L. Peyrot et al., Synthesis and characterization of new heterocyclic derivatives by oxidation of 1-amino-2-methylindoline, J HETERO CH, 38(4), 2001, pp. 885-893
1-Amino-2-methylindoline is a precursor used in the synthesis of antihypert
ension drugs. It reacts with monochloramine to lead to the formation of 1-a
mino-2-methylindole and azo(2-methyl)indoline. These new products have been
isolated and characterized by microanalysis, uv, gc/ms, ir, and H-1/C-13 n
mr. The reaction leads to the transient formation of an indolic aminonitren
e. 1-Amino-2-methylindole formation proceeds in strongly alkaline medium by
rearrangement of a diaziridine intermediate. In neutral or slightly alkali
ne medium, one obtains a precipitate of tetrazene type (-N-N=N-N-), the azo
(2-methyl)indoline. The study of the thermochemical properties shows that t
etrazene decomposes towards 150 degreesC to give the 1,1'-bi(2-methyl)indol
ine. The stability of the starting reagents and products was the subject of
a systematic investigation. A reaction mechanism is proposed.