5-Nitro-2,4-dihydro-3H-1,2,4-triazol-3-one (NTO) has been synthesized
in good yield with N-15 at the 1 and 2 positions. The N-H coupling pro
vides unequivocal assignments for H-1 and N-15 NMR spectra and the aci
dic proton. The products of thermal decomposition at 270 degrees C wer
e identified spectroscopically. NMR spectra reveal that thermal decomp
osition results in the formation of 2,4-dihydro-3H-1,2,4-triazol-3-one
and ammonia (the latter observed as ammonium ion). The production of
ammonia from the thermal decomposition of an energetic material is unp
recedented. The gas products HCN, (NN)-N-15-N-14, N-15(2), and CO were
detected by mass spectrometry. Some possible mechanisms of thermal de
composition are discussed.