbons) were investigated using UV-vis turbidity, dynamic light scattering and small-angle synchrotron X-ray (SAX) diffraction. The detailed analysis of turbidity in the range of lambda=450-600 nm indicates an anomaly in the growth of CnGS+DNA aggregates with increasing concentration of CnGS, possibly involving changes of structure and size of aggregates. Using dynamic light scattering, changes of the effective diameter of CnGS+DNA (n=12 and 16) aggregates formed in the CnGS concentration range 0.002-0.140 mmol/l were observed. SAX diffractograms show the presence of long-range organization of CnGS+DNA (n=12, 13, 14 and 16) aggregates due to DNA interaction with CnGS above the critical micellar concentration. The CnGS+DNA (n=12, 13 and 14) aggregates at 25 degrees C are packed in a lattice of two-dimensional hexagonal symmetry. With increasing C14GS:DNA molar ratio the changes of the lattice parameter in the range of 4.80-5.27 nm are observed at 25 degrees C. The aggregates undergo structural changes induced by temperature in the range 60-95 degrees C, which are accompanied by changes of the diffraction patterns, namely in the region of reciprocal spacing s=0.15-0.30 nm(-1).

Butylamines↗
PubMed2005

Preparation of USY zeolite VOx supported catalysts from V(AcAc)3 and NH4VO3. Catalytic properties for the dehydrogenation of n-butane in oxygen-free atmosphere.

The preparation of different samples of vanadia supported on ultrastable zeolite (VO(x)/USY) is discussed. The samples were prepared in order to obtain highly dispersed V-species, avoiding the formation of crystalline vanadia and the destruction of the zeolite framework. Two methods were employed for preparing VO(x)/USY samples: an organic route using V(AcAc)3 and an inorganic route using NH4VO3. The characterization of the samples was performed with XRD, TPR, NH3-TPD, and N2 isotherms. From these results it is concluded that when VO(x) is supported on the surface of USY from acidic aqueous solution of ammonium metavanadate, the destruction of the zeolite framework is accomplished. For higher pH values in the impregnating solution, undesired V2O5 is formed on the USY surface. On the other hand, VO(x)/USY prepared from the organic precursor shows no destruction of the USY structure. In addition, highly dispersed VO(x) are formed, though for relatively high V loadings (6%) an obstruction of the zeolite windows takes place. The samples are tested as catalysts for gas phase dehydrogenation of n-butane to olefins. The catalysts prepared from NH4VO3 are almost inactive for the reaction. On the other hand, both samples prepared from V(AcAc)3 present initial conversion levels in the 8-12% range. However, the selectivity depends on the V loading, the catalysts with 6% loading being the most selective (75%). The catalytic patterns of the samples (activity and selectivity) are in agreement with the physicochemical features of the VO(x)/USY surface.

Journal Article↗
PubMed1997

Interaction of the DNA topoisomerase II catalytic inhibitor meso-2,3-bis(3,5-dioxopiperazine-1-yl)butane (ICRF-193), a bisdioxopiperazine derivative, with the conserved region(s) of eukaryotic but not prokaryotic enzyme.

ICRF-193 [meso-2,3-bis(3,5-dioxopiperazine-1-yl)butane], a bisdioxopiperazine compound, has been shown to be a catalytic inhibitor of DNA topoisomerase II by stabilizing the enzyme in the form of a closed "protein clamp," an intermediate form in the catalytic cycle (Roca et al., Proc Natl Acad Sci USA 91: 1781-1785, 1994). In view of its usefulness as a probe in the functional analysis of the enzyme, we tried further to define the domain(s) of the enzyme interacting with the drug by examining its inhibitory activity on type II topoisomerases from various species of eukaryotes and prokaryotes. ICRF-193 inhibited the enzyme from yeast, fly, frog, plant, and mammals at IC50 values in the range of 1-13 microM. Experiments using fission yeast truncated mutant type II enzyme lacking both amino-terminal 74 amino acids and carboxy-terminal 265 amino acids revealed that ICRF-193 interacts with the 125 kDa "core" polypeptide of the enzyme. In contrast, prokaryotic type II enzymes, Escherichia coli DNA gyrase, topo IV, and phage T4 topo, were not affected by the drug. From these results, the domain(s) common to eukaryotic but not to prokaryotic type II enzymes interacting with ICRF-193 was speculated.

Amino Acid Sequence↗
PubMed1998

Synthesis of alpha,alpha-, alpha,Beta-, and Beta,Beta-(dimaltoside)s of ethane-1,2-diol, propane-1,3-diol, and butane-1,4-diol: a proposal for an initial adhesion mode.

Nine dimaltoside derivatives of ethane-1,2-diol, propane-1,3-diol, and butane-1,4-diol having the alpha,alpha, alpha,beta, and beta,beta anomeric configurations at the linkage sites have been synthesized. Suitably protected maltosyl halides or a 1-(phenylthio) derivative were condensed with the foregoing diols and the resulting monomaltosyl derivatives were further condensed with the maltosyl donors to give, after deprotection, the title compounds. Their structures were fully characterized by NMR spectroscopy. Interactions between the three alpha,alpha-(dimaltoside)s and cinnamyl alcohol are briefly discussed.

Carbohydrate Conformation↗
PubMed2000

4-Dialkylamino-1-(5-substituted or unsubstituted 1-phenyl-1H-pyrazol-4-yl)butan-1-ols: synthesis and evaluation of analgesic, anti-inflammatory and platelet anti-aggregating activities.

A number of 4-dialkylamino-1-(5-substituted or unsubstituted 1-phenyl-1H-pyrazol-4-yl)butan-1-ols 2a-n were synthesized and tested in vivo for anti-inflammatory and analgesic activities and in vitro for platelet anti-aggregating activity. Dimethylaminoderivatives 2b, e, g showed good analgesic activity; almost all of them had strong platelet anti-aggregating properties at a final concentration of 1 x 10(-3) M; pyrazoles 2c, d, f-h showed weak anti-inflammatory activity.

Analgesics↗
PubMed2002

Spectrophotometric determination of copper in pharmaceutical and biological samples with 3-[2-[2-(2-hydroxyimino-1-methyl-propylideneamino)-(ethylamino]-ethyl-imino]-butan-2-one oxime).

3-[2-[2-(2-hydroxyimino-1-methyl-propylideneamino)-ethylamino]-ethyl-imino]-butan-2-one oxime, (H(2)mdo) reacts with copper(II) to form a highly stable 1:1 complex in alkaline medium at room temperature. The complex gives a maximum absorption at 570 nm with a molar absorptivity coefficient of 0.16 x 10(4) l mol(-1) cm(-1). A spectrophotometric method using this ligand was developed and optimized in terms of pH, stability of the complex, amount of reagent required, sensitivity, linearity and tolerance limits of various foreign ions. The linear range for copper determination is 0.2-225 mg l(-1). The method is sensitive, accurate and tolerant to many foreign substances, and, all the reagents used are stable under the conditions. Moreover, the method is easy to perform for the determination of copper in pharmaceutical and biological samples.

Copper↗
PubMed2001

Antagonists of the human CCR5 receptor as anti-HIV-1 agents. part 1: discovery and initial structure-activity relationships for 1 -amino-2-phenyl-4-(piperidin-1-yl)butanes.

Screening of the Merck sample collection for compounds with CCR5 receptor binding afforded (2S)-2-(3,4-dichlorophenyl)-1-[N-(methyl)-N-(phenylsulfonyl)amino]-4-[spiro(2,3-dihydrobenzthiophene-3,4'-piperidin-1'-yl)]butane S-oxide (4) as a potent lead structure having an IC50 binding affinity of 35 nM. Herein, we describe the discovery of this lead structure and our initial structure activity relationship studies directed toward the requirement for and optimization of the 1-amino fragment.

Animals↗
PubMed2002

Controlling the framework formation of silver(I) coordination polymers with 1,4-bis(phenylthio)butane by varying the solvents, metal-to-ligand ratio, and counteranions.

The reactions of 1,4-bis(phenylthio)butane (L) with Ag(I) salts in varied conditions (varying the solvents, metal-to-ligand ratios, and counteranions) lead to the formation of four new two-dimensional (2D) coordination polymers with different network structures: [Ag(2)L(3)(ClO(4))(2)](infinity) 1, [Ag(2)L(3)(ClO(4))(2) x CH(3)OH](infinity) 2, [[AgL(2)](ClO(4))](infinity) 3, and [AgLNO(3)](infinity) 4. All the structures were established by single-crystal X-ray diffraction analysis. Crystal data for 1: triclinic, P-1, a = 11.0253(9) A, b = 11.3455(9) A, c = 11.5231(9) A, alpha = 93.931(2) degrees, beta = 92.689(2) degrees, gamma = 112.9810(10) degrees, Z = 2. 2: triclinic, P-1, a = 11.9147(13) A, b = 16.1534(17) A, c = 16.2259(17) A, alpha = 74.977(2) degrees, beta = 69.030(2) degrees, gamma = 69.986(2) degrees, Z = 2. 3: triclinic, P-1, a = 12.1617(9) A, b = 12.5054(10) A, c = 13.1547(10) A, alpha = 64.3370(10) degrees, beta =85.938 (2) degrees, gamma = 69.3010(10) degrees, Z = 2. 4: monoclinic, P2(1)/c, a = 5.4032(17) A, b = 16.974(6) A, c = 19.489(6) A, beta = 94.234(6) degrees, Z = 4. In all four complexes, each Ag(I) center has a tetracoordination geometry, and the 2D networks consist of fused large macrometallacyclic ring systems. The "hexagonal" 42-membered rings, Ag(6)L(6), observed in 1 and 2 are nearly identical, which could be considered as unique examples of self-sustaining noninterpenetrated frameworks formed with flexible ligands. The repeating rectangular 28-membered macrometallacycle, Ag(4)L(4), is the basis for the network of 3, in which the perchlorate anions occupy the voids to prevent the ring from collapsing. In 4, columns of the fused rectangular 22-membered rings, Ag(4)L(2)(NO(3))(2), are cross-linked through the L ligands to form a unique 2D network consisting of two types of 22-membered repeating units.

Journal Article↗
PubMed2004

Structure and physical properties of [micro-tris(1,4-bis(tetrazol-1-yl)butane-N4,N4')iron(II)] bis(hexafluorophosphate), a new Fe(II) spin-crossover compound with a three-dimensional threefold interlocked crystal lattice.

[micro-Tris(1,4-bis(tetrazol-1-yl)butane-N4,N4')iron(II)] bis(hexafluorophosphate), [Fe(btzb)(3)](PF(6))(2), crystallizes in a three-dimensional 3-fold interlocked structure featuring a sharp two-step spin-crossover behavior. The spin conversion takes place between 164 and 182 K showing a discontinuity at about T(1/2) = 174 K and a hysteresis of about 4 K between T(1/2) and the low-spin state. The spin transition has been independently followed by magnetic susceptibility measurements, (57)Fe-Mössbauer spectroscopy, and variable temperature far and midrange FTIR spectroscopy. The title compound crystallizes in the trigonal space group P3 (No. 147) with a unit cell content of one formula unit plus a small amount of disordered solvent. The lattice parameters were determined by X-ray diffraction at several temperatures between 100 and 300 K. Complete crystal structures were resolved for 9 of these temperatures between 100 (only low spin, LS) and 300 K (only high spin, HS), Z = 1 [Fe(btzb)(3)](PF(6))(2): 300 K (HS), a = 11.258(6) A, c = 8.948(6) A, V = 982.2(10) A(3); 100 K (LS), a = 10.989(3) A, c = 8.702(2) A, V = 910.1(4) A(3). The molecular structure consists of octahedral coordinated iron(II) centers bridged by six N4,N4' coordinating bis(tetrazole) ligands to form three 3-dimensional networks. Each of these three networks is symmetry related and interpenetrates each other within a unit cell to form the interlocked structure. The Fe-N bond lengths change between 1.993(1) A at 100 K in the LS state and 2.193(2) A at 300 K in the HS state. The nearest Fe separation is along the c-axis and identical with the lattice parameter c.

Journal Article↗