title: The ring-chain tautomeric equilibria of selenium macrocyclic compounds: the isolation of the ring tautomer.
abstract: A broadening of the investigation of the ring-chain tautomeric process of N-substituted 1,3-X,N-heterocycles (X = O, S, NR) to Se containing macrocyclic compounds allowed the isolation and structurally solid state characterization of the cyclic tautomer 7, which due to the length of the aliphatic chain, is able to form a stable six-membered ring (6-endo-trig). The theoretical calculations based on the DFT method (Gaussian 03 software package) also support the fact that tautomer 7 is more stable than the chain tautomer 6. Thus, based on the ring-chain tautomerism of the macrocycles that contain alkyl chains with amino-imino, imino-alcohol or sulphur-imino groups, combined with a strategy that allows the formation of a stable six-membered ring, the main reaction products will be the cyclic tautomers. The ring-chain equilibria of these macrocycles could be exploited advantageously in different areas of macrocyclic, physical and medicinal chemistry in order to obtain compounds with practical applications.
authors.affiliation: Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, 11 Arany Janos Str., 400056 Cluj-Napoca, Cluj, Romania.
authors.forename: Monica
authors.initials: M
authors.lastname: Bucşa
authors.forename: Alpár
authors.initials: A
authors.lastname: Pollnitz
authors.forename: Richard A
authors.initials: RA
authors.lastname: Varga
authors.forename: Adrian
authors.initials: A
authors.lastname: Pîrnău
authors.forename: Anca
authors.initials: A
authors.lastname: Silvestru
authors.forename: Mircea
authors.initials: M
authors.lastname: Vlassa