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Cyclopropane
Cyclopropane is the cycloalkane with the molecular formula (CH2)3, consisting of three methylene groups (CH2) linked to each other to form a triangular ring. The small size of the ring creates substantial ring strain in the structure. Cyclopropane itself is mainly of theoretical interest but many of its derivatives - cyclopropanes - are of commercial or biological significance. Cyclopropane was used as a clinical inhalational anesthetic from the 1930s through the 1980s. The substance's high flammability poses a risk of fire and explosions in operating rooms due to its tendency to accumulate in confined spaces, as its density is higher than that of air. History Cyclopropane was discovered in 1881 by August Freund, who also proposed the correct structure for the substance in his first paper. Freund treated 1,3-Dibromopropane, 1,3-dibromopropane with sodium, causing an intramolecular Wurtz reaction leading directly to cyclopropane. The yield of the reaction was improved by Gustavson ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ring Strain
In organic chemistry, ring strain is a type of instability that exists when bonds in a molecule form angles that are abnormal. Strain is most commonly discussed for small rings such as cyclopropanes and cyclobutanes, whose internal angles are substantially smaller than the idealized value of approximately 109°. Because of their high strain, the heat of combustion for these small rings is elevated. Ring strain results from a combination of angle strain, conformational strain or Pitzer strain (torsional eclipsing interactions), and transannular strain, also known as van der Waals strain or Prelog strain. The simplest examples of angle strain are small cycloalkanes such as cyclopropane and cyclobutane. Ring strain energy can be attributed to the energy required for the distortion of bond and bond angles in order to close a ring. Ring strain energy is believed to be the cause of accelerated rates in altering ring reactions. Its interactions with traditional bond energi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclopropanes
Cyclopropanes are a family of organic compounds containing the cyclopropyl group. The parent is cyclopropane (). Synthesis and reactions Most cyclopropanes are not prepared from the parent cyclopropane, which is somewhat inert. Instead, yclopropyl groups are often prepared by cyclization of 1,3-difunctional alkanes. An example of the former, cyclopropyl cyanide is prepared by the reaction of 4- chlorobutyronitrile with a strong base. Phenylcyclopropane is produced analogously from the 1,3-dibromide. A second major route to cyclopropanes entails addition of methylene (or its substituted derivatives) to an alkene, a process called cyclopropanation. Substituted cyclopropanes undergo the reactions associated with the cyclopropyl ring or the substituents. Vinylcyclopropanes are a special case as they undergo vinylcyclopropane rearrangement. Simple substituted cyclopropanes * Chlorocyclopropane * Cyclopropane carboxylic acid * Cyclopropyl amine * Cyclopropyl cyanide * Cycloprop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bent Bond
In organic chemistry, a bent bond, also known as a banana bond, is a type of covalent chemical bond with a geometry somewhat reminiscent of a banana. The term itself is a general representation of electron density or configuration resembling a similar "bent" structure within small ring molecules, such as cyclopropane (C3H6) or as a representation of double or triple bonds within a compound that is an alternative to the sigma and pi bond model. Small cyclic molecules Bent bonds are a special type of chemical bonding in which the ordinary hybridization state of two atoms making up a chemical bond are modified with increased or decreased s-orbital character in order to accommodate a particular molecular geometry. Bent bonds are found in strained organic compounds such as cyclopropane, oxirane and aziridine. In these compounds, it is not possible for the carbon atoms to assume the 109.5° bond angles with standard sp3 hybridization. Increasing the p-character to sp5 (i.e. s- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycloalkane
In organic chemistry, the cycloalkanes (also called naphthenes, but distinct from naphthalene) are the ring (chemistry), monocyclic Saturated and unsaturated compounds, saturated hydrocarbons. In other words, a cycloalkane consists only of hydrogen and carbon atoms arranged in a structure containing a single ring (possibly with side chains), and all of the carbon-carbon bonds are single bond, single. The larger cycloalkanes, with more than 20 carbon atoms are typically called ''cycloparaffins''. All cycloalkanes are isomers of alkenes. The cycloalkanes without side chains (also known as monocycloalkanes) are classified as small (cyclopropane and cyclobutane), common (cyclopentane, cyclohexane, and cycloheptane), medium (cyclooctane through cyclotridecane), and large (all the rest). Besides this standard definition by IUPAC, the International Union of Pure and Applied Chemistry (IUPAC), in some authors' usage the term ''cycloalkane'' includes also those saturated hydrocarbons th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
August Freund
August Freund (30 July 1835 – 28 February 1892) was an Austrian chemist who in 1881 first synthesised cyclopropane. Freund was born in 1835 in the town of Kęty, Austria-Hungary. (The town now lies in Poland.) After graduating from the gymnasium (an advanced secondary school) in Cieszyn (then in Austria-Hungary, now on the Polish border with the Czech Republic), he studied pharmacy in Lviv (then in Austria-Hungary, now in Ukraine) and then in Leipzig, Germany. After studying at Lviv University from 1856-1858, he received a master's degree in pharmacy. He then assisted professor Leopold von Pebal in his investigations of petroleum. By 1861, he was teaching at a gymnasium in Ternopil (then in Austria-Hungary, now in Ukraine). By 1869, he was appointed a professor at the realschule (secondary school) in Lviv. He then began working towards a doctoral degree, receiving a doctorate from Leipzig University in 1871. In 1872, he became a professor of chemistry at the Lviv Techni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AMPA Receptor
The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA receptor, AMPAR, or quisqualate receptor) is an ionotropic receptor, ionotropic glutamate receptor (iGluR) and predominantly sodium ion channel that mediates fast excitatory neurotransmission in the Central nervous system, central nervous system (CNS). Its activation by the neurotransmitter Glutamate (neurotransmitter), glutamate facilitates rapid neuronal communication, essential for various brain functions, including learning and memory. Its name is derived from the ability to be activated by the artificial glutamate analog AMPA. The receptor was initially named the "Quisqualic acid, quisqualate receptor" by Watkins and colleagues after the naturally occurring agonist quisqualic acid, quisqualate. Later, the receptor was designated as the "AMPA receptor" following the development of the selective agonist AMPA by Tage Honore and colleagues at the Royal Danish School of Pharmacy in Copenhagen. The ''GRIA2''- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Symmetry
In chemistry, molecular symmetry describes the symmetry present in molecules and the classification of these molecules according to their symmetry. Molecular symmetry is a fundamental concept in chemistry, as it can be used to predict or explain many of a molecule's chemical property, chemical properties, such as whether or not it has a molecular dipole moment, dipole moment, as well as its allowed spectroscopy, spectroscopic transitions. To do this it is necessary to use group theory. This involves classifying the states of the molecule using the irreducible representations from the character table of the symmetry group of the molecule. Symmetry is useful in the study of molecular orbitals, with applications to the Hückel method, to ligand field theory, and to the Woodward–Hoffmann rules. Many university level textbooks on physical chemistry, quantum chemistry, spectroscopy and inorganic chemistry discuss symmetry. Another framework on a larger scale is the use of crystal sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NMDA Receptor Antagonist
NMDA receptor antagonists are a class of drugs that work to receptor antagonist, antagonize, or inhibit the action of, the NMDA, ''N''-Methyl-D-aspartate receptor (NMDA receptor, NMDAR). They are commonly used as anesthetics for humans and animals; the state of anesthesia they induce is referred to as dissociative anesthesia. Several synthetic opioids function additionally as NMDAR-antagonists, such as pethidine, levorphanol, methadone, dextropropoxyphene, tramadol, and ketobemidone. Some NMDA receptor antagonists, such as ketamine, dextromethorphan (DXM), phencyclidine (PCP), methoxetamine (MXE), and nitrous oxide (N2O), are sometimes used as recreational drugs, for their dissociative, hallucinogenic, and euphoriant properties. When used recreationally, they are classified as dissociative drugs. Uses and effects NMDA receptor antagonists induce a state called dissociative drug, dissociative anesthesia, marked by catalepsy, amnesia, and analgesia. Ketamine is a favored anesthet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inhalational Anesthetic
An inhalational anesthetic is a chemical compound possessing general anesthetic properties that is delivered via inhalation. They are administered through a face mask, laryngeal mask airway or tracheal tube connected to an anesthetic vaporiser and an anesthetic delivery system. Agents of significant contemporary clinical interest include volatile anesthetic agents such as isoflurane, sevoflurane and desflurane, as well as certain anesthetic gases such as nitrous oxide and xenon. List of inhalational anaesthetic agents Currently-used agents * Desflurane * Isoflurane * Nitrous oxide * Sevoflurane * Xenon Previously-used agents Although some of these are still used in clinical practice and in research, the following anaesthetic agents are primarily of historical interest in developed countries: * Acetylene * Chloroethane (ethyl chloride) * Chloroform * Cryofluorane * Cyclopropane * Diethyl ether * Divinyl ether * Enflurane * Ethylene * Fluroxene * Halothane (still wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coulson Moffit Model
Coulson is both a surname and a given name. Notable people with the name include: Surname: *Andy Coulson (born 1968), English journalist and political strategist *Bernie Coulson (born 1965), Canadian actor * Bob Coulson (1887–1953), American baseball player * Catherine E. Coulson (1943–2015), American actress *Charles Coulson (1910–1974), British applied mathematician, theoretical chemist and religious author * Charlie Coulson (born 1996), English footballer *Christian Coulson (born 1978), English actor * Danny Coulson (born 1941), American law enforcement official, Deputy Assistant Director of the FBI * D'Arcy Coulson (1908–1996), Canadian ice hockey player and hotelier * Elizabeth Coulson (born 1954), Illinois politician * Elizabeth Kerr Coulson (1819–1876), English novelist * Frederick Coulson, rugby footballer * Gustavus Coulson VC (1879–1901), British Army officer * Ivar "Pop" Coulson, American inventor of the malted milkshake * John Coulson (1910–1990), British pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bond Angle
Molecular geometry is the three-dimensional arrangement of the atoms that constitute a molecule. It includes the general shape of the molecule as well as bond lengths, bond angles, torsional angles and any other geometrical parameters that determine the position of each atom. Molecular geometry influences several properties of a substance including its reactivity, polarity, phase of matter, color, magnetism and biological activity. The angles between bonds that an atom forms depend only weakly on the rest of a molecule, i.e. they can be understood as approximately local and hence transferable properties. Determination The molecular geometry can be determined by various spectroscopic methods and diffraction methods. IR, microwave and Raman spectroscopy can give information about the molecule geometry from the details of the vibrational and rotational absorbance detected by these techniques. X-ray crystallography, neutron diffraction and electron diffraction can give molecu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Society Of Chemistry
The Royal Society of Chemistry (RSC) is a learned society and professional association in the United Kingdom with the goal of "advancing the chemistry, chemical sciences". It was formed in 1980 from the amalgamation of the Chemical Society, the Royal Institute of Chemistry, the Faraday Society, and the Society for Analytical Chemistry with a new Royal Charter and the dual role of learned society and professional body. At its inception, the Society had a combined membership of 49,000 in the world. The headquarters of the Society are at Burlington House, Piccadilly, London. It also has offices in Thomas Graham House in Cambridge (named after Thomas Graham (chemist), Thomas Graham, the first president of the Chemical Society) where ''RSC Publishing'' is based. The Society has offices in the United States, on the campuses of The University of Pennsylvania and Drexel University, at the University City Science Center in Philadelphia, Pennsylvania, in both Beijing and Shanghai, People' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
