Study of formation of the spiro-Meisenheimer adduct of NN′-dimethyl-N-(2,4,6-trinitrophenyl)glycinamide and its rearrangement to 2-methylamino-N-methyl-N-(2,4,6-trinitrophenyl)acetamide

Abstract

NN′-Dimethyl-N-(2,4,6-trinitrophenyl)glycinamide (5) is cyclized in methanol under specific base catalysis and gives the spiro-adduct (6). The spiro-adduct is opened by the action of methanolic hydrogen chloride to give the Z- and E-isomers of 2-methylamino-N-methyl-N-(2,4,6-trinitrophenyl)-acetamide hydrochloride (7). In aniline-anilinium chloride buffers the E-isomer of (7) is cyclized to the spiro-adduct (6) with a half-life <1 s, the rate-limiting step of the cyclization of Z-(7) isomer being its isomerization to E-(7). In methanolic acetate buffers the rate-limiting step is gradually shifted to the isomerization of the neutral (Z)-2-methylamino-N-methyl-N-(2,4,6-trinitrophenyl)acetamide Z-(8) to the E-(8) isomer.