Template selection

Neu5Ac2en 14 was an interesting inhibitor template with micromolar activity, but was not selective, inhibiting microbial and mammalian sialidases alike. 

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Both of these MIP preparation procedures have their advantages and limitations [20, 21]. For instance, the size of the analyte molecule is not a discriminating criterion in covalent imprinting since the template selectively determines the interaction sites. In contrast, non-covalent imprinting has the advantage of being simpler since an additional synthetic step is not required to introduce the template into the polymer matrix. Moreover, removal of the template via extraction with the suitable solvent solution is simple and mostly complete for the non-covalent imprinting. 

Further experiments, made using a template selective for position 3, permitted a high stereocontrol of the reaction involving the natural substrate cholestan-3-one (22). This was reduced to the corresponding, less readily available, cholestanol 3a-OH, with a ratio 3a-OH/3/i-OH = 72/28. The corresponding result for a hydride reduction in solution usually gave 3oc-OH/3/ -OH = 10/90. 

Scheme 6.6 Templated, selective formation of porphyrin dimer 14 [41].

Off-target Activity against unintended target(s) Secondary pharmacophore or Nonselectivity against family of related targets by primary pharmacophore Eliminate or reduce effect (may require changing structural template) Selectivity may be improved Case-by-case... 

The success in diastereoselective Lewis acid-mediated conjugate radical additions using chiral oxazolidinones led to the development of enantioselective variants. The achiral template selection was based on literature precedents for rotaraer control s-cis vs s-trans) and the requirement for a bidentate Lewis acid chiral ligand combination for obtaining selectivity (Eq. (13.51)). 

When the user exits a worksheet with a quit/save, the status of that template is determined, stored, and displayed in the template selection list. A scenario cannot be included in an analysis if any of its worksheets are incomplete. 

For each of these templates, selectivity, in terms of their ability to resolve the racemate (a), was determined and shown to correlate with the number of theoretical hydrophilic interactions between the template and MAA (Table 6. 4). 

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