Solid-Phase Synthesis of Pyrazolopyridines from Polymer-Bound Alkyne and Azomethine Imines

Abstract

Study was made of the 1,3-dipolar cycloaddition of polymer-bound alkynes to azomethine imines generated in situ from N-aminopyridine iodides. Aromatization of the cycloadducts gives polymer-bound pyrazolopyridines that can be released from the resin as carboxylic acids with trifluoroacetic acid or as methyl esters with sodium methoxide.

N-Succinimidyl 3-((4-(4-[18F]fluorobutyl)-1H-1,2,3-triazol-1-yl)methyl)-5-(guanidinomethyl)benzoate ([18F]SFBTMGMB): a residualizing label for 18F-labeling of internalizing biomolecules

“…This amount itself was probably too large a quantity to avoid HPLC co-elution. Attempts were made to scavenge the unreacted azide precursor by click reaction with a polymer-bound alkyne that we synthesized by coupling propiolic acid to 4-(bromomethyl)phenoxymethyl polystyrene following a reported procedure 28 . Parenthetically, while this work was in progress, a similar strategy for scavenging excess alkyne-modified peptide with a immobilized azide was reported.…”

The first examples of chemical modification of oligomycin A

“…19 However, we could not find the examples of the interaction of 1-aminopyridine with the double bond-containing compounds followed by spontaneous dehydrogenation. Still, there are examples of the interaction of 1-aminopyridine with double bond-containing compounds substituted at the double bond with groups that are split off in the reaction producing pyrazolo [1,5-a]pyridine derivatives.…”

Six‐Membered Heterocycles: Quinoline and Isoquinoline

“…The reaction of the salt 333 with DMAD in the presence of triethylamine occurs via methylide 334 to yield pyrroloisoquinoline 335. Quaternary isoquinolinium ylides such as isoquinoline azomethine imine 336, generated in situ from 2-aminoisoquinolinium iodide (337), react with polymer-bound alkyne 338 to give pyrazoloisoquinolines 339 after cleavage from the resin [451].…”