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Stieglitz Rearrangement
The Stieglitz rearrangement is a rearrangement reaction in organic chemistry which is named after the American chemist Julius Stieglitz (1867–1937) and was first investigated by him and Paul Nicholas Leech in 1913. It describes the 1,2-rearrangement of trityl amine derivatives to triaryl imines. It is comparable to a Beckmann rearrangement which also involves a substitution at a nitrogen atom through a carbon to nitrogen shift. As an example, triaryl hydroxylamines can undergo a Stieglitz rearrangement by dehydration and the shift of a phenyl group after activation with phosphorus pentachloride to yield the respective triaryl imine, a Schiff base. In general, the term "Stieglitz rearrangement" is used to describe a wide variety of rearrangement reactions of amines to imines. Although, it is generally associated with the rearrangement of triaryl hydroxylamines, that are well-reported in the academic literature, Stieglitz rearrangements can also occur on alkylated amine derivative ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Julius Stieglitz
Julius Oscar Stieglitz (May 26, 1867 – January 10, 1937) was an American chemist of German Jewish origin. He was a teacher and organic chemist with a major interest in pharmaceutical and medicinal chemistry. He is known for the Stieglitz rearrangement, a rearrangement reaction in organic chemistry which commonly involves the formation of imines from hydroxylamines through a carbon to nitrogen shift, comparable to the key step of a Beckmann rearrangement. During the early stages of his career, he worked for Parke, Davis & Co. in Detroit as a toxicologist. After attending private and public schools in New York during his early years, both he and his twin brother Leopold were sent to Germany for their higher education. He went to the Gymnasium in Germany and studied at the University of Berlin, where he received his PhD in chemistry in 1889 with Ferdinand Tiemann. Following a short period of study with Victor Meyer at Göttingen, he returned to the U.S. in 1890. In 1892 Stieglitz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stieglitz Rearrangement Benzyloxy Substituted Amine
Stieglitz may refer to: People *Stieglitz (surname) *Alexander von Stieglitz (1814–1884) was a Russian philanthropist and financier *Alfred Stieglitz (1864–1946), American photographer **Katherine Stieglitz (1898–1971), daughter of Emmeline and Alfred Stieglitz *Joseph E. Stiglitz (born 1943), American economist, recipient of a Nobel Prize in economics *Daniel Stieglitz (born 1980), German Artist, Director, Writer Places *Stieglitz Museum of Applied Arts, museum in Saint Petersburg, Russia, founded by baron Alexander von Stieglitz * Stieglitz, Victoria, small hamlet in Brisbane Ranges National Park, Australia *Stieglitz, Tasmania, a locality in Australia See also *Focke-Wulf Fw 44 ''Stieglitz'', a German two-seat biplane *Steglitz Steglitz () is a locality of the Steglitz-Zehlendorf borough in Southwestern Berlin, the capital of Germany. is a Slavic name for the European goldfinch, similar to the German . Steglitz was also a borough from 1920 to 2000. It contained the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stieglitz Rearrangement PCl5
Stieglitz may refer to: People *Stieglitz (surname) *Alexander von Stieglitz (1814–1884) was a Russian philanthropist and financier *Alfred Stieglitz (1864–1946), American photographer **Katherine Stieglitz (1898–1971), daughter of Emmeline and Alfred Stieglitz *Joseph E. Stiglitz (born 1943), American economist, recipient of a Nobel Prize in economics *Daniel Stieglitz (born 1980), German Artist, Director, Writer Places *Stieglitz Museum of Applied Arts, museum in Saint Petersburg, Russia, founded by baron Alexander von Stieglitz * Stieglitz, Victoria, small hamlet in Brisbane Ranges National Park, Australia *Stieglitz, Tasmania, a locality in Australia See also *Focke-Wulf Fw 44 ''Stieglitz'', a German two-seat biplane *Steglitz Steglitz () is a locality of the Steglitz-Zehlendorf borough in Southwestern Berlin, the capital of Germany. is a Slavic name for the European goldfinch, similar to the German . Steglitz was also a borough from 1920 to 2000. It contained the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroxyl Group
In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy groups. Both the negatively charged anion , called hydroxide, and the neutral radical , known as the hydroxyl radical, consist of an unbonded hydroxy group. According to IUPAC definitions, the term ''hydroxyl'' refers to the hydroxyl radical () only, while the functional group is called a ''hydroxy group''. Properties Water, alcohols, carboxylic acids, and many other hydroxy-containing compounds can be readily deprotonated due to a large difference between the electronegativity of oxygen (3.5) and that of hydrogen (2.1). Hydroxy-containing compounds engage in intermolecular hydrogen bonding increasing the electrostatic attraction between molecules and thus to higher boiling and melting points than found for compounds that lack this func ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boron Trifluoride
Boron trifluoride is the inorganic compound with the formula BF3. This pungent, colourless, and toxic gas forms white fumes in moist air. It is a useful Lewis acid and a versatile building block for other boron compounds. Structure and bonding The geometry of a molecule of BF3 is trigonal planar. Its D3h symmetry conforms with the prediction of VSEPR theory. The molecule has no dipole moment by virtue of its high symmetry. The molecule is isoelectronic with the carbonate anion, . BF3 is commonly referred to as " electron deficient," a description that is reinforced by its exothermic reactivity toward Lewis bases. In the boron trihalides, BX3, the length of the B–X bonds (1.30 Å) is shorter than would be expected for single bonds, and this shortness may indicate stronger B–X π-bonding in the fluoride. A facile explanation invokes the symmetry-allowed overlap of a p orbital on the boron atom with the in-phase combination of the three similarly oriented p orbitals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphorus Pentoxide
Phosphorus pentoxide is a chemical compound with molecular formula P4 O10 (with its common name derived from its empirical formula, P2O5). This white crystalline solid is the anhydride of phosphoric acid. It is a powerful desiccant and dehydrating agent. Structure Phosphorus pentoxide crystallizes in at least four forms or polymorphs. The most familiar one, a metastable form (shown in the figure), comprises molecules of P4O10. Weak van der Waals forces hold these molecules together in a hexagonal lattice (However, in spite of the high symmetry of the molecules, the crystal packing is not a close packing). The structure of the P4O10 cage is reminiscent of adamantane with ''T''d symmetry point group. It is closely related to the corresponding anhydride of phosphorous acid, P4O6. The latter lacks terminal oxo groups. Its density is 2.30 g/cm3. It boils at 423 °C under atmospheric pressure; if heated more rapidly it can sublimate. This form can be made by condensing the vap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphorus Pentachloride
Phosphorus pentachloride is the chemical compound with the formula PCl5. It is one of the most important phosphorus chlorides, others being PCl3 and POCl3. PCl5 finds use as a chlorinating reagent. It is a colourless, water-sensitive and moisture-sensitive solid, although commercial samples can be yellowish and contaminated with hydrogen chloride. Structure The structures for the phosphorus chlorides are invariably consistent with VSEPR theory. The structure of PCl5 depends on its environment. Gaseous and molten PCl5 is a neutral molecule with trigonal bipyramidal geometry and (''D''3h) symmetry. The hypervalent nature of this species (as well as of , see below) can be explained with the inclusion of non-bonding molecular orbitals (molecular orbital theory) or resonance (valence bond theory). This trigonal bipyramidal structure persists in nonpolar solvents, such as CS2 and CCl4. In the solid state PCl5 is an ionic compound, formulated . In solutions of polar solvents, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Mechanism Stieglitz Rearrangement
A general officer is an officer of high rank in the armies, and in some nations' air forces, space forces, and marines or naval infantry. In some usages the term "general officer" refers to a rank above colonel."general, adj. and n.". OED Online. March 2021. Oxford University Press. https://www.oed.com/view/Entry/77489?rskey=dCKrg4&result=1 (accessed May 11, 2021) The term ''general'' is used in two ways: as the generic title for all grades of general officer and as a specific rank. It originates in the 16th century, as a shortening of ''captain general'', which rank was taken from Middle French ''capitaine général''. The adjective ''general'' had been affixed to officer designations since the late medieval period to indicate relative superiority or an extended jurisdiction. Today, the title of ''general'' is known in some countries as a four-star rank. However, different countries use different systems of stars or other insignia for senior ranks. It has a NATO rank scal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imidic Acid
In chemistry, an imidic acid is any molecule that contains the -C(=NH)-OH functional group. It is the tautomer of an amide and the isomer of an oxime. The term "imino acid" is an obsolete term for this group that should not be used in this context because it has a different molecular structure.{{GoldBookRef , file=I02959 , title=Imino acids , accessdate=2012-04-02 Imidic acids can be formed by metal-catalyzed dehydrogenation of geminal amino alcohols. For example, methanolamine, the parent compound of the amino alcohols, can be dehydrogenated to methanimidic acid, the parent compound of the imidic acids. :H2NCH2OH → HNCHOH + H2 (tautomer of formamide) Geminal amino alcohols with side chains similarly form imidic acids with the same side chains: :H2NCHROH → HNCROH + H2 Another way to form imidic acids is the reaction of carboxylic acids with azanone. For example, the reaction for carbamic acid: :H2NCOOH + HNO → H2NCNHOH + O2 (tautomer of urea) And the general reaction f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Borohydride
Sodium borohydride, also known as sodium tetrahydridoborate and sodium tetrahydroborate, is an inorganic compound with the formula Na BH4. This white solid, usually encountered as an aqueous basic solution, is a reducing agent that finds application in papermaking and dye industries. It is also used as a reagent in organic synthesis. The compound was discovered in the 1940s by H. I. Schlesinger, who led a team seeking volatile uranium compounds.Hermann I Schlesinger and Herbert C Brown (1945)Preparation of alkali metal compounds. US Patent 2461661. Granted on 1949-02-15; expired on 1966-02-15. Results of this wartime research were declassified and published in 1953. Properties The compound is soluble in alcohols, certain ethers, and water, although it slowly hydrolyzes. Sodium borohydride is an odorless white to gray-white microcrystalline powder that often forms lumps. It can be purified by recrystallization from warm (50 °C) diglyme. Sodium borohydride is soluble ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iminium Ion
In organic chemistry, an iminium cation is a polyatomic ion with the general structure . They are common in synthetic chemistry and biology. Structure Iminium cations adopt alkene-like geometries. The central C=N unit is nearly coplanar with all four substituents. The C=N distances, which are near 129 picometers in length, are shorter than C-N single bonds. Cis/trans isomers are observed. Formation Iminium cations are obtained by protonation and alkylation of imines: :RN=CR'_2 + H+ -> [RNH=CR'_2]+ :RN=CR'_2 + R''+ -> [RR''N=CR'_2]+ They also are generated by the condensation of secondary amines with ketones or aldehydes: :O=CR'_2 + R2NH + H+ [R2N=CR'_2]+ + H2O This rapid, reversible reaction is one step in "iminium catalysis". More exotic routes to iminium cations are known, e.g. from ring-opening reactions of pyridine. Occurrence Iminium derivatives are common in biology. Pyridoxal phosphate reacts with amino acids to give iminium derivatives. Many iminium sal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
