Ring pendant amino groups

Other hardeners contain heterocyclic rings which remain intact, but unlike the s-triazines do not constitute the protein link. For example, the bis-pyridinium ion (7) exerts its hardening action by acylation of pendant amino groups (Scheme 3) (70USP3542558). 

Buchwald and co-workers developed a simple method for the preparation of medium ring heterocycles (7-, 8-, 9-, and 10-membered). The process employs a Cu-catalyzed coupling of a ) -lactam with an aryl bromide or iodide followed by intramolecular attack of a pendant amino group (Scheme 4.11). In some instanees, the intermediate -lactam was observable but can be converted to the aza-heteroeyele by catalysis. Acetic acid was found to be superior to transition metal eomplexes as a catalyst for this ring-expansion process. 

Acylketene generation by dioxinone thermolysis with cyclization on a pendant amino group together with an intramolecular Diels—Alder forms a large ring lactam used as a precursor to hirsutellone B (Eqn (4.113)). ... 

Guidelines for the synthesis of cyclopeptides have it that pendant groups should be connected to the cyclic scaffold after ring closure. Moreover, peptide bond formation is generally preferred to ester bond formation as a means to accomplish macrocyclization of depsipeptide frameworks, and it is also well established that primary amino groups react more efficiently than secondary ones in peptide bond forming reactions i.e., secondary amides are more readily formed than tertiary ones. Retrosynthetic dissection of the only pair of secondary amide bonds in luzopeptin A-C precursor 11 leads to pentadepsipeptide 12 (Scheme 3). 

Functional amino AA-PEAs have also been successfully designed and synthesized using L-serine as a source of pendant hydroxyl groups. The synthesis was based on a A-carboxyanhydride ring-opening reaction that allowed the incorporation of serine residues and a typical solution polycondensation using a p-nitrophenyl-activated dicarboxylate... 

Polymers with pendant or in-chain electronically isolated photoactive groups with large 7i-electron systems, for example, aromatic amino groups, like carba-zole or condensed aromatic rings, like anthracene... 

---