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Organic Thiocyanates
Organic thiocyanates are organic compounds containing the functional group RSCN. the organic group is attached to sulfur: R−S−C≡N has a S–C single bond and a C≡N triple bond. Organic thiocyanates are valued building blocks. They allow to access efficiently various sulfur containing functional groups and scaffolds. Synthesis Several synthesis routes exist, the most common being the reaction between alkyl halides and alkali thiocyanate in aqueous media. Illustrative is the preparation of isopropyl thiocyanate by treatment of isopropyl bromide with sodium thiocyanate in boiling ethanol. The main complication with this route is the competing formation of alkyisothiocyanates. "SN1-type" substrates (e.g., benzyl halides) tend to give the isothiocyanate derivatives. Some organic thiocyanates are generated by cyanation of some organosulfur compounds. Sulfenyl thiosulfates (RSSO3−) react with alkali metal cyanides to give thiocyanates with displacement of sulfite. This ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Picometer
The picometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: pm) or picometer ( American spelling) is a unit of length in the International System of Units (SI), equal to , or one trillionth of a metre, which is the SI base unit of length. The picometre is one thousand femtometres, one thousandth of a nanometre ( nm), one millionth of a micrometre (also known as a micron), one billionth of a millimetre, and one trillionth of a metre. The symbol μμ was once used for it. It is also one hundredth of an ångström, an internationally known (but non-SI) unit of length. Use The picometre's length is of an order so small that its application is almost entirely confined to particle physics, quantum physics, chemistry and acoustics. Atoms are between 62 and 520 pm in diameter, and the typical length of a carbon–carbon single bond is 154 pm. Smaller units still may be used to describe smaller particles (some of whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Thiocyanate
Methyl thiocyanate is an organic compound with the formula CH3SCN. The simplest member of the organic thiocyanates, it is a colourless liquid with an onion-like odor. It is produced by the methylation of thiocyanate salts. The compound is a precursor to the more useful isomer methyl isothiocyanate (CH3NCS).F. Romanowski, H. Klenk "Thiocyanates and Isothiocyanates, Organic" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH: Weinheim. Safety The LD50 is 60 mg/kg (rats, oral). It is listed as an extremely hazardous substance by the United States's Emergency Planning and Community Right-to-Know Act The Emergency Planning and Community Right-to-Know Act of 1986 is a United States federal law passed by the 99th United States Congress located at Title 42, Chapter 116 of the U.S. Code, concerned with emergency response preparedness. On October .... References {{sulfur compounds Thiocyanates Methyl esters Foul-smelling chemicals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isothiocyanate
In organic chemistry, isothiocyanate is the functional group , formed by substituting the oxygen in the isocyanate group with a sulfur. Many natural isothiocyanates from plants are produced by enzymatic conversion of metabolites called glucosinolates. These natural isothiocyanates, such as allyl isothiocyanate, are also known as mustard oils. An artificial isothiocyanate, phenyl isothiocyanate, is used for amino acid sequencing in the Edman degradation. Cruciferous vegetables, such as bok choy, broccoli, cabbage, cauliflower, kale, and others, are rich sources of glucosinolate precursors of isothiocyanates. Although there has been some basic research on how isothiocyanates might exert biological effects ''in vivo'', there is no high-quality evidence to date for its efficacy against human diseases. Structure Typical bond angles for and linkages in aryl isothiocyanates are 165° and 177°, respectively. The and distances are 117 and 158 pms. Synthesis and reactions Is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allyl Isothiocyanate
Allyl isothiocyanate (AITC) is an organosulfur compound (formula CH2CHCH2NCS). This colorless oil is responsible for the pungent taste of mustard, radish, horseradish, and wasabi. This pungency and the lachrymatory effect of AITC are mediated through the TRPA1 and TRPV1 ion channels. It is slightly soluble in water, but more soluble in most organic solvents. Biosynthesis and biological functions Allyl isothiocyanate can be obtained from the seeds of black mustard (''Brassica nigra'') or brown Indian mustard (''Brassica juncea''). When these mustard seeds are broken, the enzyme myrosinase is released and acts on a glucosinolate known as sinigrin to give allyl isothiocyanate. Allyl isothiocyanate serves the plant as a defense against herbivores; since it is harmful to the plant itself , it is stored in the harmless form of the glucosinolate, separate from the myrosinase enzyme. When an animal chews the plant, the allyl isothiocyanate is released, repelling the animal. Human ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Riemschneider Thiocarbamate Synthesis
The Riemschneider thiocarbamate synthesis converts alkyl or aryl thiocyanates to thiocarbamates under acidic conditions, followed by hydrolysis with ice water. The reaction was discovered by the German chemist in 1951 as a more efficient method to produce thiocarbamates. Some references spell the name ''Riemenschneider''. 500px, center The Riemschneider reaction can also be used to create the corresponding ''N''-substituted thiocarbamate from an alcohol or alkene. Mechanism The mechanism for the conversion of an alcohol to the N-substituted thiocarbamate is shown below. The reaction proceeds under acidic conditions. The alcohol accepts a hydrogen ion from sulfuric acid to form a water, which then leaves, creating a carbocation A carbocation is an ion with a positively charged carbon atom. Among the simplest examples are the methenium , methanium and vinyl cations. Occasionally, carbocations that bear more than one positively charged carbon atom are also encoun .... ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiocarbamate
In organic chemistry, thiocarbamates (thiourethanes) are a family of organosulfur compounds. As the prefix ''thio-'' suggests, they are sulfur analogues of carbamates. There are two isomeric forms of thiocarbamates: ''O''-thiocarbamates, (esters), and ''S''-thiocarbamates, (thioesters). Synthesis Thiocarbamates can be synthesised by the reaction of water or alcohols upon thiocyanates ( Riemschneider thiocarbamate synthesis): :RSCN + H2O → RSC(=O)NH2 :RSCN + R'OH → RSC(=O)NR'H Similar reactions are seen between alcohols and thiocarbamoyl chlorides such as dimethylthiocarbamoyl chloride; as well as between thiols and cyanates. Alternatively, they arise by the reaction of amines with carbonyl sulfide. :2 R2NH + COS → 2NH2+R2NCOS−] Reactions In the Newman-Kwart rearrangement ''O''-thiocarbamates can isomerise to ''S''-thiocarbamates. This reaction, which generally requires high temperatures, is an important method for the synthesis of thiophenols. Dithiocarbama ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bond Angle
Bond or bonds may refer to: Common meanings * Bond (finance), a type of debt security * Bail bond, a commercial third-party guarantor of surety bonds in the United States * Chemical bond, the attraction of atoms, ions or molecules to form chemical compounds People * Bond (surname) * Bonds (surname) * Mr. Bond (musician), Austrian rapper Arts and entertainment * James Bond, a series of works about the eponymous fictional character * James Bond (literary character), a British secret agent in a series of novels and films * Bond (band), an Australian/British string quartet ** '' Bond: Video Clip Collection'', a video collection from the band * Bond (Canadian band), a Canadian rock band in the 1970s * ''The Bond'' (2007 book), an American autobiography written by The Three Doctors * '' The Bond'', a 1918 film by Charlie Chaplin supporting Liberty bonds * Bond International Casino, a former music venue in New York City Places Antarctica * Bond Glacier, at the head of Vince ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isothiocyanate
In organic chemistry, isothiocyanate is the functional group , formed by substituting the oxygen in the isocyanate group with a sulfur. Many natural isothiocyanates from plants are produced by enzymatic conversion of metabolites called glucosinolates. These natural isothiocyanates, such as allyl isothiocyanate, are also known as mustard oils. An artificial isothiocyanate, phenyl isothiocyanate, is used for amino acid sequencing in the Edman degradation. Cruciferous vegetables, such as bok choy, broccoli, cabbage, cauliflower, kale, and others, are rich sources of glucosinolate precursors of isothiocyanates. Although there has been some basic research on how isothiocyanates might exert biological effects ''in vivo'', there is no high-quality evidence to date for its efficacy against human diseases. Structure Typical bond angles for and linkages in aryl isothiocyanates are 165° and 177°, respectively. The and distances are 117 and 158 pms. Synthesis and reactions Is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Thiocyanate
Methyl thiocyanate is an organic compound with the formula CH3SCN. The simplest member of the organic thiocyanates, it is a colourless liquid with an onion-like odor. It is produced by the methylation of thiocyanate salts. The compound is a precursor to the more useful isomer methyl isothiocyanate (CH3NCS).F. Romanowski, H. Klenk "Thiocyanates and Isothiocyanates, Organic" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH: Weinheim. Safety The LD50 is 60 mg/kg (rats, oral). It is listed as an extremely hazardous substance by the United States's Emergency Planning and Community Right-to-Know Act The Emergency Planning and Community Right-to-Know Act of 1986 is a United States federal law passed by the 99th United States Congress located at Title 42, Chapter 116 of the U.S. Code, concerned with emergency response preparedness. On October .... References {{sulfur compounds Thiocyanates Methyl esters Foul-smelling chemicals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon- hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The study of the properties, reactions, and syntheses of organic compounds comprise the discipline known as organic chemistry. For historical reasons, a few classes of carbon-containing compounds (e.g., carbonate salts and cyanide salts), along with a few other exceptions (e.g., carbon dioxide, hydrogen cyanide), are not classified as organic compounds and are considered inorganic. Other than those just named, little consensus exists among chemists on precisely which carbon-containing compounds are excluded, making any rigorous definition of an organic compound elusive. Although organic compounds make up only a small percentage of Earth's crust, they are of central importance because all known life is based on organic compounds. Livin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiocyanogen
Thiocyanogen, (SCN)2, is a pseudohalogen derived from the pseudohalide thiocyanate, CNsup>−. This hexatomic compound exhibits C2 point group symmetry and has the connectivity NCS-SCN. The oxidation ability is greater than bromine. It reacts with water: :3(SCN)2 + 4H2O → H2SO4 + HCN + 5SCN− + 5H+ Thiocyanogen was originally prepared by the reaction of iodine with a suspension of silver thiocyanate in diethyl ether, but this reaction suffers from competing equilibria attributed to the weak oxidizing power of iodine. These same investigations led Söderbäck to the isolation of sulfur dicyanide. An improved method for generating thiocyanogen entails oxidation of plumbous thiocyanate, which precipitates when aqueous solutions of lead(II) nitrate and sodium thiocyanate are combined. A suspension of anhydrous Pb(SCN)2 is treated with bromine in glacial acetic acid to afford a 0.1M solution of thiocyanogen that is stable for days. Alternatively, a solution of bromine i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
