Diazomethane


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diazomethane

[dī¦a·zō′me‚thān]
(organic chemistry)
CH2N2 A poisonous gas used in organic synthesis to methylate compounds.

Diazomethane

 

the very simple acyclic diazo compound CH2N2; a highly toxic and explosive yellowish gas with an unpleasant odor. Melting point, -145°C; boiling point, -23° C. The structure of diazomethane can be represented by the following formulas: Diazomethane.

Diazomethane is usually produced by treating nitrosomethylurea (1) or nitrosomethylurethane (2) with an alkali:

Diazomethane may react with or without the liberation of nitrogen. The most important reactions of diazomethane involve the liberation of N2: the generation of carbene upon pyrolysis or photolysis of diazomethane or under the catalytic action of powdered copper:

(3) CH2N2→:CH2+N2

reactions with acids, phenols, and alcohols, with the formation of corresponding methyl ethers and esters, such as

(4) CH3COOH + CH2N2→CH3COOCH3 + N2

and interaction with halogens and halides of other elements:

Diazomethane

Diazomethane reacts without the liberation of nitrogen with such compounds as the acid halides of carboxylic acids, resulting in the production of diazoketones. When the diazoketones decompose in the presence of water, alcohols, or amines and a catalyst (Ag2O), regrouping takes place, resulting in the formation of an acid (its ester or amide) with one more carbon atom than in the initial acid chloride (the Arndt-Eistert reaction):

Diazomethane

The synthesis of carboxylic acids is one of the most important applications of diazomethane; it is also used extensively as a methylizing agent.

B. L. DIATKIN

References in periodicals archive ?
2-mL aliquot was used for the analysis of OH-BDE-47 metabolites by first derivatizing the sample with trimethylsilyl diazomethane.
Methyl esters were prepared using diazomethane in diethyl ether, and analysed by gas chromatography.
A comparable enhancement in degradability was obtained when cross-linking was reduced by methylating ferulates with diazomethane to block coupling of ferulate with monolignols during DHP-CW formation.
The purified extract was methylated using diazomethane and analysed using high-resolution gas chromatography.
The extract was concentrated to near dryness and derivatized with diazomethane to form the methyl ether of PCP.
The combined organic extracts were evaporated, and the residue was dissolved in 100 [micro]L of methanol and derivatized with 100 [micro]L of an ethereal diazomethane solution for 10 min at room temperature (2).
After isolation on a DEAE-Sephadex ion exchange column, the solution was evaporated under a stream of nitrogen gas and the residue was dissolved in 10 mL of methyl heptadecanoate internal standard and derivatized to its methyl ester form with diazomethane.
A 15 ml yellow dimethylether solution of diazomethane, ready for use and prepared by adding alcoholic solution of KOH to 300 mg of Diazald, was poured into 0.
Although the parent compound, diazomethane, was reactive, the TMS-substituted ylide gave significantly higher yields (>98% vs.
To serve its different customers Novasep Synthesis has developed know-how and innovative technologies using: Hazardous Chemistry: Azide, Diborane, Diazomethane, Ozonolysis, Carbonylation, Asymmetric technologies: Asymmetric Chemistry, Preparative Chromatography, Synthesis and Purification of Highly Potent Molecules and multi-step, multi-ton synthesis.
The OH-PCBs in the sample extracts and calibration standards were methylated by adding diazomethane that was synthesized as described elsewhere (Sandau 2000).