Nitrogen bases, solid-supported

A 9-phenylfluoren-9-yl polystyrene-based resin has been described for the attachment of nitrogen and oxygen nucleophiles. Greater acid stability compared to the standard trityl resins that are widely used in solid-phase peptide synthesis make this solid support an interesting alternative in solid-phase organic synthesis. This resin can be used in Suzuki coupling reactions to furnish biaryls in good yields [100]. 

Once the sample reaches the chromatographic column, the separation process starts. The time necessary for a component injected into the chromatographic column to elute is called the absoiute retention time tR. The separation is based on different retention times of the components of the mixture. These retention times are different because the partition of each analyte between the two phases, the gas phase in motion and the stationary phase, are different. Hydrogen, helium, and nitrogen are common gases used as mobile phase. Two basic types of columns are known packed columns containing solid support particles coated with the stationary phase, and open-tubular columns with the stationary phase as a film on the inner wall (capillary columns). Because the retention time tpfi) of the analyte i is temperature dependent, the chromatographic column of any (GC) is put in an oven with temperature control capability. 

Backbone amide linker (BAL), a linker moiety for an approach to solid-phase synthesis of C-terminal-modified and cyclic peptides. The growing peptide is anchored via a backbone nitrogen that allows considerable flexibility in management of the C- and N-termini. The tris(alkoxy)benzylamide-based handle/support has been success-fiilly used as BAL [K. J. Jensen et al., J. Am. Chem. Soc. 1998, 120, 5441],... 

The substitution of oxygen by nitrogen in PO4 tetrahedron has allowed the synthesis of a new family of solids with original properties the nitrided phosphates. These systems (e.g., AlPON, AlGaPON) with tunable acid-base properties are used in a growing number of intermediate and fine chemistry production processes [204] as well as supports in heterogeneous catalysis (e.g., dehydrogenation reactions) [205]. 

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