Chromium trioxide, anhydrous appears as a dark purplish red solid. Under prolonged exposure to fire or heat the containers may explode. Highly toxic. A confirmed human carcinogen.
颜色/状态:
Dark red, bipyramidal prismatic crystals, flakes or granular powder
Chromium is absorbed from oral, inhalation, or dermal exposure and distributes to nearly all tissues, with the highest concentrations found in kidney and liver. Bone is also a major storage site and may contribute to long-term retention. Hexavalent chromium's similarity to sulfate and chromate allow it to be transported into cells via sulfate transport mechanisms. Inside the cell, hexavalent chromium is reduced first to pentavalent chromium, then to trivalent chromium by many substances including ascorbate, glutathione, and nicotinamide adenine dinucleotide. Chromium is almost entirely excreted with the urine. (A12, L16)
IDENTIFICATION AND USE: Chromic trioxide is a brown solid. It is used Chromium plating, copper stripping, aluminum anodizing, corrosion inhibitor, photography, purifying oil and acetylene, hardening microscopical preparations, oxidizing agent in organic chemistry. It is also has been used as a veterinary medication. HUMAN EXPOSURE AND TOXICITY: Chronic industrial exposures have led to severe liver damage, CNS involvement and perhaps lung cancer. Allergic reactions are common. If ingested, is characterized by fulminant gastroenteritis, shock, and toxic nephritis. Chromium trioxide causes local burns. Levels of Cr VI in the form of chromium trioxide were capable of giving rise to nasal irritation at concentrations as low as 0.06 mg/cu m. In an otorhinolaryngological examination survey of 77 workers from 8 chromium-plating factories ... workers were exposed to a hexavalent chromium trioxide aerosol at levels ranging from 23-681 ug/cu m. Sixteen papillomas of the upper respiratory tract were found in 14 of the 77 workers. The authors compared this prevalence of papillomas of the oral cavity with that of other workers surveyed (10/208) and with that of clinical patients (1/40). Ulcers in 4 of 9 workers exposed to chromic trioxide mist varying from 0.18 to 1.4 mg/cu m in breathing zone have been described. In one of the cases, perforation occurred after one month of exposure. Chromosome aberration rate was significantly increased in cultured human leukocytes treated with (2 & 4 ug/mL) of chromium trioxide hexahydrate (400 & 600 ug/mL). ANIMAL STUDIES: Sarcomas (spindle-cell sarcomas and fibrosarcomas) at the implantation site were seen after 1 year in 15/35 rats implanted im with pellets of 25 mg sintered chromium trioxide. No implantation site tumors were obtained in 35 controls. A group of 43 female mice was exposed by inhalation to chromium trioxide mist (85% of particles > 5 um) generated by a miniaturized electroplating system at a chromium concentration of 1.81 mg/cu m for 120 min twice a week for 12 months, at which time 23 mice were killed. The remaining 20 were killed six months after the last exposure. Nasal perforation was seen in 3/23 and 3/20 mice killed at 12 and 18 months, respectively; 0/23 and 6/20 nasal papillomas occurred in these groups. A single lung adenoma was reported in the group killed at 18 months. No nasal inflammatory change or lung tumor was seen in a group of 20 untreated control mice. Golden hamsters received chromium(VI) trioxide iv on day 8 of pregnancy as either 5, 7.5, 10, or 15 mg/kg body weight. The dose of 15 mg/kg body weight proved to be lethal to 3/4 mother animals. The rate of resorptions increased with the higher doses (29% with 7.5 mg/kg body weight; 41% with 10 mg/kg body weight; 2% in controls), as did the rate of malformations (cleft palate, 85% at 7.5 and 10 mg/kg body weight). With the higher doses, 31% (7.5 mg/kg body weight) and 49% (10 mg/kg body weight) of the fetuses were retarded. Chromic trioxide induced high levels of chromosomal aberrations in mammalian cells. ECOTOXICITY STUDIES: Chromic trioxide inhibited kiwifruit growth and development.
Hexavalent chromium's carcinogenic effects are caused by its metabolites, pentavalent and trivalent chromium. The DNA damage may be caused by hydroxyl radicals produced during reoxidation of pentavalent chromium by hydrogen peroxide molecules present in the cell. Trivalent chromium may also form complexes with peptides, proteins, and DNA, resulting in DNA-protein crosslinks, DNA strand breaks, DNA-DNA interstrand crosslinks, chromium-DNA adducts, chromosomal aberrations and alterations in cellular signaling pathways. It has been shown to induce carcinogenesis by overstimulating cellular regulatory pathways and increasing peroxide levels by activating certain mitogen-activated protein kinases. It can also cause transcriptional repression by cross-linking histone deacetylase 1-DNA methyltransferase 1 complexes to CYP1A1 promoter chromatin, inhibiting histone modification. Chromium may increase its own toxicity by modifying metal regulatory transcription factor 1, causing the inhibition of zinc-induced metallothionein transcription. (A12, L16, A34, A35, A36)
WEIGHT OF EVIDENCE CHARACTERIZATION: Under the current guidelines (1986), Cr(VI) is classified as Group A - known human carcinogen by the inhalation route of exposure. Carcinogenicity by the oral route of exposure cannot be determined and is classified as Group D. Under the proposed guidelines (1996), Cr(VI) would be characterized as a known human carcinogen by the inhalation route of exposure on the following basis. Hexavalent chromium is known to be carcinogenic in humans by the inhalation route of exposure. Results of occupational epidemiological studies of chromium-exposed workers are consistent across investigators and study populations. Dose-response relationships have been established for chromium exposure and lung cancer. Chromium-exposed workers are exposed to both Cr(III) and Cr(VI) compounds. Because only Cr(VI) has been found to be carcinogenic in animal studies, however, it was concluded that only Cr(VI) should be classified as a human carcinogen. Animal data are consistent with the human carcinogenicity data on hexavalent chromium. Hexavalent chromium compounds are carcinogenic in animal bioassays, producing the following tumor types: intramuscular injection site tumors in rats and mice, intrapleural implant site tumors for various Cr(VI) compounds in rats, intrabronchial implantation site tumors for various Cr(VI) compounds in rats and subcutaneous injection site sarcomas in rats. In vitro data are suggestive of a potential mode of action for hexavalent chromium carcinogenesis. Hexavalent chromium carcinogenesis may result from the formation of mutagenic oxidatitive DNA lesions following intracellular reduction to the trivalent form. Cr(VI) readily passes through cell membranes and is rapidly reduced intracellularly to generate reactive Cr(V) and Cr(IV) intermediates and reactive oxygen species. A number of potentially mutagenic DNA lesions are formed during the reduction of Cr(VI). Hexavalent chromium is mutagenic in bacterial assays, yeasts and V79 cells, and Cr(VI) compounds decrease the fidelity of DNA synthesis in vitro and produce unscheduled DNA synthesis as a consequence of DNA damage. Chromate has been shown to transform both primary cells and cell lines. HUMAN CARCINOGENICITY DATA: Occupational exposure to chromium compounds has been studied in the chromate production, chromeplating and chrome pigment, ferrochromium production, gold mining, leather tanning and chrome alloy production industries. Workers in the chromate industry are exposed to both trivalent and hexavalent compounds of chromium. Epidemiological studies of chromate production plants in Japan, Great Britain, West Germany, and the United States have revealed a correlation between occupational exposure to chromium and lung cancer, but the specific form of chromium responsible for the induction of cancer was not identified ... Studies of chrome pigment workers have consistently demonstrated an association between occupational chromium exposure (primarily Cr(VI)) and lung cancer. Several studies of the chromeplating industry have demonstrated a positive relationship between cancer and exposure to chromium compounds. ANIMAL CARCINOGENICITY DATA: Animal data are consistent with the findings of human epidemiological studies of hexavalent chromium ... /Chromium (VI)/
Evaluation: There is sufficient evidence in humans for the carcinogenicity of chromium(VI) compounds. Chromium(VI) compounds cause cancer of the lung. Also positive associations have been observed between exposure to Chromium(IV) compounds and cancer of the nose and nasal sinuses. There is sufficient evidence in experimental animals for the carcinogenicity of chromium(VI) compounds. Chromium(VI) compounds are carcinogenic to humans (Group 1). /Chromium(VI) compounds/
来源:Hazardous Substances Data Bank (HSDB)
毒理性
致癌性证据
铬 hexavalent 化合物:已知是人类致癌物。/铬 hexavalent 化合物/
Chromium Hexavalent Compounds: known to be human carcinogens. /Chromium hexavalent compound/
Pyrazoloquinolinone derivatives as protein kinase C inhibitors
申请人:——
公开号:US20030130277A1
公开(公告)日:2003-07-10
This invention provides a compound of the formula (I):
1
or the pharmaceutically acceptable salts thereof wherein the dashed lines represent optional double bonds; C
1
, C
2
, C
3
and C
4
are carbon atom; R
1
is C
1-4
alkyl ; R
2
is H, amino, etc.; R
3
is H, halo-CH
2
—, C
2-8
alkyl or Q
1
-, wherein said C
2-8
alkyl is optionally substituted with up to 3 substituents selected from halo, C
1-3
alkyl, R
4
(R
5
)N, etc.; R
4
is H, C
1-7
alkyl, etc.; R
5
is H, C
1-7
alkyl, etc. ; R
6
and R
7
are independently selected from H and C
1-4
alkyl ; R
8
is aryl or heteroaryl ; Q
1
is a 4-12 membered monocyclic or bicyclic aromatic, partially saturated or fully saturated ring optionally containing up to 4 heteroatoms selected from O, N and S, and is optionally substituted with halo, C
1-4
alkyl, etc. ; Y
5
, Y
6
, Y
7
and Y
8
are hydrogen ; Y
1
, Y
2
, Y
3
and Y
4
are independently selected from hydrogen, halo, etc.; Q
2
is a 5-12 membered monocyclic or bicyclic aromatic, partially saturated or fully saturated ring optionally containing up to 3 heteroatoms selected from O, N and S, and is optionally substituted with halo, C
1-4
alkyl-, etc.;
These compounds have protein kinase C inhibitory activity and thus are useful for the treatment of neuropathic pain, acute or chronic inflammatory pain, auditory deficiency (synaptic repair), or the like in mammalian, especially humans. This invention also provides a pharmaceutical composition comprising the above compound.
The invention provides compounds of general formula (I) wherein Q, R, R
2
, R
4
, R
5
, R
6
, R
7
and R
8
are as defined in the specification, processes for their preparation, pharmaceutical compositions containing them and their use in therapy.
The kinetics of oxidation of allylalcohol by quinaldinium chlorochromate is investigated in 40 % acetic acid – water (v/v) medium. The order with respect to oxidant and hydrogen ion concentration is found to be one and fractional with respect to substrate. The rate of the reaction is decreases with the decrease in the dielectric constant of the medium. The rate of the reaction has negligible effect
Azolobenzazepine derivatives as neurologically active agents
申请人:Zeneca Limited
公开号:US06124281A1
公开(公告)日:2000-09-26
The invention relates to azolobenzazepine derivatives of formula (I), wherein: X is O or S; R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently hydrogen, perfluorolower-alkyl, halogen, nitro or cyano; and C together with the carbon atoms to which it is attached forms a 5-membered aromatic heterocycle selected from the group consisting of a pyrazol and triazole, to pharmaceutical compositions containing them and to methods for the treatment of neurological disorders utilizing them. ##STR1##
Process for the preparation of 6-(perfluoroalkyl) uracil compounds from
申请人:American Cyanamid Company
公开号:US06140270A1
公开(公告)日:2000-10-31
An improved process for the preparation of 6-(perfluoroalkyl)uracil compounds having the structural formula I ##STR1## from 2-(N,N-disubstituted)amino-4-(perfluoroalkyl)-1,3-oxazin-6-one compounds having the structural formula II ##STR2##