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Thiophenol
Thiophenol is an organosulfur compound with the formula C6H5SH, sometimes abbreviated as PhSH. This foul-smelling colorless liquid is the simplest aromatic thiol. The chemical structures of thiophenol and its derivatives are analogous to phenols, where the oxygen atom in the hydroxyl group (−OH) bonded to the aromatic ring in phenol is replaced by a sulfur atom. The prefix thio- implies a sulfur-containing compound and when used before a root word name for a compound which would normally contain an oxygen atom, in the case of 'thiol' that the alcohol oxygen atom is replaced by a sulfur atom. Thiophenols also describes a class of compounds formally derived from thiophenol itself. All have a sulfhydryl group (-SH) covalently bonded to an aromatic ring. The organosulfur ligand in the medicine thiomersal is a thiophenol. Synthesis There are several methods of synthesis for thiophenol and related compounds, although thiophenol itself is usually purchased for laboratory oper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfhydryl Group
In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl group, or a sulfanyl group. Thiols are the sulfur analogue of alcohols (that is, sulfur takes the place of oxygen in the hydroxyl () group of an alcohol), and the word is a blend of "''thio-''" with "alcohol". Many thiols have strong odors resembling that of garlic, cabbage or rotten eggs. Thiols are used as odorants to assist in the detection of natural gas (which in pure form is odorless), and the smell of natural gas is due to the smell of the thiol used as the odorant. Nomenclature Thiols are sometimes referred to as mercaptans () or mercapto compounds, a term introduced in 1832 by William Christopher Zeise and is derived from the Latin ('capturing mercury')''Oxford American Dictionaries'' (Mac OS X Leopard). because the thiolate group ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzeneselenol
Benzeneselenol, also known as selenophenol, is the organoselenium compound with the chemical formula , often abbreviated PhSeH. It is the selenium analog of phenol. This colourless, malodorous compound is a reagent in organic synthesis. Synthesis Benzeneselenol is prepared by the reaction of phenylmagnesium bromide and selenium: :PhMgBr + Se → PhSeMgBr :PhSeMgBr + HCl → PhSeH + MgBrCl Since benzeneselenol does not have a long shelf life, it is often generated in situ. A common method is by reduction of diphenyldiselenide. A further reason for this conversion is that often, it is the anion that is sought. Reactions More so than thiophenol, benzeneselenol is easily oxidized by air. The facility of this reaction reflects the weakness of the Se-H bond, bond dissociation energy of which is estimated to be between 67 and 74 kcal/mol. In contrast, the S-H BDE for thiophenol is near 80 kcal/mol. The product is diphenyl diselenide as shown in this idealized equation: : The presen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newman–Kwart Rearrangement
The Newman–Kwart rearrangement is a type of rearrangement reaction in which the aryl group of an ''O''-aryl thiocarbamate, ArOC(=S)NMe2, migrates from the oxygen atom to the sulfur atom, forming an ''S''-aryl thiocarbamate, ArSC(=O)NMe2. The reaction is named after its discoverers, Melvin Spencer Newman and Harold Kwart. The reaction is a manifestation of the double bond rule. The Newman–Kwart reaction represents a useful synthetic tool for the preparation of thiophenol derivatives. : Mechanism The Newman–Kwart rearrangement is intramolecular. It is generally believed to be a concerted process, proceeding ''via'' a four-membered cyclic transition state (rather than a two-step process passing through a discrete reactive intermediate). The enthalpy of activation for this transition state is generally quite high for typical substrates (Δ''H''‡ ~ 30 to 40 kcal/mol), necessitating high reaction temperatures (200 to 300 °C, Ph2O as solvent or heat). : A Pd-catalyzed pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leuckart Thiophenol Reaction
The Leuckart thiophenol reaction is the decomposition of a diazoxanthate, by gentle warming in a slightly acidic cuprous medium, to its corresponding aryl xanthates which give aryl thiols on alkaline hydrolysis and aryl thioethers on further warming. This reaction was first reported by Rudolf Leuckart Karl Georg Friedrich Rudolf Leuckart (7 October 1822 – 22 February 1898) was a German zoologist born in Helmstedt. He was a pioneer of parasitology research and was widely known for developing a series of illustrated wall charts for use in zo ... in 1890.Merck Index 14th Ed. References Organic reactions Name reactions Coupling reactions {{Reaction-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenol
Phenol (also known as carbolic acid, phenolic acid, or benzenol) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile and can catch fire. The molecule consists of a phenyl group () bonded to a hydroxy group (). Mildly acidic, it requires careful handling because it can cause chemical burns. It is acutely toxic and is considered a health hazard. Phenol was first extracted from coal tar, but today is produced on a large scale (about 7 million tonnes a year) from petroleum-derived feedstocks. It is an important industrial commodity as a precursor to many materials and useful compounds, and is a liquid when manufactured. It is primarily used to synthesize plastics and related materials. Phenol and its chemical derivatives are essential for production of polycarbonates, epoxies, explosives such as picric acid, Bakelite, nylon, detergents, herbicides such as phenoxy herbicides, and numerous pharmaceuti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diphenyl Disulfide
Diphenyl disulfide is the chemical compound with the formula (C6H5S)2. This colorless crystalline material is often abbreviated Ph2S2. It is one of the more commonly encountered organic disulfides in organic synthesis. Minor contamination by thiophenol is responsible for the disagreeable odour associated with this compound. Preparation and structure Diphenyl disulfide is usually prepared by the oxidation of thiophenol: : 2 PhSH + iodine, I2 → Ph2S2 + 2 HI Hydrogen peroxide can also be used as the oxidant. Ph2S2 is rarely prepared in the laboratory because it is inexpensive, and the precursor has a disagreeable odour. Like most organic disulfides, the C–S–S–C core of Ph2S2 is non-planar with a dihedral angle approaching 85°. Reactions Ph2S2 is mainly used in organic synthesis as a source of the PhS substituent. A typical reaction entails the formation of PhS-substituted carbonyl compounds via the enolate: :RC(O)CHLiR' + Ph2S2 → RC(O)CH(SPh)R' + LiSPh Reduction Ph2S2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grignard Reagent
Grignard reagents or Grignard compounds are chemical compounds with the general formula , where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride and phenylmagnesium bromide . They are a subclass of the organomagnesium compounds. Grignard compounds are popular reagents in organic synthesis for creating new carbon–carbon bonds. For example, when reacted with another halogenated compound in the presence of a suitable catalyst, they typically yield and the magnesium halide as a byproduct; and the latter is insoluble in the solvents normally used. Grignard reagents are rarely isolated as solids. Instead, they are normally handled as solutions in solvents such as diethyl ether or tetrahydrofuran using air-free techniques. Grignard reagents are complex with the magnesium atom bonded to two ether ligands as well as the halide and organyl ligands. The discovery of the Grignard reaction in 1900 was recogn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenyllithium
Phenyllithium is an organometallic agent with the empirical formula . It is most commonly used as a metalating agent in organic syntheses and a substitute for Grignard reagents for introducing phenyl groups in organic syntheses. Crystalline phenyllithium is colorless; however, solutions of phenyllithium are various shades of brown or red depending on the solvent used and the impurities present in the solute. Preparation Phenyllithium was first produced by the reaction of lithium metal with diphenylmercury: : Reaction of a phenyl halide with lithium metal produces phenyllithium: : Phenyllithium can also be synthesized with a metal-halogen exchange reaction: : The predominant method of producing phenyllithium today are the latter two syntheses. Reactions The primary use of PhLi is to facilitate formation of carbon-carbon bonds by nucleophilic addition and substitution reactions: : 2-Phenylpyridine is prepared by the reaction of phenyl lithium with pyridine, a process that entail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xanthate
A xanthate is a Salt (chemistry), salt or ester of a xanthic acid. The formula of the salt of xanthic acid is (where R is organyl group and M is usually Sodium, Na or Potassium, K). Xanthate also refers to the anion . The formula of a xanthic acid is , such as ethyl xanthic acid, while the formula of a xanthate ester is , where R and R' are organyl groups. The salts of xanthates are sometimes called ''O''-organyl dithioates. The esters of xanthic acid are sometimes called ''O'',''S''-diorganyl esters of Dithiocarbonate, dithiocarbonic acid. The name ''xanthate'' is derived from Ancient Greek (''xanthos'') meaning 'yellowish' or 'golden', and indeed most xanthate salts are yellow. They were discovered and named in 1823 by Danish chemist William Christopher Zeise. These organosulfur compounds are important in two areas: the production of cellophane and related polymers from cellulose and (in mining) for extraction of certain sulphide bearing ores. They are also versatile intermedi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aniline
Aniline (From , meaning ' indigo shrub', and ''-ine'' indicating a derived substance) is an organic compound with the formula . Consisting of a phenyl group () attached to an amino group (), aniline is the simplest aromatic amine. It is an industrially significant commodity chemical, as well as a versatile starting material for fine chemical synthesis. Its main use is in the manufacture of precursors to polyurethane, dyes, and other industrial chemicals. Like most volatile amines, it has the odor of rotten fish. It ignites readily, burning with a smoky flame characteristic of aromatic compounds. It is toxic to humans. Relative to benzene, aniline is "electron-rich". It thus participates more rapidly in electrophilic aromatic substitution reactions. Likewise, it is also prone to oxidation: while freshly purified aniline is an almost colorless oil, exposure to air results in gradual darkening to yellow or red, due to the formation of strongly colored, oxidized impurities. Ani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
