Figure 5. Gibbs free-energy profile for the
substitution reaction between the second FOX-7 and
CHZ
There are two reactive sites on the FOX-7 molecule that can be
substituted by CHZ. Therefore, it is necessary to verify why the pathway
of bisamino substitution into the ring is difficult to proceed. In
Scheme 4, after an amino group on FOX-7 is substituted by CHZ, another
amino group is also substituted by CHZ, and finally a six-membered ring
structure is formed.