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At least 73 records · Page 4Linked to original sources
PubMed1988

Inhibition of cathepsin B by peptidyl aldehydes and ketones: slow-binding behavior of a trifluoromethyl ketone.

Inhibition of the cysteine proteinase cathepsin B by a series of N-benzyloxycarbonyl-L-phenylalanyl-L-alanine ketones and the analogous aldehyde has been investigated. Surprisingly, whereas the aldehyde was found to be almost as potent a competitive reversible inhibitor as the natural peptidyl aldehyde, leupeptin, the corresponding trifluoromethyl ketone showed comparatively weak (and slow-binding) reversible inhibition. Evaluation of competitive hydration and hemithioketal formation in a model system led to a structure-activity correlation spanning several orders of magnitude in both cathepsin B inhibition constants (Ki) and model system equilibrium data (KRSH,apparent).

Aldehydes↗
PubMed2005

Sc(OTf)3-catalyzed indolylation of 1,2-allenic ketones: controlled highly selective synthesis of beta-indolyl-alpha,beta-unsaturetated (E)-enones and beta,beta-bisindolyl ketones.

[reaction: see text] A novel highly stereoselctive synthesis of beta-indolyl-alpha,beta-unsaturated (E)-enones by the hydroindolylation of the beta,gamma-C=C bond of 1,2-allenic ketones in the presence of 5 mol % Sc(OTf)(3) was developed. beta,beta-Bisindolyl ketones were prepared by using 2.5 equiv of indoles. A stepwise protocol for introducing different indoles was also established.

Catalysis↗
PubMed1976

Peripheral nerve changes induced by methyl n-butyl ketone and potentiation by methyl ethyl ketone.

A study of the sequential morphological changes in the peripheral nerve induced by experimental inhalation exposure of methyl n-butyl ketone (MBK) revealed that the earliest change was an increase in the number of neurofilaments in the large myelinated nerve fibers. This change occurred prior to axonal swelling or myelin thinning. As the duration of exposure lengthened the number of neurofilaments gradually increased and ultimately produced axonal swelling with secondary thinning of the myelin sheath. This appears to be the pathogenesis of the "giant axonal" neuropathy. Another change observed early in this neuropathy was the presence of inpouchings of the myelin sheath, which also increased in number in parallel to the duration of exposure. A careful study of the sequential changes in the entire motor unit did not show a predilection for early morphological changes at the axon terminal. Abnormalities at the neuromuscular junction occurred only after a full spectrum of changes were seen in the main nerve trunk, nerve roots and intramuscular nerves. An important observation was the marked potentiation of peripheral neurotoxicity observed when animals were exposed to MBK in combination with methyl ethyl ketone (MEK) at a ratio of 1:5, MBK:MEK. The latter solvent showed no neurotoxic effect alone. This might help explain a recent outbreak of a polyneuropathy affecting many workers. One further observation was that the sural nerve of a patient with prolonged exposure to MBK showed changes similar to those induced experimentally.

Adult↗
PubMed1993

Arterial ketone body ratio and glucose administration as an energy substrate in relation to changes in ketone body concentration after living-related liver transplantation in children.

Changes in the arterial ketone body ratio (AKBR [acetoacetate/3-hydroxybutyrate]), which reflect the redox state of the liver mitochondria (NAD+/NADH), as well as those in total ketone body concentration (TKB) and blood glucose level were studied in 30 living-related liver transplantations (LRLT) performed in pediatric patients at Kyoto University Hospital from June 1990 to January 1992. AKBR increased to over 1.0 within 6 hr after reperfusion of the graft in 11 cases (37%), within 12 hr in 7 (23%), on POD 1 in 8 (27%), and on POD 2 in the remaining 4 cases (13%). TKB significantly increased while AKBR remained below 0.7 (266 +/- 40 mumol/L), but it significantly decreased in accordance with the recovery of AKBR above 1.0 (61 +/- 6 mumol/L). This indicates the change in the predominant energy substrate for hepatic mitochondria from fatty acid to glucose during the AKBR recovery process. In 6 cases, the AKBR transiently decreased to below 1.0 after initial recovery concomitant with the fall in blood glucose level and the increase in TKB. However, the AKBR was rapidly restored to over 1.0 again immediately after the glucose administration was increased. This suggests that glucose administration to maintain blood glucose level between 150 and 250 mg/dl is essential for the AKBR recovery above 1.0 that accompanies the normalization of graft metabolic functions, and that, along with the postoperative minimal increase in serum enzymes and favorable outcome of the transplant with no incidence of a primary nonfunctioning graft, the prompt and successful recovery of AKBR reflects the expected high viability of the graft in our LRLT cases.

Adolescent↗
PubMed1989

The hydrogenation of alpha-hydroxymethylene-ketone derivatives to alpha-hydroxymethyl-ketone derivatives with a cell-free system of Streptomyces cinereocrocatus.

2',3'-Dihydro-5'-formylgriseofulvin (3), oxymetholone (5), and 3 beta-acetoxy-16-acetoxymethylene-5-androsten-17-one (9) were used as the substrates of a cell-free system from Streptomyces cinereocrocatus NRRL 3443. The results indicated that S. cinereocrocatus contains enzymatic activities which reduce the above three alpha-hydroxymethylene-ketones to the corresponding alpha-hydroxymethyl-ketones.

Hydrogenation↗
PubMed1983

A comparison of the mutagenicity and macromolecular binding of the carcinogens Michler's ketone and reduced Michler's ketone.

The mutagenicity of 4,4'-bis(dimethylamino)benzophenone (Michler's ketone, MK, CAS No. 90-94-8) and 4,4'-methylenebis(N,N-dimethyl)benzamine (reduced Michler's ketone, RMK, CAS No. 101-61-1) for Salmonella typhimurium strain TA100 was compared using activated 9000 X g (S9) liver supernatants from 2 animal species. RMK, but not MK, was mutagenic when incubated with phenobarbital-induced B6D2F1 mouse or Osborne-Mendel rat-liver S9. The mutagenic response for RMK was linear at doses from 1 to 33 micrograms/plate. A higher percentage of RMK and MK became irreversibly bound to mouse-liver macromolecules than to rat-liver macromolecules when incubated at 37 degrees C in the presence of reduced nicotinamide adenine dinucleotide phosphate.

Aniline Compounds↗
PubMed2003

Intramolecular Pd-mediated processes of amino-tethered aryl halides and ketones: insight into the ketone alpha-arylation and carbonyl-addition dichotomy. A new class of four-membered azapalladacycles.

An exploration of the scope and limitations of Pd(0)-catalyzed intramolecular coupling reactions of amino-tethered aryl halides and ketones has been conducted. Two different and competitive reaction pathways starting from omega-(2-haloanilino) alkanones, enolate arylation and addition to the carbonyl group, have been observed, while omega-(2-halobenzylamino) alkanones exclusively underwent the enolate arylation process. The dichotomy between ketone alpha-arylation and carbonyl-addition in the reactions of omega-(2-haloanilino) alkanones has been rationalized by the intermediacy of unprecedented four-membered azapalladacycles, from which X-ray data and chemical behavior are reported.

Journal Article↗
PubMed2003

A novel approach of cycloaddition of difluorocarbene to alpha,beta-unsaturated aldehydes and ketones: synthesis of gem-difluorocyclopropyl ketones and 2-fluorofurans.

A series of gem-difluorocyclopropyl acetals and ketals are easily obtained in moderate yields from the [1 + 2] cycloaddition of difluorocarbene to 1,3-dioxolanes of alpha,beta-unsaturated aromatic aldehydes and ketones. Hydrolysis of these fluorinated compounds under acidic conditions either gives the corresponding gem-difluorocyclopropyl ketones or 1-aryl-2-fluorofuran derivatives through intramolecular carbonium rearrangement with simultaneous ring cleavage.

Journal Article↗
PubMed2005

Di-2-pyridyl ketone oxime [(py)2CNOH] in manganese carboxylate chemistry: mononuclear, dinuclear and tetranuclear complexes, and partial transformation of (py)2CNOH to the gem-diolate(2-) derivative of di-2-pyridyl ketone leading to the formation of NO3-.

The use of di-2-pyridyl ketone oxime, (py)2CNOH, in manganese carboxylate chemistry has been investigated. Using a variety of synthetic routes complexes [Mn(O2CPh)2{(py)2CNOH}2].0.25H2O (1.0.25H2O), Mn4(O2CPh)2{(py)2CO2}2{(py)2CNO}2Br2].MeCN (2.MeCN), [Mn4(O2CPh)2{(py)2CO2}2{(py)2CNO}2Cl(2)].2MeCN (3.2MeCN), [Mn4(O2CMe)2{(py)2CO2}2{(py)2CNO}2Br2].2MeCN (4.2MeCN), [Mn4(O2CMe)2{(py)2CO2}2{(py)2CNO}2(NO3)2].MeCN.H2O (5.MeCN.H2O) and [Mn2(O2CCF3)2(hfac)2{(py)2CNOH}2] (6) have been isolated in good yields. Remarkable features of the reactions are the in situ transformation of an amount of (py)2CNOH to yield the coordination dianion, (py)2CO2(2-), of the gem-diol derivative of di-2-pyridyl ketone in 2-5, the coordination of nitrate ligands in 5 although the starting materials are nitrate-free and the incorporation of CF3CO2- ligands 6 in which was prepared from Mn(hfac)(2).3H2O (hfac(-)= hexafluoroacetylacetonate). Complexes 2-4 have completely analogous molecular structures. The centrosymmetric tetranuclear molecule contains two MnII and two MnIII six-coordinate ions held together by four mu-oxygen atoms from the two 3.2211 (py)2CO2(2-) ligands to give the unprecedented [MnII(mu-OR)MnIII(mu-OR)2MnIII(mu-OR)MnII]6+ core consisting of a planar zig-zag array of the four metal ions. Peripheral ligation is provided by two 2.111 (py)2CNO-, two 2.11 PhCO2- and two terminal Br- ligands. The overall molecular structure 5 of is very similar to that of 2-4 except for the X- being chelating NO3-. A tentative reaction scheme was proposed that explains the observed oxime transformation and nitrate generation. The CF3CO2- ligand is one of the decomposition products of the hfac- ligand. The two Mn(II) ions are bridged by two neutral (py)2CNOH ligands which adopt the 2.0111 coordination mode. A chelating hfac- ligand and a terminal CF3CO2- ion complete a distorted octahedral geometry at each metal ion. The CV of complex reveals irreversible reduction and oxidation processes. Variable-temperature magnetic susceptibility studies in the 2-300 K range for the representative tetranuclear clusters 2 and 4 reveal weak antiferromagnetic exchange interactions, leading to non-magnetic ST = 0 ground states. Best-fit parameters obtained by means of the program CLUMAG and applying the appropriate Hamiltonian are J(Mn(II)Mn((III))=-1.7 (2), -1.5 (4) cm(-1) and J(Mn(III)Mn(III))=-3.0 (2, 4) cm(-1).

2,2'-Dipyridyl↗
PubMed2001

The first pyridyl N,N'-coordinated di-2-pyridyl ketone oxime, fac-tricarbonylchloro(di-2-pyridyl ketone oxime)rhenium(I) dimethyl sulfoxide solvate.

The structure of the first metal compound of pyridyl N,N'-coordinated di-2-pyridyl ketone oxime (dpk-o), fac-tricarbonylchloro(di-2-pyridyl-kappaN ketone oxime)rhenium(I) dimethyl sulfoxide solvate, [ReCl(C(11)H(9)N(2)O)(CO)(3)].C(2)H(6)OS, (I), is reported. The coordinated atoms (two N atoms from the pyridyl rings, three C atoms from the carbonyl groups and one Cl atom) are in a distorted octahedral arrangement, with the major distortion being due to the constraints associated with the binding of dpk-o. The packing of the molecules shows antiparallel tapes of (I), with a network of classical (O...H-O) and non-classical (O...H-C) hydrogen bonds between the dimethyl sulfoxide solvate molecule and the complexed metal moiety.

Journal Article↗
PubMed2002

[Development of gas chromatographic method for chiral analysis of acrylic ketone alcohol and acrylic ketone acetate].

A gas chromatographic method was developed to directly determine the enantiomers of acrylic ketone alcohol and acrylic ketone acetate. Two pairs of enantiomers were nearly baseline-separated by using Model HP-5890 Gas Chromatograph with flame ionization detector and WCOT CD-Chiral-DEX CB (30 m x 0.25 mm i.d.) column. The optimum conditions were the split ratio of 30:1 for the sample injected, the flow rates of 3.7 mL/min for the carrier gas (nitrogen), 60 mL/min for the hydrogen, and 250 mL/min for the oxygen, and temperatures of 148 degrees C for the column, 230 degrees C for the injector, and 230 degrees C for the detector. The linearity and reproducibility were satisfactory. The regression coefficients were over 0.9965. The RSDs obtained were less than 1.25%. The method was further used to trace the reactants and products, and to evaluate the enzyme catalyst activity and selectivity under different conditions. The results show that the method developed is very successful.

Acrylates↗
PubMed1991

Opioid receptor labeling with the chloromethyl ketone derivative of [3H]Tyr-D-Ala-Gly-(Me)Phe-Gly-ol (DAMGO) II: Covalent labeling of mu opioid binding site by 3H-Tyr-D-Ala-Gly-(Me)Phe chloromethyl ketone.

Opioid receptors of rat brain membranes were prelabeled with 3H-Tyr-D-Ala2-(Phe4)-Gly-CH2Cl, a chloromethyl ketone derivative of enkephalin, and solubilized in 1% digitonin. Hydrodynamic parameters of the receptor detergent complex derived from gel filtration and sucrose density gradient ultracentrifugation were found to be 51 A and 8.7 S, respectively, and the size was estimated to be about 200 kDa. Sodium dodecyl sulfate gel electrophoresis followed by fluorography revealed specific alkylation of a major protein at 58 kDa.

Amino Acid Chloromethyl Ketones↗
PubMed1994

Inhibition of human neutrophil elastase with peptidyl electrophilic ketones. 2. Orally active PG-Val-Pro-Val pentafluoroethyl ketones.

Valylprolyvalyl pentafluoroethyl ketones with different N-protecting groups were evaluated in vitro and in vivo as inhibitors of human neutrophil elastase (HNE). Several of these compounds were found to be orally active in HNE-induced rat and hamster lung hemorrhage models. The compound with 4-(4-morpholinylcarbonyl)benzoyl as the protecting group, 71 (MDL 101,146), was studied in greater detail. Hydration and epimerization studies were performed on 71 and related compounds in various media, including human blood serum. High-performance liquid chromatography studies on a reversed-phase system as a measure of the lipophilicity of 71 and related compounds revealed a small range of relative retention times wherein the orally active compounds fell. The Ki value determined for 71 vs HNE was 25 nM.

Administration, Oral↗
PubMed2004

Base-promoted reactions of bridged ketones and 1,3- and 1,4-haloalkyl azides: competitive alkylation vs azidation reactions of ketone enolates.

The reactions of 1,3- and 1,4-haloalkyl azides with enolates of 2-norbornanone (and a ring-expanded analog) afford polycyclic 1,2,3-triazolines in good yields. The reaction occurs by the initial azidation of the ketone enolate, followed in order by triazoline formation and O-alkylation. An interesting element of this process is the preferential reaction of the alkyl azide with an enolate anion as opposed to the more familiar reaction of the alkyl halide (including Cl and I derivatives). Reactions of acyclic or monocyclic enolates generally lead to 1,2,3-triazoles but none of the alternative C-alkylation product.

Alkylation↗
PubMed1982

Biological monitoring of occupational exposure to methyl ethyl ketone by means of urinalysis for methyl ethyl ketone itself.

Head space gas chromatography (GC) was applied to measure methyl ethyl ketone (MEK) in urine from 62 MEK-exposed male workers, whose individual intensity of exposure to MEK was monitored utilizing the carbon felt dosimeter. The urinary MEK level increased rapidly to reach a plateau in the first quarter of the daily 8-h work, while very little MEK was detected in the preshift urine. When the MEK levels in the urine at the end of the shift were compared with the afternoon MEK-TWA values, the uncorrected MEK in urine correlated best with MEK in air (r = 0.774, n = 62), while correction for creatinine gave a comparable result and the correlation was poorer when corrected for a specific gravity of urine or for the lapse of time after preceding passage of urine. Balance of MEK absorption via inhalation and MEK excretion into urine revealed that only 0.1% of MEK absorbed will be excreted unchanged into urine. Wider application of head space GC is discussed for the analysis of unmetabolized solvents in urine.

Air Pollutants↗