Homology, structural Subject

After clavulanic acid, the penicillanic acid derivatives (particularly the corresponding sulfone analogs) have been the subject of intense research in the -lactamase inhibitor area. From this extensive investigation, two compounds (sulbactam and tazobactam) from this class have been successfully introduced into clinical use. The penicillanic acid sulfones are /3-laclamasc inhibitors that are quite homologous to clavulanate in both their mechanism of action and in the spectrum of -lactamases susceptible to their action. The first notable success in this field was the discovery of sulbactam 7 (Fig. 7), which was reported by Pfizer chemists in 1978 and shown to possess potent inhibitory activity, principally for class A //-lactamases. It had greater affinity for class C types than clavulanate. From careful comparison of its structure to clavulanate, a rational basis for the similarities between the two is apparent. Both lack a C-6 substituent. Since the absence (or presence) of this substituent is an important, but not exclusive, factor in //-lactamase recogni-... 

Oxidation studies on Athabasca and other oil sand asphaltenes have shown the presence of aliphatic sulfides in amounts of up to 25% of the total sulfur (25). The structure of these sulfides has been established using mild thermolysis to liberate them from the polymeric framework of the asphaltene molecules. The produced pyrolysis oil contains significant concentrations of the sulfides and can be readily subjected to analysis. SIR-GC/MS traces of the homologous series of sulfides identified are... 

How can there be obviousness of structure, or particularly of the subject matter as a whole, when no apparent purpose or result is to be achieved, no reason or motivation to be satisfied, upon modifying the reference compounds structure Where the prior art reference neither discloses nor suggests a utility for certain described compounds, why should it be said that a reference makes obvious to one of ordinary skill in the art an isomer, homolog or analog of related structure, when that mythical, but intensely practical, person knows of no practical reason to make the reference compounds, much less any structurally related compounds 29... 

---