Knorr linkers

The reactors selected were 432 aminomethylated MicroTubes 7.63, which are polystyrene-grafted polypropylene tubes with a 50 xM loading capacity per reactor, that encapsulate a preencoded radiofrequency tag (Fig. 7.38). The tubes were reacted with the Fmoc-protected, acid-labile Knorr linker (step a), the residual amine functions... 

A wide range of benzhydryl-based linkers bearing additional electron-donating functionalities has also been developed for Fmoc SPPS of peptide amides, the most popular of which are the eponymous Rink amide (7) [13] and Knorr linkers 24 [65]. Primary amides prepared on this resin can be cleaved with TFA in the same manner as previously described for the PAL linker. 

Due to a very low capacity of the glass surface, traditional analytical tools cannot be used for adequate assessment of fidelity of the light-directed synthesis. A highly sensitive analytical method to characterize quality of peptides synthesized by this technology was developed [43]. This involves derivatization of the surface with an acid-cleavable Knorr linker (Fig. 16 1) followed by the attachment of a C-terminal chromophoric tag, Lys(Dabs) (Fig. 16 2). 

Application of the Knorr pyrazole synthesis has also been demonstrated on solid support. ° To prepare trisubstituted pyrazoles, the diketone was linked to the solid support to make 57 using a linker with an amide bond. Alkylation of the diketone followed by condensation of the hydrazine with the resulting diketone gave the desired pyrazoles as mixtures of isomers. Subsequent cleavage of the amide bond linker then provided the pyrazole amides 59. ... 

I he standard analytical construct used for library production in Diversity Sciences at GlaxoSmithKline is shown in Figure 8.1. The analytical construct uses the common Knorr acid cleavable linkers at the first and second linker positions. The terminal linker is photocleavable and is released upon exposure to 350-nM light [12-15]. The construct contains the mass-code block and uses isotopically labeled Gly as a peak splitting element to facilitate compound identification by mass spectrometry. Also, the construct has two lysine amino acid groups to aid the ionization process of both the code block and the ligand... 

O-o-V"1 gA° R X.H.C R 0 NH2 [52] Amides of different types are produced to form peptido-mimetics and/or peptoids. Not only condensation reactions but also alkylation and substitution reactions are described. Resins/linkers used Wang, Rink amide, Knorr TenlaGel. Phosphoramides were prepared on Pore glass, 3 split-pool libraries. [21] [50-57]... 

Because of the origins of solid phase chemistry in peptide synthesis, amide formation is historically one of the most important reactions on solid supports. The most pubUc resins are the Rink amide linker 123 [146,147] and its derivatives that are formed by addition of the Knorr hnker [148] to polystyrene-derived resins. 

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