PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Fluorenes”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMedDate not supplied

The catalytic effect of bovine serum albumin on the ortho rearrangement of the potential ultimate carcinogen, N-(sulfooxy)-2-(acetylamino)fluorene, generated enzymatically from N-hydroxy-2-(acetylamino)fluorene and evidence for substrate specificity of the enzymatic sulfonation of arylhydroxamic acids.

This investigation examines the catalytic effect of bovine serum albumin on the ortho rearrangement of the possible ultimate carcinogen, N-(sulfooxy)-2-(acetylamino)fluorene, generated from N-hydroxy-2-(acetylamino)fluorene by the sulfotransferase(s) in the cytosol of rat liver. With various preparations of cytosol, 55-75% of the substrate, N-hydroxy-2-(acetylamino)-fluorene, was found to rearrange to the nonmutagenic and noncarcinogenic o-(sulfooxy) esters, 1- and 3-(sulfooxy)-2-(acetylamino)fluorene, in the presence of bovine serum albumin, while less than 1% of the substrate rearranged in its absence. In presence of bovine serum albumin the cytosolic reduction of N-(sulfooxy)-2-(acetylamino)fluorene to 2-(acetylamino)fluorene decreased by 60-90% and its solvolytic degradation to 4-hydroxy-2-(acetylamino)fluorene by 80-90%. The covalent interaction of enzymatically generated N-(sulfooxy)-2-(acetylamino)fluorene with the nucleophilic acceptors, N-acetyl-L-methionine and guanosine, was lowered by greater than 90% by addition of bovine serum albumin. These measurements indicated that the albumin-catalyzed ortho rearrangement controls the rates of concurrent metabolic and degradative reactions of N-(sulfooxy)-2-(acetylamino)fluorene. The results are in agreement with previous findings of a catalytic effect of serum albumin on the ortho rearrangement of synthetic N-(sulfooxy)-2-(acetylamino)fluorene. In contrast to its catalytic effect on the formation of o-(sulfooxy) esters from N-(sulfooxy)-2-(acetylamino)fluorene, bovine serum albumin had no effect on the formation of o-(acetylamino)fluorenols. To assess the substrate specificity of bovine serum albumin, its effect on the rearrangement of N-hydroxy-2-(benzoylamino)fluorene, a carcinogenic analogue of N-hydroxy-2-(acetylamino)fluorene, was analyzed under conditions of cytosolic sulfonation.(ABSTRACT TRUNCATED AT 250 WORDS)

2-Acetylaminofluorene↗
PubMedDate not supplied

Metabolism of alcohol and ketone by cytochrome P-450 oxygenase: fluoren-9-ol in equilibrium with fluoren-9-one.

Fluoren-9-ol and fluoren-9-one were used as model substrates to study microsomal metabolism of alcohols and carbonyl compounds. It was found that there was an oxidoreductase(s) present in the microsomal preparation that catalyzed interconversion of this alcohol and ketone using pyridine nucleotides as cofactors. The alcohol could also be oxygenated to the ketone by microsomes and NADPH. It required molecular oxygen. This oxygenation was inhibited by SKF 525-A and CO, suggesting the involvement of P-450 oxygenase. Using highly purified P-450 oxygenase components, it was shown that fluoren-9-ol was oxygenated by the complete system to fluoren-9-one. Exclusion of cytochrome P-450 or its reductase resulted in no oxygenation. Dilauroylglyceryl-3-phosphorylcholine was without effect on the reaction. Fluoren-9-one, on the other hand, was reduced to fluoren-9-ol by NADPH-cytochrome P-450 reductase and NADPH. It is suggested that other alcohols and carbonyl compounds are similarly metabolized.

Alcohols↗
PubMed1995

Transformation of Substituted Fluorenes and Fluorene Analogs by Pseudomonas sp. Strain F274.

Pseudomonas sp. strain F274, previously shown to catabolize fluorene via fluorenone and its angular dioxygenation, 2(prm1),3(prm1)-dihydroxy-2-carboxybiphenyl, phthalate, and protocatechuate, was examined for its ability to transform substituted fluorenes and S- and N-heterocyclic analogs. Halogen- and methyl-substituted fluorenes were metabolized to correspondingly substituted phthalates via attack on the unsubstituted ring. In the case of 1-methylfluorene, initial oxidation of the methyl group to carboxyl prevented all other transformations but 9-monooxygenation. This strain also oxidized the S-heteroatoms and benzylic methylenic groups of fluorene analogs. No angular dioxygenation of S- and N-heterocycles was observed.

Journal Article↗
PubMedDate not supplied

Modification of alveolar macrophage function with bis-basic ethers of fluorene and fluoren-9-substituted derivatives.

Bis-basic ethers of fluorene and fluoren-9-substituted derivatives such as tilorone have been reported to inhibit silica-induced fibrosis in rats. The potential antifibrotic potency of 2,7-bis(diethylamino)ethoxy fluorene (F-9-H,H), fluorenone (F-9-one), fluorenoxime (F-9-oxime), and fluorenol (F-9-ol) was F-9-oxime > F-9-one approximately F-9-H,H >> F-9-ol. Since the release of reactive oxygen species and growth factors from alveolar macrophages (AM) in response to silica exposure has been linked to the development of pulmonary fibrosis, the present study was carried out to determine the inhibitory effects of these compounds on rat AM activity in vitro. The following parameters were monitored: (1) cellular viability; (2) zymosan-induced respiratory burst activity (superoxide and hydrogen peroxide release, chemiluminescence, and oxygen consumption) of AM; (3) drug binding to AM; and (4) lipopolysaccharide (LPS)-stimulated interleukin-1 (IL-1) release from AM. The bis-basic ethers, at 40 microM, did not affect cell viability when incubated with AM for 30 min, but significantly inhibited zymosan-induced macrophage respiratory burst activity. The inhibitory effect of these agents was F-9-oxime > F-9-one approximately F-9-H,H >> F-9-ol. Binding of these drugs to AM was time and dose dependent, and exhibited the following binding affinity: F-9-oxime > F-9-one > F-9-H,H > F-9-ol. F-9-oxime was shown to inhibit LPS-stimulated IL-1 release by AM in a dose-dependent manner. This inhibition of IL-1 release by AM cannot be explained as a decrease in viability. In addition, these drugs were also shown to impair human fibroblast proliferation in response to serum stimuli without impairing cell viability. These results indicate a positive correlation between drug binding to AM or other cell types and their inhibitory effects on cellular activities including oxygen consumption, superoxide release, hydrogen peroxide secretion, chemiluminescence, IL-1 release, and proliferation. The ability of these bis-basic ethers to modify AM and fibroblast functions in vitro suggests that further investigation of their reported antifibrotic potency in vivo is warranted.

Animals↗
PubMed2002

Radical cation and dication of fluorene fully annelated with bicyclo[2.2.2]octene units: importance of the quinoidal resonance structure in the cationic fluorene.

Fluorene 1 fully annelated with bicyclo[2.2.2]octene units was newly synthesized and oxidized to stable cationic species. The structure of radical cation salt 1(.+)SbCl(6)(-) was determined by X-ray crystallography, while the first fluorene dication 1(2+) was characterized by (1)H and (13)C NMR at -80 degrees C. Combined with the results of theoretical calculations, an important contribution of a quinoidal structure to the resonance hybrid was demonstrated in both 1(.+) and 1(2+). [structure: see text]

Journal Article↗
PubMed2000

Unexpected dipivaloylation of 9-lithiated fluorene: formation of 1-(fluoren-9-ylidene)-2,2-dimethylpropyl pivalate.

Treatment of 9-lithiated fluorene with pivaloyl chloride provided ap-9-pivaloylfluorene, (1), the major product, and a minor product ultimately identified as the title compound, C(23)H(26)O(2), (2). The latter was also formed directly, but slowly, from 9-lithiated-(1) treated with pivaloyl chloride. Although (1) exists exclusively as its less sterically restricted ap rotamer, its sp(2)-hybridized anion sterically impedes reaction at the 9-position from either face. While 9-lithiated-(1) is exclusively, but slowly, 9-methylated with methyl iodide, reaction with pivaloyl chloride, also slow, leads only to the O-acylated product, (2). The protons of the tert-butyl-C=C moiety approach a proton on the fluorene ring to well within the sum of their van der Waals radii, resulting in significant molecular compression, strain and distortion. For example, distortion in the moiety C=C(O)(C) is exhibited by the enlargement of C=C-C angle to 130.6 (2) degrees at the expense of the corresponding 'equivalent' C=C-O angle, which is compressed to 116.46 (19) degrees.

Journal Article↗
PubMed2001

Dispiro[fluorene-9,5'-[1,2,3,4]tetrathiane-6',9"-fluorene.

The tetrathiane ring of the title compound, C26H16S4, has a chair conformation and the molecule has approximate C2 symmetry. Each of the two fluorene ring systems is virtually planar, with the ring planes intersecting at an angle of 67.58 (5) degrees. This novel compound has been formed as a side product from the treatment of 9H-fluorene-9-thione with methyl N-[(benzylidene)phenyl]glycinate in the presence of LiBr and 1,6-diazabicyclo[5.4.0]undecane.

Journal Article↗
PubMed1985

Derivatives of benzo(c)fluorene. XVI. Absorption, distribution and elimination of 3H-benflurone, 5-(2-N,N-dimethylamino)ethoxy)-7-oxo-7H-benzo(c)fluorene hydrochloride in rats after oral and intravenous administration.

3H-benfluorone administered orally to rats, persists for a long time in the stomach; it is absorbed only partly and eliminated mostly through the feces (about 80% within 7 days). The maximum levels in the blood and the organs were determined in the 1st and 9th hour after application. Benflurone penetrates through the placentary barrier. Within one week 13% of the administered radioactivity was eliminated through the urine and 8% through the bile within 12 h. It has been demonstrated that benflurone was excreted through the milk, as well. After being administered intravenously, benflurone moves quickly from the blood into the tissues. The high levels were recorded in the heart, the lungs, the kidneys, the brain and the liver. After intravenous application about 70% of the administered radioactivity was eliminated within one week through the feces and about 24% through the urine, almost 54% through the bile within 12 h.

Administration, Oral↗
PubMed2004

Dimerization of 9-phenylethynylfluorene to di-indeno-naphthacene and dispiro-[fluorene-dihydronaphthacene-fluorene]: an X-ray crystallographic and NMR study.

The attempted Diels-Alder reaction between 9-phenylethynylfluorene and tetracyclone yields instead three products resulting from the dimerization of the isomeric allene. The major product is 8,16-diphenyl-diindeno[1,2,3-de:1',2',3'-mn]naphthacene, in which each terminal ring is derived from a fluorenyl unit; aerial oxidation then yields a peroxide. A dihydronaphthacene bearing fluorenyl moieties spiro-bonded at the C(5) and C(11) positions was also identified. The structures of the naphthacenes were elucidated by X-ray crystallography, and a mechanistic rationale is offered. [reaction: see text]

Journal Article↗