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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.
The example below was taken from a synthesis of morphine. [4] Another characteristic reaction is chlorination: Ph 2 Se 2 + Cl 2 → 2 PhSeCl. PhSeCl is a powerful electrophile, used to introduce PhSe groups by reaction with a variety of nucleophiles, including enolates, enol silyl ethers, Grignard reagents, organolithium reagents, alkenes and ...
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 ...
Selenomethionine participates in the synthesis of selenoproteins. [2] The reduction potential and pKa (5.47) of selenocysteine are lower than those of cysteine, making some proteins have antioxidant activity. [3] Selenium compounds have important applications in semiconductors, glass and ceramic industries, medicine, metallurgy and other fields ...
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.