ALIPHATIC DIAZO-COMPOUNDS The esters of the aliphatic amino-acids may be diazotized in a manner similar to the primary aromatic amines, a fact discovered by T. Curtius. The first aliphatic diazo-compound to be isolated was diazoacetic ester,
which is prepared by the action of potassium nitrite on the ethyl ester of glycine hydro chloride,
It is a yellowish oil which melts at —24° C; it boils at
C, but cannot be distilled safely as it decomposes vio lently, giving nitrogen and ethyl fumarate. It explodes in contact with concentrated sulphuric acid. On reduction it yields ammonia and glycine. The diazo-ester condenses with benzene and its homologues giving rise to esters containing seven-membered hy drocarbon rings (Bucherer, 1896). The constitution of the diazo fatty esters is inferred from the fact that the two nitrogen atoms, when split off, are replaced by two univalent elements or groups, thus leading to the formula
for diazoacetic ester.
was first obtained in 1894 by H. v. Pechmann. It is prepared by the action of aqueous or alcoholic solutions of the caustic alkalis on the nitroso-acidyl derivatives of methylamine (such, for example, as nitrosomethyl urethane,
which is formed on passing nitrous fumes into an ethereal solution of methyl urethane). E. Bamberger re gards it as the anhydride of iso-diazomethane,
: N•OH, and has prepared it by a method similar to that used for the prepara tion of iso-diazobenzene. By the action of bleaching powder on methylamine hydrochloride there is obtained a volatile liquid methyldichloroamine,
boiling at 58-6o° C, which ex plodes violently when heated with water, yielding hydrocyanic acid
Well-dried hydroxylamine hydro chloride is dissolved in methyl alcohol and mixed with sodium methoxide; a solution of methyldichloroamine in absolute ether is then added and an ethereal solution of diazomethane distils over. Diazomethane is a yellow inodorous gas, very poisonous and cor rosive. It may be condensed to a liquid, which boils at about o° C. It is a powerful methylating agent, reacting with water to form methyl alcohol, and converting acetic acid into methyl-acetate, hydrochloric acid into methyl chloride, hydrocyanic acid into acetonitrile, and phenol into anisole, nitrogen being eliminated in each case. It is reduced by sodium amalgam (in alcoholic solu tion) to methylhydrazine,
It unites directly with acetylene to form pyrazole.
See G. T. Morgan, B.A. Rep. (1902) ; J. Cain, The Chemistry and Technology of the Diazo-compounds (1920) ; T. E. Thorpe, Dictionary of Applied Chemistry, "Diazo-compounds" (1931). (G. T. M.)
