Triaza tricyclic ring system

Peng, G., Sohn, A., and Gallop, M. A. (1999) Stereoselective solid-phase synthesis of a triaza tricyclic ring system a new chemotype for lead discovery. J. Org. Chem. 64,8342-8349. 

Solid-Phase Synthesis of a Triaza Tricyclic Ring System... 

Conformationally constrained triazacyclopenta[c]penta-lenes 128 are unprecedented tricyclic scaffolds and share the structural complexity characteristic of alkaloid natural products, such as triquinanes ° (e.g., 129 and 130), in that both scaffolds are composed entirely of fused five-membered rings and contain quaternary carbon centers (Figure 16.12). The triaza tricyclic ring system represents a source of chemical diversity that may complement traditional classes of heterocyclic compounds as potential pharmaceutical agents. 

Fluorous aminoesters have also been used in DOS of three unique triaza tricyclic and tetracyclic ring systems (Scheme 22) [44], Bicyclic pyrrolidines 12 generated from one-pot, three-component 1,3-dipolar cycloaddition of azomethine ylides were further converted to hydantoin-, piperazinedione-, and benzodiazepine-fused compounds 31-33, respectively. Each of these three heterocyclic scaffolds has four stereocenters on the central pyrrolidine ring and up to four points of diversity (R1 to R4). The structure of compound... 

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