C10H12N2O2, M-r = 191.21, P2(1), a = 5.5771(7), b=27.841(3), c=6.906(1)(a) over circle, beta=111.937(9)degrees, Z=4, R-1 = 0.0462. The two independent molecules in the asymmetric unit are linked through two very strong quasi centrosymmetric hydrogen bonds. The oxadiazinone rings, of both molecules, show the pyramidal inversion at N-4 nitrogen, thus resulting in a C(R)N(S)-C(R)N(R) diastereomeric pair. The analysis of the IR N-H stretching band (in the solid and in carbon tetrachloride solution) and the C-13 NMR experiment at low temperature are in agreement with the Xray crystal structure.o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.2213226230