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Sulfonates
In organosulfur chemistry, a sulfonate is a salt, anion or ester of a sulfonic acid. Its formula is , containing the functional group , where R is typically an organyl group, amino group or a halogen atom. Sulfonates are the conjugate bases of sulfonic acids. Sulfonates are generally stable in water, non-oxidizing, and colorless. Many useful compounds and even some biochemicals feature sulfonates. Sulfonate salts Anions with the general formula are called sulfonates. They are the conjugate bases of sulfonic acids with formula . As sulfonic acids tend to be strong acids, the corresponding sulfonates are weak bases. Due to the stability of sulfonate anions, the cations of sulfonate salts such as scandium triflate have application as Lewis acids. A classic preparation of sulfonates is the Strecker sulfite alkylation, in which an alkali sulfite salt displaces a halide, typically in the presence of an iodine catalyst: : An alternative is the condensation of a sulfonyl halid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfonate Anion Tet
In organosulfur chemistry, a sulfonate is a salt (chemistry), salt, anion or ester of a sulfonic acid. Its formula is , containing the functional group , where R is typically an organyl group, amino group or a halogen atom. Sulfonates are the conjugate bases of sulfonic acids. Sulfonates are generally stable in water, non-oxidizing, and colorless. Many useful compounds and even some biochemicals feature sulfonates. Sulfonate salts Anions with the general formula are called sulfonates. They are the conjugate bases of sulfonic acids with formula . As sulfonic acids tend to be strong acids, the corresponding sulfonates are weak base (chemistry), bases. Due to the stability of sulfonate anions, the cations of sulfonate salts such as scandium triflate have application as Lewis acids. A classic organic reaction, preparation of sulfonates is the Strecker sulfite alkylation, in which an alkali sulfite salt displaces a halide, typically in the presence of an iodine catalyst: : An al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfonic Acid
In organic chemistry, sulfonic acid (or sulphonic acid) refers to a member of the class of organosulfur compounds with the general formula , where R is an organic alkyl or aryl group and the group a sulfonyl hydroxide. As a substituent, it is known as a sulfo group. A sulfonic acid can be thought of as sulfuric acid with one hydroxyl group replaced by an organic substituent. The parent compound (with the organic substituent replaced by hydrogen) is the parent sulfonic acid, , a tautomer of sulfurous acid, . Salt (chemistry), Salts or esters of sulfonic acids are called sulfonates. Preparation Aryl sulfonic acids are produced by the process of sulfonation. Usually the sulfonating agent is sulfur trioxide. A large scale application of this method is the production of alkylbenzenesulfonic acids: : In this reaction, sulfur trioxide is an electrophile and the arene is the nucleophile. The reaction is an example of electrophilic aromatic substitution. In a related process, carboxyli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scandium Triflate
Scandium trifluoromethanesulfonate, commonly called scandium triflate, is a chemical compound with formula Sc(SO3CF3)3, a salt (chemistry), salt consisting of scandium cations Sc3+ and triflate anions. Scandium triflate is used as a reagent in organic chemistry as a Lewis acid. Compared to other Lewis acids, this reagent is stable towards water and can often be used in organic reactions as a true catalyst rather than one used in stoichiometric amounts. The compound is prepared by reaction of scandium oxide with trifluoromethanesulfonic acid. An example of the scientific use of scandium triflate is the Mukaiyama aldol addition reaction between benzaldehyde and the silyl enol ether of cyclohexanone with an 81% yield (chemistry), yield. : See also * Lanthanide trifluoromethanesulfonates References {{Scandium compounds Scandium compounds Triflates Acid catalysts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Triflate
Methyl trifluoromethanesulfonate, also commonly called methyl triflate and abbreviated MeOTf, is the organic compound with the formula . It is a colourless liquid which finds use in organic chemistry as a powerful methylating agent. The compound is closely related to methyl fluorosulfonate (). Although there has yet to be a reported human fatality, several cases were reported for methyl fluorosulfonate (LC50 (rat, 1 h) = 5 ppm), and methyl triflate is expected to have similar toxicity based on available evidence. Synthesis Methyl triflate is commercially available, however it may also be prepared in the laboratory by treating dimethyl sulfate with triflic acid. : Reactivity Hydrolysis Upon contact with water, methyl triflate loses its methyl group, forming triflic acid and methanol: : Methylation One ranking of methylating agents is . Methyl triflate will alkylate many functional groups which are very poor nucleophiles such as aldehydes, amides, and nitriles. It does not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leaving Group
In organic chemistry, a leaving group typically means a Chemical species, molecular fragment that departs with an electron, electron pair during a reaction step with heterolysis (chemistry), heterolytic bond cleavage. In this usage, a ''leaving group'' is a less formal but more commonly used synonym of the term ''nucleofuge''; although IUPAC gives the term a broader definition. A species' ability to serve as a leaving group can affect whether a reaction is viable, as well as what mechanism the reaction takes. Leaving group ability depends strongly on context, but often correlates with ability to stabilize additional electron density from bond heterolysis. Common anionic leaving groups are , and halides and sulfonate esters such as tosylate (). Water (), alcohols (), and amines () are common neutral leaving groups, although they often require activating catalysts. Some moieties, such as hydride (H−) serve as leaving groups only extremely rarely. Nomenclature IUPAC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Trifluoromethanesulfonate
Methyl trifluoromethanesulfonate, also commonly called methyl triflate and abbreviated MeOTf, is the organic compound with the formula . It is a colourless liquid which finds use in organic chemistry as a powerful methylating agent. The compound is closely related to methyl fluorosulfonate (). Although there has yet to be a reported human fatality, several cases were reported for methyl fluorosulfonate (LC50 (rat, 1 h) = 5 ppm), and methyl triflate is expected to have similar toxicity based on available evidence. Synthesis Methyl triflate is commercially available, however it may also be prepared in the laboratory by treating dimethyl sulfate with triflic acid. : Reactivity Hydrolysis Upon contact with water, methyl triflate loses its methyl group, forming triflic acid and methanol: : Methylation One ranking of methylating agents is . Methyl triflate will alkylate many functional groups which are very poor nucleophiles such as aldehydes, amides, and nitriles. It does not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl
In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula (whereas normal methane has the formula ). In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in many organic compounds. It is a very stable group in most molecules. While the methyl group is usually part of a larger molecule, bonded to the rest of the molecule by a single covalent bond (), it can be found on its own in any of three forms: methanide anion (), methylium cation () or methyl radical (). The anion has eight valence electrons, the radical seven and the cation six. All three forms are highly reactive and rarely observed. Methyl cation, anion, and radical Methyl cation The methylium cation () exists in the gas phase, but is otherwise not encountered. Some compounds are considered to be sources of the cation, and this simplification is used pervasively in organic chemistry. For exam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annalen Der Chemie Und Pharmacie
''Justus Liebig's Annalen der Chemie'' (often cited as ''Liebigs Annalen'') was one of the oldest and historically most important journals in the field of organic chemistry worldwide. It was established in 1832 and edited by Justus von Liebig with Friedrich Wöhler and others until Liebig's death in 1873. The journal was originally titled ''Annalen der Pharmacie''; its name was changed to ''Justus Liebig's Annalen der Chemie'' in 1874. In its first decades of publishing, the journal was both a periodical containing news of the chemical and pharmaceutical fields and a publisher of primary research. During this time, it was noted to contain rebuttals and criticism of the works it published, inserted by Justus von Liebig during his tenure as an editor. After 1874, changes were made to editorial policies, and the journal published only completed research; later on, in the 20th century, its focus was narrowed to only print articles on organic chemistry, though it had always placed em ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iodine
Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at , and boils to a violet gas at . The element was discovered by the French chemist Bernard Courtois in 1811 and was named two years later by Joseph Louis Gay-Lussac, after the Ancient Greek , meaning 'violet'. Iodine occurs in many oxidation states, including iodide (I−), iodate (), and the various periodate anions. As the heaviest essential mineral nutrient, iodine is required for the synthesis of thyroid hormones. Iodine deficiency affects about two billion people and is the leading preventable cause of intellectual disabilities. The dominant producers of iodine today are Chile and Japan. Due to its high atomic number and ease of attachment to organic compounds, it has also found favour as a non-toxic radiocontrast material. Because of the spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halide
In chemistry, a halide (rarely halogenide) is a binary chemical compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative (or more electropositive) than the halogen, to make a fluoride, chloride, bromide, iodide, astatide, or theoretically tennesside compound. The alkali metals combine directly with halogens under appropriate conditions forming halides of the general formula, MX (X = F, Cl, Br or I). Many salts are halides; the ''hal-'' syllable in ''halide'' and '' halite'' reflects this correlation. A halide ion is a halogen atom bearing a negative charge. The common halide anions are fluoride (), chloride (), bromide (), and iodide (). Such ions are present in many ionic halide salts. Halide minerals contain halides. All these halide anions are colorless. Halides also form covalent bonds, examples being colorless TiF4, colorless TiCl4, orange TiBr4, and brown TiI4. The heavier members TiCl4, TiBr4 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
