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Dibenzofurans
Dibenzofuran is a heterocyclic organic compound with the chemical structure shown at right. It is an aromatic compound that has two benzene rings fused to a central furan ring. All the numbered carbon atoms have a hydrogen atom bonded to each of them. It is a volatile white solid that is soluble in nonpolar organic solvents. It is obtained from coal tar, where it exists as a 1% component.Gerd Collin and Hartmut Höke "Benzofurans" in Ullmann's Encyclopedia of Industrial Chemistry, 2007, Wiley-VCH, Weinheim. Reactions Dibenzofuran is thermally robust with a convenient liquid range. These properties, together with its low toxicity, are exploited by the use of DBF as a heat transfer agent. It undergoes electrophilic reactions, such as halogenation and Friedel-Crafts reactions. Reaction of DBF with butyl lithium results in di lithiation.Ulrich Iserloh, Yoji Oderaotoshi, Shuji Kanemasa, and Dennis P. Curran "Synthesis of (R,R)-4,6-Dibenzofurandiyl-2,2'-Bis (4-Phenyloxazoline) (DBF ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polychlorinated Dibenzofurans
More thorough treatise of all groups with similar actions and binding to aryl hydrocarbon receptor is given in Dioxins and dioxin-like compounds. Polychlorinated dibenzofurans (PCDFs) are a family of organic compounds with one or several of the hydrogens in the dibenzofuran structure replaced by chlorines. For example, 2,3,7,8-tetrachlorodibenzofuran (TCDF) has chlorine atoms substituted for each of the hydrogens on the number 2, 3, 7, and 8 carbons (see structure in the upper left corner of the second image). Polychlorinated dibenzofurans with chlorines at least in positions 2,3,7 and 8 are much more toxic than the parent compound dibenzofurane, with properties and chemical structures similar to polychlorinated dibenzodioxins. These groups together are often inaccurately called dioxins. They are known developmental toxicants, and suspected human carcinogens. PCDFs tend to co-occur with polychlorinated dibenzodioxins (PCDDs). PCDFs can be formed by pyrolysis or incineration at te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dibenzofurans
Dibenzofuran is a heterocyclic organic compound with the chemical structure shown at right. It is an aromatic compound that has two benzene rings fused to a central furan ring. All the numbered carbon atoms have a hydrogen atom bonded to each of them. It is a volatile white solid that is soluble in nonpolar organic solvents. It is obtained from coal tar, where it exists as a 1% component.Gerd Collin and Hartmut Höke "Benzofurans" in Ullmann's Encyclopedia of Industrial Chemistry, 2007, Wiley-VCH, Weinheim. Reactions Dibenzofuran is thermally robust with a convenient liquid range. These properties, together with its low toxicity, are exploited by the use of DBF as a heat transfer agent. It undergoes electrophilic reactions, such as halogenation and Friedel-Crafts reactions. Reaction of DBF with butyl lithium results in di lithiation.Ulrich Iserloh, Yoji Oderaotoshi, Shuji Kanemasa, and Dennis P. Curran "Synthesis of (R,R)-4,6-Dibenzofurandiyl-2,2'-Bis (4-Phenyloxazoline) (DBF ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyozellin
Polyozellin is a chemical which occurs in the mushroom ''Polyozellus multiplex''. It inhibits prolyl endopeptidase, an enzyme that has a role in processing proteins (specifically, amyloid precursor protein) in Alzheimer's disease. Chemicals that inhibit prolyl endopeptidase have attracted research interest due to their potential therapeutic effects. Structurally related dibenzofuran Dibenzofuran is a heterocyclic organic compound with the chemical structure shown at right. It is an aromatic compound that has two benzene rings fused to a central furan ring. All the numbered carbon atoms have a hydrogen atom bonded to each of t ...yl derivatives of polyozellin are known as kynapcins. References Dibenzofurans Benzofuran ethers at the benzene ring Acetate esters Phenol esters Hydroxyquinol ethers {{Aromatic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, and highly combustible. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all normal matter.However, most of the universe's mass is not in the form of baryons or chemical elements. See dark matter and dark energy. Stars such as the Sun are mainly composed of hydrogen in the plasma state. Most of the hydrogen on Earth exists in molecular forms such as water and organic compounds. For the most common isotope of hydrogen (symbol 1H) each atom has one proton, one electron, and no neutrons. In the early universe, the formation of protons, the nuclei of hydrogen, occurred during the first second after the Big Bang. The emergence of neutral hydrogen atoms throughout the universe occur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agency For Toxic Substances And Disease Registry
The Agency for Toxic Substances and Disease Registry (ATSDR) is a federal public health agency within the United States Department of Health and Human Services. The agency focuses on minimizing human health risks associated with exposure to hazardous substances. It works closely with other federal, state, and local agencies; tribal governments; local communities; and healthcare providers. Its mission is to "Serve the public through responsive public health actions to promote healthy and safe environments and prevent harmful exposures." ATSDR was created as an advisory, nonregulatory agency by the Superfund legislation and was formally organized in 1985. Although ATSDR is an independent operating agency within the Department of Health and Human Services, the Centers for Disease Control and Prevention (CDC) performs many of its administrative functions. The CDC director also serves as the ATSDR administrator, and ATSDR has a joint Office of the Director with the National Center ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dioxins And Dioxin-like Compounds
Dioxins and dioxin-like compounds (DLCs) are a group of chemical compounds that are persistent organic pollutants (POPs) in the environment. They are mostly by-products of burning or various industrial processes - or, in case of dioxin-like PCBs and PBBs, unwanted minor components of intentionally produced mixtures. Some of them are highly toxic, but the toxicity among them varies 30,000-fold. They are grouped together because their mechanism of action is the same. They activate the aryl hydrocarbon receptor (AH receptor), albeit with very different binding affinities, leading to high differences in toxicity and other effects. They include: * Polychlorinated dibenzo''-p-''dioxins (PCDDs), or simply dioxins. PCDDs are derivatives of dibenzo''-p-''dioxin. There are 75 PCDD congeners, differing in the number and location of chlorine atoms, and 7 of them are specifically toxic, the most toxic being 2,3,7,8-tetrachlorodibenzodioxin (TCDD). * Polychlorinated dibenzofurans (PCDFs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Succinic Anhydride
Succinic anhydride, is an organic compound with the molecular formula (CH2CO)2O. This colorless solid is the acid anhydride of succinic acid. Preparation In the laboratory, this material can be prepared by dehydration of succinic acid. Such dehydration can occur with the help of acetyl chloride or phosphoryl chloride, or thermally. Industrially, succinic anhydride is prepared by catalytic hydrogenation of maleic anhydride. Reactions Succinic anhydride hydrolyzes readily to give succinic acid: :(CH2CO)2O + H2O → (CH2CO2H)2 With alcohols (ROH), a similar reaction occurs, delivering the monoester: :(CH2CO)2O + ROH → RO2CCH2CH2CO2H Succinic anhydride is used in acylations under Friedel-Crafts conditions, as illustrated by the industrial route to the drug Fenbufen. Related compounds Maleic anhydride undergoes the Alder-ene reaction with alkenes to give alkenylsuccinic anhydrides. Such compounds are sizing agents in the paper industry. In this role, the anhydride is prop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dennis Patrick Curran
Dennis P. Curran (born June 10, 1953) is an American organic chemist and a professor of chemistry at University of Pittsburgh known for his research in the fields of organic chemistry, radical chemistry, and fluorous chemistry. Career and personal life Curran received his BS degree from Boston College in 1975 and his PhD degree from the University of Rochester in 1979 working under the direction of Andrew S. Kende. After postdoctoral studies with Barry Trost at the University of Wisconsin, he joined the University of Pittsburgh Department of Chemistry as an Assistant Professor in 1981. He became Associate Professor in 1986, Full Professor in 1988, and Distinguished Service Professor in 1995. He became the first Bayer Professor of Chemistry in 1996 and since 2019 is the Covestro Professor of Chemistry. Chemistry runs in Curran's family. His father, Dr. William V. Curran (1929-2019), was a 60-year member of the American Chemical Society and the inventor of the third-generation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithiation
In organometallic chemistry, organolithium reagents are chemical compounds that contain carbon–lithium (C–Li) bonds. These reagents are important in organic synthesis, and are frequently used to transfer the organic group or the lithium atom to the substrates in synthetic steps, through nucleophilic addition or simple deprotonation. Organolithium reagents are used in industry as an initiator for anionic polymerization, which leads to the production of various elastomers. They have also been applied in asymmetric synthesis in the pharmaceutical industry. Due to the large difference in electronegativity between the carbon atom and the lithium atom, the C−Li bond is highly ionic. Owing to the polar nature of the C−Li bond, organolithium reagents are good nucleophiles and strong bases. For laboratory organic synthesis, many organolithium reagents are commercially available in solution form. These reagents are highly reactive, and are sometimes pyrophoric. History and dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coal Tar
Coal tar is a thick dark liquid which is a by-product of the production of coke and coal gas from coal. It is a type of creosote. It has both medical and industrial uses. Medicinally it is a topical medication applied to skin to treat psoriasis and seborrheic dermatitis (dandruff). It may be used in combination with ultraviolet light therapy. Industrially it is a railroad tie preservative and used in the surfacing of roads. Coal tar was listed as a known human carcinogen in the first Report on Carcinogens from the U.S. Federal Government. Coal tar was discovered circa 1665 and used for medical purposes as early as the 1800s. Circa 1850, the discovery that it could be used as the main ingredient in synthetic dyes engendered an entire industry. It is on the World Health Organization's List of Essential Medicines. Coal tar is available as a generic medication and over the counter. Side effects include skin irritation, sun sensitivity, allergic reactions, and skin discolorat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Furan
Furan is a heterocyclic organic compound, consisting of a five-membered aromatic ring with four carbon atoms and one oxygen atom. Chemical compounds containing such rings are also referred to as furans. Furan is a colorless, flammable, highly volatile liquid with a boiling point close to room temperature. It is soluble in common organic solvents, including alcohol, ether, and acetone, and is slightly soluble in water. Its odor is "strong, ethereal; chloroform-like". It is toxic and may be carcinogenic in humans. Furan is used as a starting point for other speciality chemicals. History The name "furan" comes from the Latin ''furfur'', which means bran. (Furfural is produced from bran.) The first furan derivative to be described was 2-furoic acid, by Carl Wilhelm Scheele in 1780. Another important derivative, furfural, was reported by Johann Wolfgang Döbereiner in 1831 and characterised nine years later by John Stenhouse. Furan itself was first prepared by Heinri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
