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PubMed1997

2,6-Bis((3,4-dihydroxyphenyl)-methylene)cyclohexanone (BDHPC)-induced apoptosis and p53-independent growth inhibition: synergism with genistein.

Estrogen binds to two classes of proteins in the cells, the high-affinity estrogen receptor (ER) as well as a low affinity estrogen type II binding site (EBS-II). Methyl p-hydroxyphenyllactate (MeHPLA) is an endogenous ligand for EBS-II. Binding of MeHPLA to EBS-II has a growth regulatory effect in estrogen-responsive cells, and levels of MeHPLA are decreased in breast cancer due to degradation by a specific esterase. 2,6-bis((3, 4-dihydroxyphenyl)-methylene) cyclohexanone (BDHPC) is an esterase-resistant analogue of MeHPLA which binds irreversibly to EBS-II and inhibits growth of breast cancer cells. In the present study, we analyzed the mechanism of growth inhibition by BDHPC. Treatment with BDHPC resulted in accumulation of cells in G1 phase and apoptosis. The G1 accumulation was not dependent on a functional p53 gene. The G1-specific growth inhibition by BDHPC was found to act synergistically with the G2/M-specific inhibition induced by the tyrosine kinase inhibitor genistein, suggesting this drug combination could be effectively used in cancer treatment.

Antineoplastic Agents↗
PubMed1994

Uptake, metabolism and elimination of cyclohexanone in humans.

The metabolism and toxicokinetics of cyclohexanone (CH-one), an important solvent and chemical intermediate, have been studied in volunteers during and after 8-h exposures to CH-one vapour at a concentration of 101, 207 and 406 mg.m-3. The pulmonary ventilation in these experiments was typically 11 l.min-1 and retention in the respiratory tract was 58%. After exposure to CH-one, 207 mg.m-3, the metabolic yields of cyclohexanol (CH-ol), 1,2- and 1,4-cyclohexanediol (CH-diol) as determined in urine by a gas chromatographic method involving hydrolysis of glucuronide conjugate were 1.0% +/- 0.3%, 39% +/- 5% and 18% +/- 2% (n = 8), respectively. Peak excretion of CH-ol was achieved at the end of the exposure period, after which it decayed rapidly. Elimination of 1,2- and 1,4-CH-diol reached maximum values a few hours following exposure, with subsequent elimination half-times of 16 +/- 2 and 18 +/- 4 h, respectively. Repeated exposure to CH-one vapour (around 200 mg.m-3) for five consecutive days (8 h/day) resulted in cumulative excretion of CH-diols. The permeation rate of CH-one liquid through the skin was 0.037-0.069 mg.cm-2.h-1 (n = 3), indicating that the contribution of percutaneous absorption to total CH-one occupational intake is of minor importance. CH-diols are recommended as biomarkers of exposure to CH-one.

Administration, Cutaneous↗
PubMed1998

1,2- and 1,4-Cyclohexanediol: major urinary metabolites and biomarkers of exposure to cyclohexane, cyclohexanone, and cyclohexanol in humans.

The metabolism and toxicokinetics of cyclohexane (CH) and cyclohexanol (CH-ol), important solvents and chemical intermediates, were studied in volunteers after 8-h periods of inhalation exposure at concentrations of 1010 and 236 mg m(-3), respectively (occupational exposure limits: CH, 1050 mg m(-3); CH-ol, 200 mg m(-3)). Of the dose of absorbed parent compounds, the yields of urinary CH-ol and 1,2- and 1,4-cyclohexanediol (CH-diol) were 0.5%, 23.4%, and 11.3%, respectively, after exposure to CH and 1.1%, 19.1%, and 8.4%, respectively, after exposure to CH-ol as determined by a gas chromatography method involving hydrolysis of glucuronide conjugates. The metabolic patterns of CH and CH-ol were very similar to that of cyclohexanone (CH-one) studied in the laboratory previously. For all three compounds, peak excretion of CH-ol occurred at the end of the exposure period, after which it decayed rapidly. Excretion curves of 1,2- and 1,4-CH-diol reached maximal values within 0-6 h postexposure, with subsequent elimination half-lives being 14-18 h. The rate-limiting step in the elimination of CH compounds from the organism is renal clearance of CH-diols. Determination of CH-diols in end-of-shift urine samples is recommended as a useful new method of biomonitoring of CH, CH-ol, and CH-one at the workplace. However, due to accumulation of CH-diols in the body during repeated exposure, quantitative relationships between the exposure and the level of CH-diols have to be adjusted according to the day of sampling during the working week.

Adult↗
PubMed1985

Effects of (1,6-di(O-carbamoyl)cyclohexanone oxime)hexane (RHC 80267) on prostaglandin biosynthesis and accumulation of diacylglycerol and arachidonic acid in rabbit iris.

The effects of RHC 80267, (1-6-di(O-carbamoyl)cyclohexanone oxime)hexane, a diacylglycerol (DG) lipase inhibitor, on the DG lipase pathway and on arachidonic acid (AA) metabolism were investigated in the iris muscle. Incubation of the iris for 30 min at 37 degrees resulted in a loss of AA from phosphatidylinositol, phosphatidylcholine, and phosphatidylethanolamine of 40, 25, and 32% respectively. It was found that the drug inhibited the activity of DG lipase in the iris microsomal fraction and it increased the accumulation of DG, AA and other glycerolipids in iris muscle prelabeled with [14C]AA, presumably by inhibiting this enzyme. Under the same experimental conditions, the drug increased the accumulation of DG and AA in the tissue in a dose- and time-dependent manner, and it inhibited the synthesis of prostaglandin E2 (PGE2) and PGF2 alpha by iris and iris microsomes in a dose-dependent manner. The data presented indicate that RHC 80267 has nonspecific effects on glycerolipid and AA metabolism in this tissue. We conclude that, while the drug does inhibit DG lipase in the intact iris, the present findings that it increased the accumulation of glycerolipids and AA and that it inhibited the biosynthesis of PGs in this tissue throw some doubt on its use in studies on the mechanism of AA release from membrane phosphoinositides for PG synthesis.

Animals↗
PubMed1985

Toxicity of cyclohexanone oxime. I. Hematotoxicity following subacute exposure in rats.

Cyclohexanone oxime (CHO) was given po to male and female Fischer 344 rats at dose levels of 10, 25, 75, 150, and 300 mg/kg, five times a week for a period of 2 weeks. Control animals received distilled water. All animals given intermediate dose levels (10, 25, 75, and 150 mg/kg) and one half of the animals which were dosed at the high dose (300 mg/kg) as well as one half of the controls were terminated 14 days after administration of the first dose. The remaining rats received no treatment for an additional 14 days and were sacrificed on Day 28 of the study (recovery phase). Dose-related decreases in erythrocyte number, hemoglobin, and hematocrit, with an accompanying increase in reticulocytes and circulating nucleated erythrocytes, were observed in both sexes at Day 14. Methemoglobin levels, determined only at the high dose, were elevated in both sexes at this time. Splenomegaly and hepatomegaly were observed in both sexes at 14 and 28 days. Histopathological examination of the spleen and bone marrow revealed dose-related erythroid hyperplasia at 14 days which subsided by Day 28. The above effects were more pronounced in males. Erythrocyte numbers were only slightly depressed and reticulocytes mildly elevated in males at Day 28. Hematological values were not statistically different from controls in females at this time. These results suggest that CHO induces oxidative damage to the erythrocyte, resulting in a hemolytic anemia accompanied by increased erythropoiesis. The toxic effects appear reversible upon cessation of exposure.

Anemia, Hemolytic↗
PubMed1985

Toxicity of cyclohexanone oxime. II. Acute dermal and subchronic oral studies.

Dermal exposure of rabbits to cyclohexanone oxime (CHO) for 24 hr at 0, 0.8, 2, and 5 g/kg caused dose-related reticulocytosis on the day after dosing as well as a decrease in hemoglobin in the 5-g/kg females 7 days postdosing. Gavage of rats 5 days a week for 13 weeks at levels of 0, 0.25, 2.5, and 25 mg/kg resulted in a dose-related decrease in erythrocyte number, hemoglobin, and hematocrit, with an accompanying increase in circulating reticulocytes and nucleated erythrocytes, in both sexes. Also seen were corneal opacities and an increased incidence of Howell-Jolly bodies. Results suggested an increased erythropoiesis in the spleen and bone marrow. The data from satellite groups terminated at 30 and 60 days revealed no effect at the lower test level, but results from the end of the study showed a clear cumulative dose response down to the 0.25-mg/kg level. Males were affected earlier and at lower doses than females. These results, along with those of a subacute study with a recovery period, suggest that CHO induces an oxidative attack on erythrocytes which appears reversible upon cessation of exposure.

Administration, Oral↗
PubMed2001

Preparation of novel polysubstituted chiral cyclohexanone derivatives containing a quaternary carbon by Ferrier reaction.

2-C- and 3-C-[(2'-chloro)pyrid-5'-yl]-hex-5-enopyranosides were synthesized from 4,6-O-benzylidene acetals in three steps. By treatment with mercury or palladium salts, the corresponding cyclohexanones could be obtained. The stereochemistry of these reactions was highly dependent on the substitution pattern of the starting material and the nature and concentration of the catalyst.

Catalysis↗
PubMed2000

Cytotoxic 2,6-bis(arylidene)cyclohexanones and related compounds.

A number of 2-arylidenecyclohexanones 1, 2, 6-bis(arylidene)cyclohexanones 2 and related Mannich bases 3-5 were prepared. Various torsion angles as well as atomic charges on olefinic carbon atoms were determined by molecular modelling on all compounds. These molecules showed cytotoxicity towards murine P388 and L1210 cells as well as to human Molt 4/C8 and CEM T-lymphocytes. The average cytotoxicity of the dienones 2 was more than three times greater than was found with the monoarylidene analogues 1, and, in general, were slightly more cytotoxic than the Mannich bases 3-5. A number of the compounds displayed potency towards a panel of human tumour cell lines and most of the representative compounds in series 2-5 were selectively toxic to colon cancers and leukaemic cells.

Animals↗
PubMed1998

Simultaneous determination of airborne acetaldehyde, acetone, 2-butanone, and cyclohexanone using sampling tubes with 2,4-dinitrophenylhydrazine-coated solid sorbent.

The 2,4-dinitrophenylhydrazine (2,4-DNPH) derivatization method mainly used for the determination of airborne formaldehyde was extended for acetaldehyde, acetone, 2-butanone, and cyclohexanone, the next four carbonyl compounds of industrial importance. Sampling devices and sampling conditions were adjusted for the respective limit value regulations. Analytical reliability criteria were established and compared to those of other recommended methods. With a minimum analytical range from one tenth to the 3-fold limit value in all cases and with relative standard deviations below 5%, the adjusted method meets all requirements for the reliable quantification of the four compounds in workplace air as well as in ambient air.

Acetaldehyde↗
PubMed2005

Hierarchically structured monolithic silicalite-1 consisting of crystallized nanoparticles and its performance in the Beckmann rearrangement of cyclohexanone oxime.

In this study, we present a synthetic pathway for the fabrication of self-supporting zeolite monoliths consisting of crystallized nanoparticles. A resorcinol-formaldehyde-based organic aerogel is used as a template, and silicalite-1 is used as the zeolite example. The silicalite-1 monoliths obtained consist of individual well-defined zeolite nanocrystals with sizes of 30-40 nm. The monoliths exhibit a high mechanical stability and have hierarchical porosity, with micropores within the zeolite particles, a mesopore system formed by the packing of the nanoparticles, and a macropore system on the monolith level. Such monolithic zeolites show high selectivity typically above 80% to epsilon-caprolactam combined with a high rate of reaction of 0.46 g(caprolactame)/(g(catalyst).h) in the Beckmann rearrangement of cyclohexanone oxime.

Carbon↗
PubMed2000

Sequential cytotoxicity: a theory evaluated using novel 2-[4-(3-aryl-2-propenoyloxy)phenylmethylene]cyclohexanones and related compounds.

Five series of novel compounds were synthesized in order to evaluate the theory of sequential cytotoxicity which seeks to exploit the view that various cancer cells are particularly susceptible to successive attacks by cytotoxic agents. The compounds prepared were various 2-[4-(3-aryl-2-propenoyloxy)phenylmethylene]cyclohexanone s 1 and the related Mannich bases 2. In addition the analogues 3-5 lacking an olefinic bond in the ester group were also synthesized, which were predicted to be less cytotoxic than the compounds of series 1 and 2. The atomic charges at the potential sites for interaction with cellular constituents were determined by molecular modeling calculations. The biodata obtained from murine and human neoplastic cells revealed that the predictions made regarding the viability of the theory were fulfilled in approximately two-thirds of the cases indicating that further investigation of this hypothesis is warranted. In addition, the significant potencies of some of the Mannich bases toward human tumor cell lines, in particular coupled to their selective toxicity toward human leukemic and colon cancer cells, confirms their usefulness in serving as lead molecules for further development. A preliminary investigation into the mode of action of representative compounds revealed their ability to induce apoptosis and inhibit the biosyntheses of ribonucleic acid and proteins.

Animals↗
PubMed2006

Nucleophilic substitution reactions of sulfur-substituted cyclohexanone acetals: an analysis of the factors controlling stereoselectivity.

The reactions of cyclohexanone acetals substituted with thiophenyl groups (and other heteroatoms) at C-2 demonstrate the powerful influence that these substituents have on the stereoselectivity of nucleophilic substitution reactions. The trans selectivities of these reactions correlate with the behavior of the corresponding ketones. These experiments lend support to the possibility that the reactions of the acetals, which proceed via oxocarbenium ions, are operating under Felkin-Anh control.

Acetals↗
PubMed2006

Electrostatic effects on the reactions of cyclohexanone oxocarbenium ions.

Nucleophilic substitution reactions of 4-substituted cyclohexanone acetals display different selectivities depending upon the electronic nature of the substituent. Alkyl groups favor equatorial positions in the oxocarbenium ions, but alkoxy groups prefer axial conformers. The reactions of acetals with alkoxy groups constrained to either equatorial or axial positions suggest that the presence of an axial alkoxy group distorts the oxocarbenium ion, changing its inherent preferences for facial attack.

Acetals↗
PubMed2000

Stereochemistry of the oxidation of imines derived from substituted cyclohexanones: axial vs equatorial attack and evidence for delivery by an adjacent hydroxyl group.

A set of conformationally biased imines derived from substituted cyclohexanones and benzylamine or diphenylmethylamine, respectively, were oxidized to the corresponding oxaziridines. The structures of the oxaziridines were determined via NMR comparison of two series of differently N-substituted oxaziridines. Thus, those compounds having an axially disposed nitrogen substituent displayed an upfield-shifted axial proton in a 1,3-relationship to the oxaziridine nitrogen in the N-diphenylmethyl series relative to the N-benzyl compounds. Analysis of the products obtained from these reactions suggests that (1) adjacent hydroxyl groups favor syn oxidant addition and (2) imines containing adjacent methoxy groups preferentially undergo attack anti to the resident alkoxy substituent.

Cyclohexanones↗
PubMed2005

Rapid access to the Welwitindolinone alkaloid skeleton by cyclization of indolecarboxaldehyde substituted cyclohexanones.

[reaction: see text] A very rapid access to cyclohexanone-bridged indole systems was established by an acid-mediated ring closure of appropriately substituted indole aldehydes, which involved an apparent disproportionation of an aldol-like intermediate. One of the bridged indole intermediates was further transformed into an oxindole having the essential skeleton of the Welwitindolinone alkaloids.

Aldehydes↗
PubMed2007

Alpha,alpha'-annulation of 2,6-prenyl-substituted cyclohexanone derivatives with malonyl chloride: application to a short synthesis of (+/-)-clusianone. Formation and rearrangement of a biogenetic-like intermediate.

Conditions were found for the successful Effenberger alpha,alpha'-annulation of 3,3-dimethyl-2,4,6-triprenyl cyclohexanone silyl enol ethers with malonyl chloride to give the corresponding bicyclo[3.3.1]nonane-trione in 35% yield, this result allowing a short synthesis of (+/-)-clusianone. An isomeric rearranged bicyclo[3.3.1]nonane-trione was also isolated in 25% yield, and changing the Lewis acid resulted in formation of a lavandulyl-substituted phloroglucinol derivative in 38% yield. The mechanism of formation of these two last products mimics the biogenetic pathway to PPAPs. [reaction: see text].

Benzophenones↗