Just wanted to verify that this is the structure of 4-nitroimino-perhydro-1,3,5-oxadiazine:
O
/ \
H2C CH2
| |
HN NH
\ /
C
�?BR> N
\
NO2
Molecular formula = C3H6N4O3. Do you have access to a library where you can do a Chemical Abstracts search? If the synthesis by the condensation reaction of nitroguanidine with formaldehyde is an established procedure, it's just a matter of finding it in the chemical literature. Good luck!
Steve