Non-Catalyzed Click Reactions of ADIBO Derivatives with 5-Methyluridine Azides and Conformational Study of the Resulting Triazoles.

Copper-free click reactions between a dibenzoazocine derivative and azides derived from 5-methyluridine were investigated. The non-catalyzed reaction yielded both regioisomers in an approximately equivalent ratio. The NMR spectra of each regioisomer revealed conformational isomery. The ratio of isomers was dependent on the type of regioisomer and the type of solvent. The synthesis of various analogs, a detailed NMR study and computational modeling provided evidence that the isomery was dependent on the interaction of the azocine and pyrimidine parts.

Benzhydrylamines via base-mediated intramolecular sp(3) C-arylation of N-benzyl-2-nitrobenzenesulfonamides--advanced intermediates for the synthesis of nitrogenous heterocycles.

N-Benzyl-2-nitrobenzenesulfonamides underwent base-mediated intramolecular arylation at the benzyl sp(3) carbon to yield benzhydrylamines. The presence of electron withdrawing groups on the aromatic ring of the benzyl group was required to facilitate the C-arylation. Unsymmetrically substituted benzhydrylamines are advanced intermediates toward nitrogenous heterocycles, as exemplified in the syntheses of indazole oxides and quinazolines.

Base-mediated intramolecular C- and N-arylation of N,N-disubstituted 2-nitrobenzenesulfonamides: advanced intermediates for the synthesis of diverse nitrogenous heterocycles.

Structural and electronic features that facilitate and direct the intramolecular C- and N-arylation of 2-alkyl-2-{[N-(benzyl)-2-nitrophenyl]sulfonamido}acetic acid esters and amides were examined. The substitution pattern and amino acid carboxy-terminal functionality determined the arylation position. C/N-arylated products represent advanced intermediates for combinatorial synthesis of diverse nitrogenous heterocycles, including indazoles, quinazolinones, quinoxalinones, and 3-amino-2-oxindoles.

Directed solid-phase synthesis of trisubstituted imidazo[4,5-c]pyridines and imidazo[4,5-b]pyridines.

An efficient method is described for the solid-supported synthesis of imidazo[4,5-b]pyridines and imidazo[4,5-c]pyridines from 2,4-dichloro-3-nitropyridine. The key pyridine building block was reacted with polymer-supported amines, followed by replacement of the second chlorine with amines, nitro group reduction, and imidazole ring closure with aldehydes. Depending on the combination of polymer-supported and solution-phase reagents, the strategy allowed for the simple preparation of the target trisubstituted derivatives with variable positioning of the pyridine nitrogen atom. Additionally, after a slight modification of the method, the preparation of strictly isomeric imidazopyridines was possible.