Nc1nc(N)c(C=O)c(N)n1    mol7531    0_1
Nc1nc(N)c(C=O)c([NH3+])n1    mol7531    1_1
Nc1nc(N)c(C=O)c(N)[nH+]1    mol7531    1_2
Nc1nc([NH3+])nc(N)c1C=O    mol7531    1_3