Naphthalene appears as a white crystalline volatile solid with a strong coal-tar odor. The solid is denser than water and insoluble in water. Burns, but may be difficult to ignite. . In the molten form it is very hot. Exposure to skin must be avoided. Also the vapors given off by the material may be toxic. Used as a moth repellent, fumigant, lubricants, and to make other chemicals, and for many other uses
/It was shown/ that 24-35% of an intraperitoneal dose of (14)C-naphthalene was eliminated as mercapturates by both mice and rats at 24 hours after dosing. For both species, this percentage was the same over a wide dose range (3.12-200 mg/kg body weight). In contrast, after inhalation exposure, the amounts of mercapturic acid in mouse urine were approximately twice those in rat urine at the same level of exposure. Over a 24 hour period, approximately 100-500 umol/kg body weight mercapturates were eliminated in urine of mice given intraperitoneal injections of 50-200 mg/kg body weight naphthalene. In mice exposed by inhalation to 1-100 ppm (5.24-524 mg/cu m) naphthalene for 4 hours, 1-240 umol/kg body weight total mercapturic acids were eliminated, while rats exposed to the same concentrations eliminated 0.6-67 umol/kg body weight.
A 5 day old calf dosed orally with (14)C-propachlor excreted 70% dose in the urine as the cysteine conjugate; no mercapturic acid was detected. Rumen microflora were established in the calf (5 weeks older) and the experiment was repeated with the same results. When the same calf was dosed 1 week later with (14)C-naphthalene, 99% dose was excreted in the urine, mostly as the dihydrodiol glucuronide (34%) and the dihydrohydroxy cysteine conjugate (47%); no mercapturate was detected. ... Cysteine S-conjugate N-acetyltransferase activity in calf kidney and liver was about 10% of that n the corresponding rat tissues.
...Metabolized via 1,2-epoxide into 1,2-dihydronaphthalene-1,2-diol, 1,2-dihydro-1-naphthol and N-acetyl-s-(2-hydroxy-1,2-dihydronaphthyl)-cysteine, which after further metabolism... Excreted in urine as 1-naphthylmercapturic acid ...and conjugates of 1,2-dihydronaphthalene-1,2-diol... 1- and 2-naphthols, and 1,2-dihydroxynaphthalene.
Naphthalene is metabolized first to naphthalene 1,2-oxide, which can yield 1-naphthol or be converted by epoxide hydrolase to trans-1,2-dihydro- 1,2-dihydroxynaphthalene (trans-1,2-dihydrodiol . The hydroxyl group of 1-naphthol may also be sulfated or glucuronidated. The 1,2-dihydrodiol can also be converted to 2-naphthol. The epoxide is also a substrate for glutathione S-transferase, yielding glutathione conjugates which are eventually eliminated as mercapturic acids.
来源:Hazardous Substances Data Bank (HSDB)
代谢
萘已知的人类代谢物包括1-萘酚、2-萘酚、萘-1,2-环氧化和二氢二醇。
Naphthalene has known human metabolites that include 1-Naphthol, 2-Naphthol, naphthalene-1,2 Expodation, and dihydrodiol.
PAH's such as naphthalene are transported throughout the body after binding blood proteins such as albumin. Binding to the aryl hydrocarbon receptor or glycine N-methyltransferase induces the expression of cytochrome P450 enzymes (especially CYP1A1, CYP1A2, and CYP1B1). These cytochrome enzymes metabolize PAH's into various toxic intermediates (epoxide intermediates, dihydrodiols, phenols, quinones, and their various combinations). The reactive metabolites of PAHs covalently bind to DNA and other cellular macromolecules, initiating mutagenesis and carcinogenesis. (10, 12, 2, 3). In humans, the metabolite alpha-naphthol has been linked to the development of hemolytic anemia in some cases following ingestion or extensive dermal or inhalation exposure. Susceptibility appears to be exacerbated by a deficiency in the glucose 6-phosphate dehydrogenase enzyme, or G-6-PD. Over 400 million people have an inherited condition called glucose-6-phosphate dehydrogenase deficiency. Exposure to naphthalene is more harmful for these people and may cause hemolytic anemia at lower doses. Some naphthalene metabolites deplete glutathione stores in affected tissues such as the lungs, leading to toxicity. The metabolites responsible for glutathione depletion have been identified as naphthalene oxide or 1,2-naphthoquinone and 1,4-naphthoquinone.
WEIGHT-OF-EVIDENCE CHARACTERIZATION: Using criteria of the 1986 Guidelines for Carcinogen Risk Assessment, naphthalene is classified in group C, a possible human carcinogen. This is based on the inadequate data of carcinogenicity in humans exposed to naphthalene via the oral and inhalation routes, and the limited evidence of carcinogenicity in animals via the inhalation route. Using the 1996 Proposed Guidelines for Carcinogen Risk Assessment, the human carcinogenic potential of naphthalene via the oral or inhalation routes "cannot be determined" at this time based on human and animal data; however, there is suggestive evidence (observations of benign respiratory tumors and one carcinoma in female mice only exposed to naphthalene by inhalation). Additional support includes increase in respiratory tumors associated with exposure to 1-methylnaphthalene. At the present time the mechanism whereby naphthalene produces benign respiratory tract tumors are not fully understood, but are hypothesized to involve oxygenated reactive metabolites produced via the cytochrome P-450 monooxygenase system. However, based on the many negative results obtained in genotoxicity tests, a genotoxic mechanism appears unlikely. HUMAN CARCINOGENICITY DATA: Available data are inadequate to establish a causal association between exposure to naphthalene and cancer in humans. Adequately scaled epidemiological studies designed to examine a possible association between naphthalene exposure and cancer were not located. Overall, no data are available to evaluate the carcinogenic potential in exposed human populations.
来源:Hazardous Substances Data Bank (HSDB)
毒理性
致癌性证据
A3:已确认的动物致癌物,对人类的相关性未知。
A3: Confirmed animal carcinogen with unknown relevance to humans.
Evaluation: There is inadequate evidence in humans for the carcinogenicity of naphthalene. There is sufficient evidence in experimental animals for the carcinogenicity of naphthalene. Overall evaluation: Naphthalene is possibly carcinogenic to humans (Group 2B).
来源:Hazardous Substances Data Bank (HSDB)
毒理性
致癌性证据
萘基于在实验动物研究中的充分证据,合理预期对人是一种致癌物。
Naphthalene is reasonably anticipated to be a human carcinogen based on sufficient evidence from studies in experimental animals.
来源:Hazardous Substances Data Bank (HSDB)
吸收、分配和排泄
婴儿皮肤对萘的吸收会因婴儿油而增加。
Cutaneous absorption of naphthalene in infants is increased by baby oil.
来源:Hazardous Substances Data Bank (HSDB)
吸收、分配和排泄
吸入时,萘迅速被吸收……
When inhaled, naphthalene is rapidly absorbed... .
At 100 mg/kg intraperitoneally, 20 to 30% was excreted in the rat urine, and 85 to 90% /of urinary excretion/ was in the form of acid conjugates; 5 to 10% was excreted in the bile and 70 to 80% /of biliary excretion/ was as acid conjugates. The major metabolite was naphthalene-1,2-dihydrodiol.
In small oysters transport of naphthalene between tissues is primarily by diffusion. In intact oysters, accumulation in adductor muscle and body followed accumulation in gills after a large lag-time. In isolated tissues with no shell to impede water, there was no time lag.
A Method for the Net Contra-thermodynamic Isomerization of Cyclic Trisubstituted Alkenes
作者:Raphaël F. Guignard、Laurent Petit、Samir Z. Zard
DOI:10.1021/ol4018744
日期:2013.8.16
A simple sequence for the net contra-thermodynamic isomerization of cyclic trisubstituted alkenes is reported consisting of a radical addition of p-chlorothiophenol, followed by oxidation to the sulfoxide and thermal syn-elimination to give the least substituted isomeric cycloalkene.
The nickel-catalyzed reductive cleavage of esters in the absence of an external reductant, which involves the cleavage of an inert acyl C–O bond in O-alkyl esters is reported.
Copper-Catalyzed Protodecarboxylation of Aromatic Carboxylic Acids
作者:Lukas J. Gooßen、Werner R. Thiel、Nuria Rodríguez、Christophe Linder、Bettina Melzer
DOI:10.1002/adsc.200700223
日期:2007.10.8
A catalyst generated from copper(I) oxide and 4,7-diphenyl-1,10-phenanthroline for the first time allows the catalytic protodecarboxylation even of deactivated aromatic carboxylic acids, giving rise to the corresponding arenes. Based on DFT calculations, a reaction pathway is proposed that accurately reflects the experimental results, such as the observed reactivity order of the substrates.
Hydrazines and Azides via the Metal-Catalyzed Hydrohydrazination and Hydroazidation of Olefins
作者:Jérôme Waser、Boris Gaspar、Hisanori Nambu、Erick M. Carreira
DOI:10.1021/ja062355+
日期:2006.9.1
which the H and the N atoms come from two different reagents, a silane and an oxidizing nitrogen source (azodicarboxylate or sulfonyl azide). The hydrohydrazination reaction using di-tert-butyl azodicarboxylate is characterized by its ease of use, large functional group tolerance, and broad scope, including mono-, di-, tri-, and tetrasubstituted olefins. Key to the development of the hydroazidation
报道了 Co 和 Mn 催化的烯烃加氢肼和加氢叠氮化反应的发现、研究和实施。这些反应等效于 CC 双键与受保护的肼或偶氮酸的直接加氢胺化,但基于不同的概念,其中 H 和 N 原子来自两种不同的试剂,硅烷和氧化性氮源(偶氮二羧酸或磺酰叠氮化物) )。使用偶氮二羧酸二叔丁酯的加氢肼反应具有使用方便、官能团耐受性大、适用范围广的特点,包括单、二、三和四取代烯烃。氢叠氮化反应发展的关键是使用磺酰叠氮化物作为氮源和叔丁基过氧化氢的活化作用。发现该反应对于单、二和三取代烯烃的官能化是有效的,并且只有少数官能团是不能容忍的。获得的烷基叠氮化物是通用中间体,可以在不分离叠氮化物的情况下转化为游离胺或三唑。初步的机理研究表明,烯烃的氢化钴是限速的,然后是胺化反应。不能排除并可能涉及自由基中间体。然后进行胺化反应。不能排除并可能涉及自由基中间体。然后进行胺化反应。不能排除并可能涉及自由基中间体。
Regiospecific Cleavage of S–N Bonds in Sulfonyl Azides: Sulfonyl Donors
Sulfonyl azides have been widely used as sulfonamido, diazo, and azido donors, as well as all-nitrogen 1,3-dipoles donors in synthetic chemistry. Here, the sulfonyl azides were used as efficient sulfonyl donors, which is very unusual. Trifluoromethanesulfonic acid-induced formation of the sulfonyl cation reactive species from sulfonyl azides was developed and used for the first time to couple various