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Diazomethane is an organic chemical compound with the formula CH 2 N 2, discovered by German chemist Hans von Pechmann in 1894. It is the simplest diazo compound.In the pure form at room temperature, it is an extremely sensitive explosive yellow gas; thus, it is almost universally used as a solution in diethyl ether.
The reaction was originally carried out in diethyl ether and routinely generated high yields due to the inherent irreversibly of the reaction caused by the formation of nitrogen gas. Though these reactions can be carried out at room temperature, the rate does increase at higher temperatures.
Diazo compounds can be obtained in an elimination reaction of N-alkyl-N-nitroso compounds, [14] such as in the synthesis of diazomethane from Diazald or MNNG: (The mechanism shown here is one possibility. [15] For an alternative mechanism for the analogous formation of diazomethane from an N-nitrososulfonamide, see the page on Diazald.)
Diazomethane: CH 2 N 2: −23 −145 42 ... F is a gas but decomposes over several hours ... Perfluoroethyl 2,2,2-trifluoroethyl ether 27.89 °C;
Diazomethane reacts with the electron-poor ethyl acrylate more than a million times faster than the electron rich butyl vinyl ether. [ 17 ] This type resembles the normal-electron-demand Diels-Alder reaction, in which the diene HOMO combines with the dienophile LUMO.
It also reacts with alcohols to give methyl ethers, whereas diazomethane may not. [8] The compound is a reagent in the Doyle–Kirmse reaction with allyl sulfides and allyl amines. Trimethylsilyldiazomethane is deprotonated by butyllithium: (CH 3) 3 SiCHN 2 + BuLi → (CH 3) 3 SiCLiN 2 + BuH. The lithio compound is versatile.
If excess diazomethane is present during the reaction, it can act as a base, abstracting a hydrogen from the diazonium-salt intermediate. The result is a neutral diazoketone, which does not react with the chloride. Instead, the byproduct, diazonium-methyl from the other diazomethane molecule, can be attacked by the chloride to produce ...
Diazomethane is a popular methylating agent in the laboratory, but it is too hazardous (explosive gas with a high acute toxicity) to be employed on an industrial scale without special precautions. [7] Use of diazomethane has been significantly reduced by the introduction of the safer and equivalent reagent trimethylsilyldiazomethane. [8]