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The microbial metabolism of acetophenone. Metabolism of acetophenone and some chloroacetophenones by an Arthrobacter species.

1. An organism that utilizes acetophenone as sole source of carbon and energy was isolated in pure culture and tentatively identified as an Arthrobacter sp. 2. Cell-free extracts of the acetophenone-grown organism contained an enzyme, acetophenone oxygenase, that catalysed an NADPH-dependent consumption of O(2) in the presence of the growth substrate; approx. 1mol of O(2) and 1mol of NADPH were consumed per mol of acetophenone oxidized. 3. Cell-free extracts also contained an enzyme capable of the hydrolysis of phenyl acetate to phenol and acetate. The amount of this esterase was increased markedly by growth on acetophenone. 4. The observed products of the acetophenone oxygenase reaction by crude cell-free extracts were phenol and acetate. However, inhibition of the phenyl acetate esterase by paraoxon resulted in the formation of phenyl acetate from acetophenone. 5. A degradative sequence is proposed in which acetophenone is metabolized by an oxygen-insertion reaction to form phenyl acetate. Further metabolism occurs by hydrolysis of this ester. 6. The organism and extracts were shown to metabolize chlorinated acetophenones. The environmental implications of this observation are discussed.

Acetophenones

Microbial conversion of ethylbenzene to 1-phenethanol and acetophenone by Nocardia tartaricans ATCC 31190.

A culture of Nocardia tartaricans ATCC 31190 was capable of catalyzing the conversion of ethylbenzene to 1-phenethanol and acetophenone while growing in a shake flask culture with hexadecane as the source of carbon and energy. This subterminal oxidative reaction with ethylbenzene appears not to have been previously reported for Nocardia species. When N. tartaricans was grown on glucose as its source of carbon and energy and ethylbenzene was added, no subsequent production of 1-phenethanol or acetophenone was observed. The mechanisms of 1-phenethanol and acetophenone production from ethylbenzene are thought to involve a subterminal oxidation of the alpha-carbon of the alkyl group to 1-phenethanol followed by biological oxidation of the latter to acetophenone.

Acetophenones

[Synthesis of 5-azido-3-nitro-omega-bromo-acetophenone- a photochemically active bifunctional reagent for the cross-linking of biopolymers].

The photochemically activatable heterobifunctional reagent 5-azido-3-nitro-omega-bromo-acetophenone (3) was synthesized by condensation of 3,5-dinitrobenzoyl chloride with diethyl malonate, acid-catalyzed decarboxylation of the formed malonester derivative 1 to 3,5-dinitro-acetophenone (2a), selective reduction of one nitro group in 2a to 5-amino-3-nitro-acetophenone (2b) and diazotization to 2c. Nucleophilic displacement of the diazonium group in 2c by sodium azide forms 5-azido-3-nitro-acetophenone (2d) which gives 3 after bromination. Compound 3 is photochemically labile and forms an highly reactive nitrene during ultraviolet irradiation. Since compound 3 is able to alkylate amino- or mercapto-groups of amino acids or nucleosides via its bromoacetyl residue, the bifunctional reagent 3 should cross link proteins or nucleic acids after nitrene generation.

Acetophenones

Mutagenicity of flavones, chromones and acetophenones in Salmonella typhimurium. New structure-activity relationships.

28 flavones and 11 structurally-related flavonoids, chromones, and acetophenones, were tested for mutagenicity in the Salmonella typhimurium his reversion assay. 7 flavones, all of which were hydroxy- or methoxy-substituted at position 8, were moderate to strong mutagens in strain TA100 in the presence of rat liver S9 mix. In each case, the response of strain TA98 was either not significant or was very much weaker than that observed in strain TA100. The activation by S9 is not mediated by the microsomal cytochrome P450 system, since activation was not diminished when microsomes were removed by centrifugation at 100 000 X g. The observed strain specificity and structural requirements for activity indicate a mutagenic mechanism different from that associated with previously reported mutagenic flavonols (3-hydroxy-flavones) which are most active in strain TA98. The most mutagenic flavone investigated, 5,7,8-trihydroxy-flavone (norwogonin), had a potency of 17 revertants/nmole. Simplification of the chemical structures to hydroxy-substituted chromone and acetophenone systems revealed similar strain specificity, hydroxylation requirements, and S9 dependence within these structural classes, suggesting a similar activation pathway and mutagenic mechanism. The greatest mutagenic potency was observed within the flavone series, but significant potency was retained by similarly hydroxylated chromones and acetophenones. No mutagenic activity was observed in the absence of the aryl ketone moiety.

Acetophenones

Gas chromatographic analysis of acetophenone oxime and its metabolites.

A gas-liquid chromatographic (GLC) method has been developed for monitoring the metabolic reduction of acetophenone oxime or oxidative metabolism of the corresponding amine, alpha-methylbenzylamine in liver homogenates. The oxime, amine, n-hydroxy-alpha-methylbenzylamine and acetophenone are quantitatively determined after GLC separation of components with temperature programming on an SP-2401-DB-coated column. The first three compounds were silylated with N,O-bis(trimethylsilyl)-acetamide prior to chromatographic analysis to enhance the stability and improve the chromatographic properties of these components. The effluent gas was monitored with flame ionization detection, and permitted quantitation of components at sub-microgram/ml levels with reproducibility between injections of +/-2%. The optimal composition of enantiomeric mixtures of (R,S)-alpha-methylbenzylamines formed during metabolic reduction of acetophenone oximes were determined by conversion to diastereomeric amides and subsequent GLC analysis.

Acetophenones

Leukotriene receptor antagonists. 2. The [[(tetrazol-5-ylaryl)oxy]methyl]acetophenone derivatives.

A series of [[(tetrazol-5-ylaryl)oxy]methyl]acetophenones was synthesized and evaluated as antagonists of leukotriene D4 induced contractions of guinea pig ileum. Substitutions at the 3-position of the acetophenone with ethyl (66), propyl (68), butyl (83), and isobutyl (84) gave -log IC50 values of 7.9, 8.0, 7.8, and 7.7, respectively. Equally potent compounds were obtained when the tetrazol-5-yl group was connected to the second benzene ring in the para position with a chemical bond (67), methylene (68), or ethylene (71). For retention of high antagonist activity, the acetophenone should be substituted in the 2-position by a hydroxyl group and the tetrazole ring should have an acidic hydrogen atom. 1-[2-Hydroxy-3-propyl-4-[[4-(1H-tetrazol-5-ylmethy) phenoxy]methyl]phenyl]ethanone (68, LY1632443) has undergone extensive pharmacologic evaluation for its potential as an antiasthma agent.

Acetophenones

Hypolipidemic activity of o-(N-phthalimido)acetophenone in Sprague Dawley rats.

o-(N-Phthalimido)acetophenone has proven to be an effective hypolipidemic agent in rats at 20 mg/kg/day orally. The agent suppressed the activity of the rate-limiting enzyme of the liver involved in de novo synthesis of triglycerides. The synthetic rate-limiting enzyme for cholesterol esters was also inhibited by the drug in vivo. o-(N-Phthalimido)acetophenone lowered cholesterol in the liver and the aorta wall and generally caused an increase in phospholipids in body tissues. Serum lipoproteins were modulated by the drug with a decrease in cholesterol and triglycerides in the chylomicron, very low-density lipoproteins (VLDL), and low-density lipoproteins (LDL) and an increase in high-density lipoprotein (HDL) cholesterol. The phospholipid content was increased in the chylomicron, VLDL, and LDL fractions. In hyperlipidemic rats, o-(N-phthalimido)acetophenone lowered elevated blood lipid levels at 20 mg/kg/day orally after 3 weeks of administration. The hypolipidemic rat after drug treatment had a lower LDL cholesterol and a higher HDL cholesterol content, which is therapeutically desirable to protect against cardiovascular disease.

Acetophenones

The disposition of the hypolipidemic agent, o-(N-phthalimido)acetophenone, in Sprague-Dawley rats.

Disposition studies of the potent experimental hypolipidemic agent, o-(N-phthalimido)acetophenone, were conducted in the laboratory rat. Intravenous administration of the drug demonstrated a declining biphasic plasma concentration-time curve suggesting a rapid distribution into tissues. Less than 5% of the intravenous dose was recovered in urine and feces after 5 days. Oral administration of the drug showed that the maximum blood levels were attained within 15 min. After 48 hr, 92% of the orally administered 14C dose was eliminated either via urine (60%) or feces (40%). 14C in a 0-24-hr urine collection after oral administration showed that urinary radioactivity was composed of 22% of the parent compound o-(N-phthalimido) acetophenone, a benzoic acid metabolite (22%) o-(N-phthalimido)benzoic acid, and an amic acid metabolite (56%) N-(o-acetophenone)phthalamic acid. The two metabolites were unconjugated and possessed less hypolipidemic activity than the parent drug.

Acetophenones

Attenuation of the development of hypertension in spontaneously hypertensive rats by the thromboxane synthetase inhibitor, 4'-(imidazol-1-yl) acetophenone.

The compound 4'-(imidazol-1-yl) acetophenone was demonstrated to be a selective thromboxane (Tx) synthetase inhibitor in spontaneously hypertensive rats (SHR). Serum TxB2 concentrations (from clotted blood) were suppressed by 89.1% (p less than 0.001) and 41.2% (p less than 0.01) at 3 and 24 hours, respectively, following a single subcutaneous injection of 100 mg/kg of 4'-(Imidazol-1-yl) acetophenone suspended in olive oil. In contrast, plasma 6-keto-PGF1 alpha levels were not significantly altered at 3 hours following injection - a time when suppression of TXB2 was maximal. From 4 to 10 weeks of age, SHR were treated with daily injections of either 4'-(Imidazol-1-yl) acetophenone (100 mg/kg) in olive oil or olive oil alone. By 8 weeks of age systolic blood pressures in the treated group were 140.6 +/- 3.2 vs 156.6 +/- 4.5 mmHg in the control group (p less than 0.01). At ten weeks of age the separation was even more pronounced: 155.3 +/- 3.7 vs. 184.8 +/- 4.6 mmHg for treated vs. control animals (p less than 0.001). This data supports the hypothesis that thromboxanes may be involved in the development of SHR hypertension; however, alternative mechanisms are discussed.

6-Ketoprostaglandin F1 alpha

Induction of peroxisomal beta-oxidation in the rat liver in vivo and in vitro by tetrazole-substituted acetophenones: structure-activity relationships.

LY171883, a leukotriene D4 antagonist in the tetrazole-substituted acetophenone structural class, previously was demonstrated to cause peroxisome proliferation in rodents. In the present studies, several analogs were tested to determine if there are structural requirements for the induction of peroxisomal beta-oxidation in the rat liver in vivo and in cultured rat hepatocytes. Liver weight and serum triglycerides also were measured in vivo. The increases in peroxisomal beta-oxidation caused by the tetrazole-substituted acetophenones in vivo ranged from negligible to greater than 17-fold and there was good agreement with the structure-activity relationships found in cultured hepatocytes. N-methylation of the acidic nitrogen of the tetrazole blocked the peroxisomal effects, indicating that the free acid was required for activity. The length of the alkyl chain linked to the tetrazole also influenced the activity of the compounds. However, the more important determinant of peroxisomal activity may be the spatial orientation of the acidic tetrazole with respect to the planar backbone of the molecule. The data indicate there is a target site for peroxisome proliferation in the liver that is able to distinguish between structurally similar analogs. This site appears to be distinct from the leukotriene receptor since both inducers and noninducers of peroxisomal beta-oxidation were shown previously to be potent leukotriene antagonists.

Acetophenones

Inhibition of hepatic fatty acid oxidation at carnitine palmitoyltransferase I by the peroxisome proliferator 2-hydroxy-3-propyl-4-[6-(tetrazol-5-yl) hexyloxy]acetophenone.

Recent studies suggest that the induction of peroxisomal beta-oxidation in rodents may represent an adaptive response to disturbances in hepatic lipid metabolism. The following studies were done to determine the effects of 2-hydroxy-3-propyl-4-[6-(tetrazol-5-yl)hexyloxy]acetophenone (4-THA), a tetrazole-substituted acetophenone which induces peroxisomal beta-oxidation in rodent liver, on fatty acid oxidation in vitro. In isolated hepatocytes, 4-THA inhibited the oxidation of oleate (C18:1) and decreased the mitochondrial redox state. The inhibition was more pronounced in the presence of 0.2 mM-oleate than with 0.5 mM, indicating the inhibition may be competitive. 4-THA had no effect on the oxidation of octanoate (C8:0), suggesting that the site of inhibition of oleate oxidation was the carnitine-dependent transport across the mitochondrial inner membrane. In rat liver mitochondria, 4-THA inhibited carnitine palmitoyltransferase I (CPT-I) competitively with respect to the substrate palmitoyl-CoA, increasing the apparent Km from 19 microM to 86 microM. The inhibition of CPT-I by 4-THA was independent of the concentration of the co-substrate carnitine. Whereas fasting attenuated the inhibition of CPT-I by malonyl-CoA, it did not diminish the inhibition by 4-THA. Inhibition of transferase activity by 4-THA and malonyl-CoA was attenuated in mitochondria which had been solubilized with octyl glucoside to expose the latent form of carnitine palmitoyltransferase (CPT-II), suggesting that the inhibition was specific for CPT-I. The specificity was further demonstrated in studies of mitochondrial beta-oxidation in which 4-THA inhibited the oxidation of palmitoyl-CoA but not palmitoylcarnitine. The results demonstrate that 4-THA inhibits fatty acid oxidation in rat liver in vitro at the site of transport across the mitochondrial inner membrane, CPT-I. Whether this disruption in mitochondrial oxidation is causally related to the induction of peroxisomal beta-oxidation is yet to be determined.

Acetophenones

Effect of sample pretreatment on sorption of acetophenone by soils and sediments.

The effect of several sample pretreatment storage techniques, the effect of degree of grinding, and the effect or organic matter removal on the sorption of acetophenone was examined. No significant difference in the sorption of acetopheonone was observed when air-dried, freeze-dried, oven-dried, frozen, or samples kept at 2 degrees C (fresh) were compared. All pretreatment storage techniques resulted in linear sorption isotherms and gave good fits to the modified Freundlich equation (Cs = Kp . Cw). No significant differences in sorption constants (Kp) were observed for samples with a 2 mm maximum diameter when compared to samples ground to 0.6 mm maximum diameter or 0.25 mm maximum diameter. Organic matter removal resulted in decreased Kp values for samples containing more than 1% organic carbon initially but increased Kp values for samples containing less than 1% organic carbon before removal. Expandable 2:1 clay mineral content was significantly correlated with adsorption of acetophenone after organic matter removal.

Acetophenones

Metabolic N-hydroxylation of substituted acetophenone imines. I. Evidence for formation of isomeric oximes.

A series of chemically stable substituted acetophenone imines and their potential N-hydroxylated metabolites (i.e., oximes) have been synthesized and characterized by spectroscopic methods. The enzymic N-hydroxylation of acetophenone imines in vitro has been demonstrated as a general metabolic pathway in several mammalian species including the guinea-pig. The oxime metabolites were formed as mixtures of two geometric isomers, Z (syn-phenyl) and E (anti-phenyl), wherein the phenyl and hydroxyl group are cis and trans to each other respectively. The E (anti-phenyl) isomer was the quantitatively predominant isomeric form metabolically produced by all species studied. The relative proportions of the E and Z isomers in metabolic mixtures were found to be species dependent.

Acetophenones

Specific cation effect in the reaction of nitroprusside with cysteine, acetophenone and sulfite (Legal and Boedeker reaction).

The colour formation of cysteine (I), acetophenone (II) and sulfite (III) with the sodium and tetrabutylammonium (TBA) salt of nitroprusside (NP2-) in aqueous solution was studied. The intensity of colour formation depends strongly on the nature and concentration of the cations and increases in the order TBA less than Li less than Na less than K less than Rb less than Cs (in case of cysteine TBA and Li are interchanged). This specific cation effect was known for the Boedeker reaction (III) and is now also demonstrated for the Legal reaction (I and II). The adduct formation between NP2- and I to III is based on an anion-anion interaction. The role of the cation is to reduce the Coulombic repulsion between the reactants by ion-pair formation. The efficiency of ion-pair formation corresponds with the order given before except for TBA, which behaves divergently.

Acetophenones

Aldose reductase inhibitors: flavonoids, alkaloids, acetophenones, benzophenones, and spirohydantoins of chroman.

The inhibitory activity of various compounds, including 12 flavonoids, 10 alkaloids, 15 benzophenones, 5 acetophenones, and 7 spirohydantoins of chroman, was tested on rabbit lens aldose reductase, an enzyme involved in complications of diabetes. Almost all compounds tested were found to inhibit the enzyme at low concentrations (10(-5) M). The most potent inhibitor was 2R,4S-6-chloro-2-methylspiro(chroman-4,4'-imidazo-lidine+ ++)-2',5'-dione with an I50 value of 4.7 x 10(-8) M; other spirohydantoins showed similar potency. Polyhydroxybenzophenones were also potent inhibitors with an I50 value of about 10(-7) M. The possible structure-inhibitory activity relationships of the compounds tested are discussed.

Acetophenones

Alpha-(phenylselenenyl)acetophenone derivatives with glutathione peroxidase-like activity. A comparison with ebselen.

Here we describe a new class of organoselenium compounds possessing glutathione peroxidase-like activity. The parent compound, alpha-(phenylselenenyl)acetophenone (PSAP), increased the rate of reaction of glutathione with H2O2, tert-butylhydroperoxide, cumene hydroperoxide, linoleic acid hydroperoxide and dilinoleyl lecithin hydroperoxide by 7.0, 25.1, 34.1, 19.1 and 8.4-fold, respectively, as assessed by the oxidized glutathione (GSSG) reductase enzyme assay. Direct assay of the removal of hydrogen peroxide and glutathione from reaction mixtures confirmed the peroxidase-like activities of these selenoorganic compounds, but indicate that the conventional coupled GSSG reductase assay may be unsuitable for the assessment of the catalytic capacity of PSAP and Ebselen. One possible mechanism of catalysis by PSAP involves an initial oxidation at selenium. Thiol may then react with the selenoxide to yield a selenium (II) compound, H2O and a disulfide. Compounds derived from PSAP may provide potential selenium-based anti-inflammatory agents.

Acetophenones

RM values of naphthols and acetophenones in structure-activity studies.

The RM values of naphthols obtained in a chromatographic system where the stationary phase consisted of a silica gel G layer impregnated with silicone oil are much more closely related to the log P values in an octanol-water system than the RM values determined on polyamide layers. Similarly, the RM values of a series of acetophenones in the silicone system are closely related to their log P values. The equations describing the structure-activity relationship indicate the importance of lipophilic character and halogen substitution in determining the hemolytic activity and the acute toxicity of compounds.

Acetophenones