Structure/Logic Intermediate Form

Structure/Logic Intermediate Form (SLIF) At the logic level, the internal... 

The structural and kinetic data suggest a mechanism in which the first phosphoryl transfer step occurs by attack of the nitrogen atom of histidine accompanied by general acid assistance by the Asp carboxyl group. A logical assumption is that the carboxylate form of the Asp residue then acts as a general base to deprotonate a nucleophilic water molecule in the second step, which is hydrolysis of the phosphohistidine intermediate (Figure 8). 

If one of these bonds is to be disconnected, a reaction (or sequence of reactions) must be available that will chemically form that bond in the synthesis. Subsequent simplifications (disconnections) lead ultimately to a molecule that can be recognized as commercially available, available by simple chemical techniques, or already prepared by others. This process of structural simplification via disconnection leads to a series of molecular fragments that serve as key intermediates, and each is a synthetic target. Such intermediates allow the synthetic chemist to mentally bridge the starting material with the final target in a logical and sequential manner. This process therefore constitutes a synthetic tree for which chemical reactions must be provided to accomplish the planned transformations. 

---