Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

The side reactions of N-methyl-N-(2,4-dinitrophenyl)glycine methylamide with methanolic sodium methoxide reversibly give the spiro adduct (spiro[(1,3-dimethyl-5-imidazolidone)-2,1'-(2',4'-dinitrobenzenide)]) and irreversibly produce N-methyl-2-nitroso-4-nitroaniline which undergoes subsequent reduction. The diazolidine ring of the spiro adduct is opened by action of methanolic hydrogen chloride, whereby the Smiles rearrangement is completed. The rearrangement product-2-methylamino-N-methyl-N-(2,4-dinitrophenyl)acetamide hydrochloride-is present in the form of a mixture of Z and E isomers (ratio 1.9). The equilibrium constant of formation of the spiro adduct from 2-methylamino-N-methyl-N-(2,4-dinitrophenyl)acetamide hydrochloride is by 9 orders of magnitude lower than that found for the analogous trinitrophenylderivative. The rate-limiting step of the transformation of the Z-isomer into the spiro adduct consists in the isomerization Z ⇄ E. The E-isomer is cyclized with a half-life shorter than 1 ms.