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Selenoxide elimination (also called α-selenation) [1] is a method for the chemical synthesis of alkenes from selenoxides. It is most commonly used to synthesize α,β-unsaturated carbonyl compounds from the corresponding saturated analogues. [2] It is mechanistically related to the Cope reaction.
Selenocysteine, called the twenty-first amino acid, is essential for ribosome-directed protein synthesis in some organisms. [14] More than 25 selenium-containing proteins (selenoproteins) are now known. [15] Most selenium-dependent enzymes contain selenocysteine, which is related to cysteine analog but with selenium replacing sulfur.
Sample of cadmium selenide, a pigment. The parent inorganic selenide is hydrogen selenide (H 2 Se). It is a colorless, malodorous, toxic gas. It dissolves in aqueous solution, to give the hydrogenselenide or biselenide ion HSe −. At higher pH, selenide forms. Solutions of hydrogen selenide and selenide are oxidized by air to give elemental ...
The Grieco elimination is an organic reaction describing the elimination reaction of an aliphatic primary alcohol through a selenide to a terminal alkene. [1] [2] It is named for Paul Grieco. The alcohol first reacts with o-nitrophenylselenocyanate and tributylphosphine to form a selenide via a nucleophilic substitution on the electron ...
In organic chemistry, the E i mechanism (Elimination Internal/Intramolecular), also known as a thermal syn elimination or a pericyclic syn elimination, is a special type of elimination reaction in which two vicinal (adjacent) substituents on an alkane framework leave simultaneously via a cyclic transition state to form an alkene in a syn elimination. [1]
Synthesis can also be conducted in high-boiling, polar, aprotic solvents such as DMF, HMPA, and NMP. [2] These reactions appear to proceed by initial formation of the alkali metal selenide, followed by the reaction of the latter with additional selenium: 2 Na + Se → Na 2 Se Na 2 Se + n Se → Na 2 Se n+1
The compound was first synthesized in 1884 by Auguste Verneuil by the reaction of hydrogen selenide and cyanamide: [2]. H 2 Se + N≡C−NH 2 → Se=C(NH 2) 2. While this reaction has even found use in industrial synthesis of selenourea, [3] more modern methods concern themselves with synthesis of substituted selenoureas.
Methaneselenol (commonly named "methylselenol") (CH 3 SeH), which can be produced in vitro by incubating selenomethionine with a bacterial methionine gamma-lyase (METase) enzyme, by biological methylation of selenide ion or in vivo by reduction of methaneseleninic acid (CH 3 −Se(=O)−OH), has been invoked to explain the anticancer activity ...