1,2-dichloroethylene, (mixed isomers) appears as a clear colorless liquid with ether-like odor. Mixture of cis and trans isomers. Flashpoint 36 - 43° F. Denser than water and insoluble in water. Vapors heavier than air.
颜色/状态：
Colorless liquid (usually a mixture of the cis- and trans-isomers) ...
Hazardous polymerization may occur. Polymerization may be caused by elevated temperature, oxidizing materials, peroxides, or sunlight. Usually contains inhibitors to prevent polymerization. Uninhibited monomer vapor may form polymer in vents and other confined spaces.
Numerous xenobiotics are known to be bioactivated and to covalently bind to proteins, but the resulting amino acid adducts are unknown. In this study, the amino acid adducts of 12 (14)C-labeled aliphatic halides were examined after formation in an in vitro rat hepatic microsomal system. After exhaustive solvent extraction of the polypeptide microsomal protein, the amino acid adducts were isolated by Pronase digestion, followed by filtration through a 500 mol-wt exclusion membrane. 1,2-Dichloroethylene had a single major amino acid adduct. ...
Incubation of rat liver microsomes with 1,2-dichloroethylene caused a fall in microsomal cytochrome p450 content (as determined by measuring the oxidation of reduced nicotinamide adenine dinucleotide at 340 nm), without affecting other microsomal enzymes. The decrease in cytochrome p450 occurred only in the presence of reduced nicotinamide adenine dinucleotide, suggesting that the dichloroethylene must be metabolized to exert its destructive action. The loss of cytochrome p450 was probably due to destruction of heme, since the fall in cytochrome p450 was always accompanied by a parallel decrease in microsomal heme content.
Metabolism of 1,2-DCE is initially catalyzed by hepatic CYP450 ... . Studies suggest that the metabolism of 1,2-DCE involves epoxidation of the ethylene double-bond, forming dichlorinated epoxides, which can undergo a nonenzymatic rearrangement and produce several metabolites. Following rearrangement of the intermediate epoxide, reduction of the resulting dichloroacetaldehyde to dichloroethanol may be catalyzed by alcohol dehydrogenase (ADH). Studies ... provide evidence that dichloroacetaldehyde is the predominant metabolite of CYP450, which is extensively converted to dichloroethanol and dichloroacetate by dehydrogenases present in hepatocytes. Oxidative dechlorination of the minor metabolite, dichloroacetic acid (DCA), to glyoxylate is catalyzed by glutathione S-transferase zeta (GSTZ).
IDENTIFICATION AND USE: 1,2-Dichloroethylene (DCE) is a colorless mobile liquid. It is used as a refrigerant, in the manufacture of pharmaceuticals and artificial pearls, and in the extraction of oils and fats from fish and meat. It is also a solvent for fats, phenol, camphor, and an intermediate in synthesis of chlorinated solvents and compounds. HUMAN STUDIES: Clinical effects caused by acute exposure to DCE include central nervous system and respiratory depression, eye and upper respiratory irritation, nausea, vomiting, weakness, tremors, and epigastric cramps, all of which may resolve rapidly after the exposure ceases. The investigation of workers exposed to DCE indicated that prematurities among exposed female workers and wives of exposed male workers were higher than that of control groups. The DNA breakage capacity and the cytotoxicity of DCE was assessed in the alkaline single cell gel electrophoresis test (comet assay) with and without metabolic activation in isolated human lymphocytes. DCE induced DNA breakage, in the presence or absence of the metabolic activation system. ANIMAL STUDIES: Some but not all dogs experienced CNS depression by inhaling the DCE vapor and have developed delicate superficial corneal turbidity. A subchronic inhalation study was conducted in which rats, rabbits, guinea pigs, and beagle dogs were exposed to 0, 500, or 1,000 ppm (0, 1,980, or 3,960 mg/cu m) DCE mixture (58% cis-, 42% trans- isomer), 7 hours/day for 6 months. No significant toxicity was found. Behavioral changes have been observed in mice exposed for 4 hr to DCE. The reported changes consisted of a dose-related decrease in the duration of immobility in the "behavioral despair" swimming test. A 45% decrease in the total duration of immobility occurred at a concentration of 1,720 ppm. Gonadotoxicity and embryotoxicity were found in rodents exposed to concentration of DCE at 24.8 mg/cu m. DCE could reach the fetus through the placenta. Cis,trans-DCE was found to be negative when tested for mutagenicity using the Salmonella/microsome preincubation assay in as many as 5 Salmonella typhimurium strains (TA1535, TA1537, TA97, TA98, and TA100) in the presence and absence of metabolic activation.
来源:Hazardous Substances Data Bank (HSDB)
毒理性
暴露途径
该物质可以通过吸入其蒸汽和摄入进入人体。
The substance can be absorbed into the body by inhalation of its vapour and by ingestion.
来源:ILO-WHO International Chemical Safety Cards (ICSCs)
毒理性
暴露途径
吸入，吞食，皮肤和/或眼睛接触
inhalation, ingestion, skin and/or eye contact
来源:The National Institute for Occupational Safety and Health (NIOSH)
毒理性
症状
眼睛刺激，呼吸系统；中枢神经系统抑制
irritation eyes, respiratory system; central nervous system depression
来源:The National Institute for Occupational Safety and Health (NIOSH)
1,2-Dichloroethene appears to be absorbed quickly by the lungs. One study reported that approximately 75% of the inhaled chemical was absorbed through the lungs in humans.
Method for the Production of N-Substituted (3-Dihalomethyl-1-Methyl-Pyrazole-4-yl) Carboxamides
申请人：Zierke Thomas
公开号：US20100174094A1
公开（公告）日：2010-07-08
The present invention relates to a process for preparing N-substituted (3-dihalomethylpyrazol-4-yl)carboxamides of the formula (I)
in which R
1
is optionally substituted phenyl or C
3
-C
7
-cycloalkyl, R
1a
is hydrogen or fluorine, or R
1a
together with R
1
is optionally substituted C
3
-C
5
-alkanediyl or C
5
-C
7
-cycloalkanediyl, R
2
is C
1
-C
6
-alkyl, C
2
-C
6
-alkenyl, C
2
-C
6
-alkynyl or C
1
-C
4
-alkoxy-C
1
-C
2
-alkyl, X is F or Cl and n is 0, 1, 2 or 3; which comprises
A) providing a compound of the formula (II)
in which X is F or Cl, Y is Cl or Br and R
2
has one of the meanings given above and
B) reacting a compound of the formula (II) with carbon monoxide and a compound of the formula (III)
in which R
1
, R
1a
and n have one of the meanings given above; in the presence of a palladium catalyst;
to intermediates used for the preparation according to the process according to the invention, and also to processes for their preparation.
The preparation of 13-methylgon-4-enes and novel 13-polycarbonalkylgon-4-enes by a new total synthesis is described. 13-Alkylgon-4-enes having progestational, anabolic and androgenic activities are prepared by forming a tetracylic gonane structure unsaturated in the 1,3,5(10),9(11) and 14-positions, selectively reducing in the B- and C-rings, and converting the aromatic A-ring compounds so-produced to gon-4-enes by Birch reduction and hydrolysis.
Designing hybrid foldamers: the effect on the peptide conformational bias of β- versus α- and γ-linear residues in alternation with (1R,2S)-2-aminocyclobutane-1-carboxylic acid
作者：Sergio Celis、Esther Gorrea、Pau Nolis、Ona Illa、Rosa M. Ortuño
DOI：10.1039/c1ob06575k
日期：——
Several oligomers constructed with (1R,2S)-2-aminocyclobutane-1-carboxylic acid and glycine, β-alanine, and γ-amino butyric acid (GABA), respectively, joined in alternation have been synthesized and studied by means of NMR and CD experiments as well as with computational calculations. Results account for the spacer length effect on folding and show that conformational preference for these hybrid peptides can be tuned from β-sheet-like folding for those containing a C2 or C4 linear segment to a helical folding for those with a C3 spacer between cyclobutane residues. The introduction of cyclic spacers between these residues does not modify the extended ribbon-type structure previously manifested in poly(cis-cyclobutane) β-oligomers.
9-alpha-hydroxy steroids, process for their preparation, process for the
申请人：Gist-Brocades N.V.
公开号：US05352809A1
公开（公告）日：1994-10-04
New 9-alphahydroxy steroids are prepared by the introduction of substituents on the D-ring of 9-alpha-hydroxy-androst-4-ene-3,17-dione. The resulting compounds are useful intermediates in the synthesis of corticosteroids.
