Polystyrene supported pyridinium

PSPBP polystyrene-supported pyridinium bromide perbromide... 

Li et al. reported the first solid-phase synthesis of a DOFL based on the styryl structure." Styryl compoimds are simple fluorescent molecules that can be prepared by condensation of aldehydes and pyridinium salts. After testing a series of resins and reaction routes, the authors employed a 2-chlorotrityl polystyrene resin to load two amino alcohols with different length chains. The alcohol groups were then mesylated and subsequently treated with four picoline and three quinoline derivatives to render solid-supported pyridinium salts that were then condensed with 64 chemically diverse aldehydes under microwave irradiation (Figure 14.9a). Final cleavage with TFA-DCM (1 99) yielded a collection of 320 styryl dyes with very diverse spectral properties, and they were evaluated as amyloid probes without further purification. 

Support-bound alkylating agents have been used to N-alkylate pyridines and dihydropyridines (Entries 7 and 8, Table 15.21). Similarly, resin-bound pyridines can be N-alkylated by treatment with a-halo ketones (DMF, 45 °C, 1 h [267]) or other alkylating agents [246]. Polystyrene-bound l-[(alkoxycarbonyl)methyl]pyridinium salts can be prepared by N-alkylating pyridine with immobilized haloacetates (Entry 8, Table 15.21). These pyridinium salts react with acceptor-substituted alkenes to yield cyclopropanes (Section 5.1.3.6). Pyridinium salts have also been prepared by reaction of resin-bound primary amines with /V-(2,4-dinitrophenyl)pyridinium salts [268,269]. 

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