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Synthesis of chiral polyazamacrocycles of variable ring size†
Seiji Kamioka,Sakae Sugiyama,Takashi Takahashi
Organic & Biomolecular Chemistry Pub Date : 04/01/2010 00:00:00 , DOI:10.1039/C001228A
Abstract

Synthesis and structure elucidation of optically active tri-, tetra-, and penta-azamacrocycles having 4-methoxyphenyl pendants are described. Regioselective ring opening of a nosylaziridine with secondary benzyl amines was repeatedly performed to afford the cyclization precursors. Intramolecular N-alkylation of N-(ω-haloalkyl) nosylamide provided tri-, tetra-, and penta-azamacrocycles. On the basis of our study of the tetra-azamacrocycle previously elucidated by X-ray single-crystal analysis and in solution by NMR analysis, we conclude that the tri-azamacrocycle does not mainly have a vase-type conformation because of the steric hindrance of the 4-methoxyphenyl groups but the penta-azamacrocycle has a vase-type conformation in CDCl3 and in CD2Cl2. The vase-type conformation of the penta-azamacrocycle is, however, not as much stable as that observed in the tetra-azamacrocycle because conformational flexibility of the penta-azamacrocycle was observed in deuterated benzene.

Graphical abstract: Synthesis of chiral polyazamacrocycles of variable ring size
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