|
Methylenecyclopropane
Methylenecyclopropane is an organic compound with the formula (CH2)2CCH2. It is a colourless easily condensed gas that is used as a reagent in organic synthesis. Synthesis Methylenecyclopropane can be synthesised via an intramolecular cyclisation reaction from methallyl chloride by treatment with a strong base such as sodium amide. : Reactions Being a strained and unsaturated molecule methylenecyclopropane undergoes many reactions, especially in the presence of metal catalysts. For example, methylenecyclopropanes can be converted to cyclobutenes in the presence of a Platinum catalyst.''PtCl2-Catalyzed Rearrangement of Methylenecyclopropanes'' Alois Fürstner and Christophe Aïssa J. Am. Chem. Soc.; 2006; 128(19) pp 6306 -6307Abstract/ref> This can be considered similar to the ring expansion seen in vinylcyclopropane rearrangements : Substituted methylenecyclopropanes can also be involved in trimethylenemethane cycloaddition reactions. See also * Methylenecyclopropene * 1- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Amide
Sodium amide, commonly called sodamide (systematic name sodium azanide), is the inorganic compound with the formula . It is a salt composed of the sodium cation and the azanide anion. This solid, which is dangerously reactive toward water, is white, but commercial samples are typically gray due to the presence of small quantities of metallic iron from the manufacturing process. Such impurities do not usually affect the utility of the reagent. conducts electricity in the fused state, its conductance being similar to that of NaOH in a similar state. has been widely employed as a strong base in organic synthesis. Preparation and structure Sodium amide can be prepared by the reaction of sodium with ammonia gas, but it is usually prepared by the reaction in liquid ammonia using iron(III) nitrate as a catalyst. The reaction is fastest at the boiling point of the ammonia, c. −33 °C. An electride, , is formed as a reaction intermediate. : is a salt-like material and as such, c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylenecyclopropane Prepn
Methylenecyclopropane is an organic compound with the formula (CH2)2CCH2. It is a colourless easily condensed gas that is used as a reagent in organic synthesis. Synthesis Methylenecyclopropane can be synthesised via an intramolecular cyclisation reaction from methallyl chloride by treatment with a strong base such as sodium amide. : Reactions Being a strained and unsaturated molecule methylenecyclopropane undergoes many reactions, especially in the presence of metal catalysts. For example, methylenecyclopropanes can be converted to cyclobutenes in the presence of a Platinum catalyst.''PtCl2-Catalyzed Rearrangement of Methylenecyclopropanes'' Alois Fürstner and Christophe Aïssa J. Am. Chem. Soc.; 2006; 128(19) pp 6306 -6307Abstract/ref> This can be considered similar to the ring expansion seen in vinylcyclopropane rearrangements : Substituted methylenecyclopropanes can also be involved in trimethylenemethane cycloaddition reactions. See also * Methylenecyclopropene * 1- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trimethylenemethane Cycloaddition
Trimethylenemethane cycloaddition is the formal +2annulation of trimethylenemethane (TMM) derivatives to two-atom pi systems. Although TMM itself is too reactive and unstable to be stored, reagents which can generate TMM or TMM synthons ''in situ'' can be used to effect cycloaddition reactions with appropriate electron acceptors. Generally, electron-deficient pi bonds undergo cyclization with TMMs more easily than electron-rich pi bonds. Introduction Trimethylenemethane is a neutral, four-carbon molecule composed of four pi bonds; thus, it must be expressed either as a non-Kekulé molecule or a zwitterion. The orbital energy levels of TMM reveal that it possesses singlet and triplet states; generally, these states exhibit different reactivity and selectivity profiles. A singlet +2cycloaddition, when it is concerted, is believed to proceed under frontier orbital control. When electron-rich TMMs are involved, the ''A'' orbital serves as the HOMO (leading to fused products if the TM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylcyclopropane
Methylcyclopropane is an organic compound with the structural formula C3H5CH3. This colorless gas is the monomethyl derivative of cyclopropane Cyclopropane is the cycloalkane with the molecular formula (CH2)3, consisting of three methylene groups (CH2) linked to each other to form a ring. The small size of the ring creates substantial ring strain in the structure. Cyclopropane itself .... Reactions Methylcyclopropane, like many other cyclopropanes, undergoes ring-opening reactions. Bond cleavage in certain reactions is also reported in conjunction with the use of methylenecyclopropane groups as protective groups for amines. References {{Hydrocarbons Cyclopropyl compounds Hydrocarbons ... [...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. Living t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reagent
In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a substance ''consumed'' in the course of a chemical reaction. ''Solvents'', though involved in the reaction mechanism, are usually not called reactants. Similarly, ''catalysts'' are not consumed by the reaction, so they are not reactants. In biochemistry, especially in connection with enzyme-catalyzed reactions, the reactants are commonly called substrates. Definitions Organic chemistry In organic chemistry, the term "reagent" denotes a chemical ingredient (a compound or mixture, typically of inorganic or small organic molecules) introduced to cause the desired transformation of an organic substance. Examples include the Collins reagent, Fenton's reagent, and Grignard reagents. Analytical chemistry In analytical chemistry, a reagent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one of the most important branches of organic chemistry. There are several main areas of research within the general area of organic synthesis: ''total synthesis'', ''semisynthesis'', and ''methodology''. Total synthesis A total synthesis is the complete chemical synthesis of complex organic molecules from simple, commercially available petrochemical or natural precursors. Total synthesis may be accomplished either via a linear or convergent approach. In a ''linear'' synthesis—often adequate for simple structures—several steps are performed one after another until the molecule is complete; the chemical compounds made in each step are called synthetic intermediates. Most often, each step in a synthesis refers to a separate rea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methallyl Chloride
Methallyl chloride is the organic compound with the formula CH2=C(CH3)CH2Cl. It is a colorless liquid and a lacrymator. Its properties are similar to those of allyl chloride. It is a strong alkylating agent used to install isobutenyl groups. Reactivity It is also a precursor to meth allyl ligand. It is an isomer of crotyl chloride. Methylenecyclopropane can be synthesised via an intramolecular cyclisation reaction from methallyl chloride by treatment with a strong base such as sodium amide Sodium amide, commonly called sodamide (systematic name sodium azanide), is the inorganic compound with the formula . It is a salt composed of the sodium cation and the azanide anion. This solid, which is dangerously reactive toward water, is white .... : References {{Reflist Organochlorides IARC Group 3 carcinogens Allyl compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclobutene
Cyclobutene is a cycloalkene. It is of interest in research but currently has no practical applications. It is a colorless easily condensed gas. A modern synthesis involves the 2-step dehydration of cyclobutanol. The compound was first prepared by thermolysis of the ammonium salt 4H7NMe3H. Cyclobutene thermally isomerizes to 1,3-butadiene. This strongly exothermic reaction reflects the dominance of ring strain. In contrast, the corresponding equilibrium for hexafluorocyclobutene disfavors hexafluorobutadiene. See also * Cyclobutane * Cyclobutadiene * Cyclobutyne * Squaric acid Squaric acid, also called quadratic acid because its four carbon atoms approximately form a square, is a diprotic organic acid with the chemical formula C4O2(OH)2. The conjugate base of squaric acid is the hydrogensquarate anion ; and the conjug ... References Monomers {{hydrocarbon-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vinylcyclopropane Rearrangement
The vinylcyclopropane rearrangement or vinylcyclopropane-cyclopentene rearrangement is a ring expansion reaction, converting a vinyl-substituted cyclopropane ring into a cyclopentene ring. Intense experimental as well as computational investigations have revealed that mechanistically, the vinylcyclopropane rearrangement can be thought of as either a diradical-mediated two-step and/or orbital-symmetry-controlled pericyclic process. The amount by which each of the two mechanisms is operative is highly dependent on the substrate. Due to its ability to form cyclopentene rings the vinylcyclopropane rearrangement has served several times as a key reaction in complex natural product synthesis. Origins and history In 1959, a young research chemist with Humble Oil and Refining (Esso, now Exxon) named Norman P. Neureiter was instructed to find new uses for the excess butadiene produced from one of the refinery processes. Discussions about carbene chemistry with one of the company's most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylenecyclopropene
3-Methylenecyclopropene, also called methylenecyclopropene or triafulvene, is a hydrocarbon with chemical formula . It is a colourless gas that polymerizes readily as a liquid or in solution but is stable as a gas.W. E. Billups , Long Jin Lin , Edward W. Casserly "Synthesis of Methylenecyclopropene" J. Am. Chem. Soc., 1984, volume 106, pp 3698–3699. This highly strained and reactive molecule was synthesized and characterized for the first time in 1984, and has been the subject of considerable experimental and theoretical interest. It is an example of a cross-conjugated alkene, being composed of cyclopropene with an exocyclic double bond attached. Description Methylenecyclopropene is the smallest of the fulvenes (a family of unstable, cyclic molecules, conjugated transversally with an odd number of carbon atoms in the ring). The structure of methylenecyclopropene has two interacting double bonds, which represents the simplest transversally conjugated π-bonding system. It i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
