Département de chimie moléculaire

Abstract [4674-68-4] C₂H₄N₂ (MW 56.07) InChI = 1S/C₂H₄N₂/c1-4-2-3/h4H,1H3 InChIKey = MCLITRXWHZUNCQ-UHFFFAOYSA-N (reagent used for the synthesis of 2-N-methylaminooxazoles, hydantoins, and related heterocycles) Physical Data: mp between −50 and −40 °C; bp not described because of its spontaneous trimerization above its mp; density unknown. Possible use as a stabilizer for the storage of organic isocyanates. Solubility: soluble in H₂O, alcohol, ether, and most organic solvents. Form Supplied in: colorless liquid; not commercially available. Preparative Methods: often prepared by the Von Braun synthesis involving addition of methylamine to cyanogen bromide in an ethereal solution. Other preparation methods involve the addition of methylamine to cyanogen chloride, or to potassium cyanide in the presence of bromine, or to μ-disulfido dicarbonic acid dinitrile. Treatment of methyl thiourea by lead (IV) oxide or by silver(I) oxide, or of cyanamide by dimethyl sulfate in a methanolic solution of sodium methoxide or in water have also been described. The title compound is obtained either by decomposition of 1-methyl-5-tetrazolyllithium or by chlorination of a suitable isothiourea. Purification: it is best achieved by removal of the solvent below 5 °C without light to limit the formation of trimethylisomelamine Handling, Storaege, and Precautions since trimerization of liquid methyl cyanamide occurs readily above its melting point, it may be preserved as crystals by cooling with Dry Ice. Toxic.