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Methylphosphonic Acid
Methylphosphonic acid is an organophosphorus compound with the chemical formula CH3P(O)(OH)2. The phosphorus center is tetrahedral and is bonded to a methyl group, two OH groups and an oxygen. Methylphosphonic acid is a white, non-volatile solid that is poorly soluble in organic solvent but soluble in water and common alcohols. Preparation Methylphosphonic acid can be prepared from triethylphosphite by first using a Michaelis-Arbuzov reaction to generate the phosphorus(V) centre: :CH3Cl + P(OC2H5)3 → CH3PO(OC2H5)2 + C2H5Cl The resulting dialkylphosphonate is then treated with chlorotrimethylsilane before hydrolysis of the siloxyphosphonate to generate the desired product. :CH3PO(OC2H5)2 + 2 Me3SiCl → CH3PO(OSiMe3)2 + 2 C2H5Cl :CH3PO(OSiMe3)2 + 2H2O → CH3PO(OH)2 + 2 HOSiMe3 The reaction pathway proceeds via the siloxyphosphonate intermediate due to the difficulty in directly hydrolysing dialkylphosphonates. Katritzky and co-workers published a one-po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organophosphorus Compound
Organophosphorus compounds are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment. Some organophosphorus compounds are highly effective insecticides, although some are extremely toxic to humans, including sarin and VX nerve agents. Organophosphorus chemistry is the corresponding science of the properties and reactivity of organophosphorus compounds. Phosphorus, like nitrogen, is in group 15 of the periodic table, and thus phosphorus compounds and nitrogen compounds have many similar properties. The definition of organophosphorus compounds is variable, which can lead to confusion. In industrial and environmental chemistry, an organophosphorus compound need contain only an organic substituent, but need not have a direct phosphorus-carbon (P-C) bond. Thus a large proportion of pesticides (e.g., malathion), are often included in this class of compounds. Phosphorus can adopt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrahedral
In geometry, a tetrahedron (plural: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular faces, six straight edges, and four vertex corners. The tetrahedron is the simplest of all the ordinary convex polyhedra and the only one that has fewer than 5 faces. The tetrahedron is the three-dimensional case of the more general concept of a Euclidean simplex, and may thus also be called a 3-simplex. The tetrahedron is one kind of pyramid, which is a polyhedron with a flat polygon base and triangular faces connecting the base to a common point. In the case of a tetrahedron the base is a triangle (any of the four faces can be considered the base), so a tetrahedron is also known as a "triangular pyramid". Like all convex polyhedra, a tetrahedron can be folded from a single sheet of paper. It has two such nets. For any tetrahedron there exists a sphere (called the circumsphere) on which all four vertices lie, and another sphere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triethylphosphite
Triethyl phosphite is an organophosphorus compound with the formula P(OCH2CH3)3, often abbreviated P(OEt)3. It is a colorless, malodorous liquid. It is used as a ligand in organometallic chemistry and as a reagent in organic synthesis The molecule features a pyramidal phosphorus(III) center bound to three ethoxide groups. Its 31P NMR spectrum features a signal at around +139 ppm vs phosphoric acid standard. Triethylphosphite is prepared by treating phosphorus trichloride with ethanol in the presence of a base, typically a tertiary amine: :PCl3 + 3 EtOH + 3 R3N → P(OEt)3 + 3 R3NH + Cl− In the absence of the base, the reaction affords diethylphosphite ((EtO)2P(O)H). Of the many related compounds can be prepared similarly, triisopropyl phosphite is an example (b.p. 43.5 °C/1.0 mm; CAS# 116-17-6). As a ligand In coordination chemistry and homogeneous catalysis, triethylphosphite finds use as a soft ligand. Its complexes are generally lipophilic and feature met ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The New Journal For Organic Synthesis
''The'' () is a grammatical article in English, denoting persons or things already mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite article in English. ''The'' is the most frequently used word in the English language; studies and analyses of texts have found it to account for seven percent of all printed English-language words. It is derived from gendered articles in Old English which combined in Middle English and now has a single form used with pronouns of any gender. The word can be used with both singular and plural nouns, and with a noun that starts with any letter. This is different from many other languages, which have different forms of the definite article for different genders or numbers. Pronunciation In most dialects, "the" is pronounced as (with the voiced dental fricative followed by a schwa) when followed by a consonant sound, and as (homophone of pronoun ''thee'') when followed by a v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorotrimethylsilane
Trimethylsilyl chloride, also known as chlorotrimethylsilane is an organosilicon compound ( silyl halide), with the formula (CH3)3SiCl, often abbreviated Me3SiCl or TMSCl. It is a colourless volatile liquid that is stable in the absence of water. It is widely used in organic chemistry. Preparation TMSCl is prepared on a large scale by the '' direct process'', the reaction of methyl chloride with a silicon-copper alloy. The principal target of this process is dimethyldichlorosilane, but substantial amounts of the trimethyl and monomethyl products are also obtained. The relevant reactions are (Me = CH3): : x MeCl + Si → Me3SiCl, Me2SiCl2, MeSiCl3, other products Typically about 2–4% of the product stream is the monochloride, which forms an azeotrope with MeSiCl3. Reactions and uses TMSCl is reactive toward nucleophiles, resulting in the replacement of the chloride. In a characteristic reaction of TMSCl, the nucleophile is water, resulting in hydrolysis to give the hexamethy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrolysis
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis is the cleavage of biomolecules where a water molecule is consumed to effect the separation of a larger molecule into component parts. When a carbohydrate is broken into its component sugar molecules by hydrolysis (e.g., sucrose being broken down into glucose and fructose), this is recognized as saccharification. Hydrolysis reactions can be the reverse of a condensation reaction in which two molecules join into a larger one and eject a water molecule. Thus hydrolysis adds water to break down, whereas condensation builds up by removing water. Types Usually hydrolysis is a chemical process in which a molecule of water is added to a substance. Sometimes this addition causes both the substance and w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alan R
Alan may refer to: People * Alan (surname), an English and Turkish surname * Alan (given name), an English given name **List of people with given name Alan ''Following are people commonly referred to solely by "Alan" or by a homonymous name.'' *Alan (Chinese singer) (born 1987), female Chinese singer of Tibetan ethnicity, active in both China and Japan *Alan (Mexican singer) (born 1973), Mexican singer and actor * Alan (wrestler) (born 1975), a.k.a. Gato Eveready, who wrestles in Asistencia Asesoría y Administración *Alan (footballer, born 1979) (Alan Osório da Costa Silva), Brazilian footballer *Alan (footballer, born 1998) (Alan Cardoso de Andrade), Brazilian footballer *Alan I, King of Brittany (died 907), "the Great" *Alan II, Duke of Brittany (c. 900–952) * Alan III, Duke of Brittany(997–1040) *Alan IV, Duke of Brittany (c. 1063–1119), a.k.a. Alan Fergant ("the Younger" in Breton language) *Alan of Tewkesbury, 12th century abbott *Alan of Lynn (c. 1348–1423), 15th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
One-pot Synthesis
In chemistry a one-pot synthesis is a strategy to improve the efficiency of a chemical reaction whereby a reactant is subjected to successive chemical reactions in just one reactor. This is much desired by chemists because avoiding a lengthy separation process and purification of the intermediate chemical compounds can save time and resources while increasing chemical yield. An example of a one-pot synthesis is the total synthesis of tropinone or the Gassman indole synthesis. Sequential one-pot syntheses can be used to generate even complex targets with multiple stereocentres, such as oseltamivir, which may significantly shorten the number of steps required overall and have important commercial implications. A sequential one-pot synthesis with reagents added to a reactor one at a time and without work-up is also called a telescoping synthesis. In one such procedure the reaction of 3-N-tosylaminophenol I with acrolein II affords a hydroxyl substituted quinoline III through 4 seq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphonic Acids
In organic chemistry, phosphonates or phosphonic acids are organophosphorus compounds containing groups (where R = alkyl, aryl, or just hydrogen). Phosphonic acids, typically handled as salts, are generally nonvolatile solids that are poorly soluble in organic solvents, but soluble in water and common alcohols. Many commercially important compounds are phosphonates, including glyphosate (the active molecule of the herbicide Roundup), and ethephon, a widely used plant growth regulator. Bisphosphonates are popular drugs for treatment of osteoporosis.Svara, J.; Weferling, N.; Hofmann, T. "Phosphorus Compounds, Organic," in ''Ullmann's Encyclopedia of Industrial Chemistry'', Wiley-VCH, Weinheim, 2008. . In biochemistry and medicinal chemistry, phosphonate groups are used as stable bioisoteres for phosphate, such as in the antiviral nucleotide analog, Tenofovir, one of the cornerstones of anti-HIV therapy. And there is an indication that phosphonate derivatives are "promis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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