Scheme 4, the reaction pathway of FOX-7 with carbohydrazide to form a
ring
In figure 6, the other amino group on the IM11 molecule continues to be
substituted by the -NHNHC=ONHNH2 group and does not
react with the second FOX-7. The formation of IM12’ is through the
rotation of the dihedral angle of -NHNHC =ONHNH2 group
on IM11, and the subsequent C-N bond binding and ring formation reaction
are facilitated by the rotation of the dihedral angle to the appropriate
position. The N on the amino group of the -NHNHC=ONHNH2group of IM12’ is bonded with C on the alkenyl group to form a
six-membered ring structure and H transfer process is proceeded
synchronously, resulting in formation of IM13’. Since IM13’ is unstable,
IM13’ is decomposed into NH3 and the cyclic product
IM14’. It can be seen that the energy barrier of TS13’ is higher than
that of TS12, and the two amino reaction sites of CHZ are tend to react
with two FOX-7s respectively, but not easily to form a ring reaction
with the two amino groups of one FOX-7.