Metallchelate pyridyl‐(2)‐substituierter 3,7‐Diaza‐bicyclo‐[3,3,1]‐nonanone

Abstract

Riickschliisse auf die Konformation substituierter azabicyclischer Ketone konnen an Hand spektroskopischer Ergebnisse gezogen werden. 3,7-Diaza-bicyclo-[3,3,l]-nonanone-(9) mit PyridyI-(2)-Substituenten an C-2 und C-4 bilden Metallchelate mit Salzen zweiwertiger ubergangsmetalle. Die in den IR-Spektren der freien 3,7-Diaia-bicyclo-[3,3,l]-nonanone im Bereich von 2700-2800 cm-l auftretende Bandengruppe ist nach Chelatbildung verschwunden. Weiterhm sind in den IR-Spektren der Chelate die Y"H-sowie die Y 8a-Banden des Pyridinrings in charakteristischer Weise verschoben. Aus diesen Ergebnissen kann gefolgert werden, daB solche azabicyclischen Verbindungen gegenuber dem Metallion als vierziihnige Liganden reagieren.Metal chelates of pyridyl-(2)-substituted 3,7-Diaza-bicyc10[3,3,1] -nonanonee Spectroscopic results allow conclusions about the conformation of substituted azabicyclic compounds. 3,7-Diaza-bicyclo-[3,3,1]-nonanones-(9) which have pyridyL(2) substituents at C-2 and C-4 form metal chelates with salts of bivalent transition metals. The bands at 2700-2800 cm-1 in the IR-spectra of the free 3,7-diaza-bicyclo-[3,3,l]-nonanones disappear in the spectra of the metal chelates. The vNH and the v8a bands of the pyridine ring in the IR-spectra of the metal chelates are shifted in a characteristic manner. Prom these results, it can be concluded that such azabicyclic compounds react aa tetradentate ligands with the metal ion. 3,7-Diaza-bicyclo-[3,3,1]-nonanone-( 9)Azabicpclische p-Ketodicarbonsaureester mit Pyridylsubstituenten an C-2 und C-4 (z. B. I-VI) werden in einer Piperidon-RingschluBreaktion durch Umsetzung entsprechend substituierter Piperidonaicarbonsaureester mit Formaldehyd und primaren Aminen erhaltenl) 2).

Bispidine Coordination Chemistry

“…The initial report with metal complexes of tetradentate bispidine ligands dates back to 1969 (31). Following these early reports, there have been a number of studies on the complexation properties of several bipidine derivatives (32)(33)(34)(35).…”

Eccentricities in Spectroscopy and Reactivity of Non‐Heme Metal Intermediates Contained in Bispidine Scaffolds

“…A fused bicyclic skeleton of two piperidine molecules named 3,7-diazabicyclo[3.3.1]nonane, was synthesized for the first time by Mannich [1] in 1930 and was later impregnated by transition metals by Stetter [2] and Haller [3] in 1957 and 1969 respectively. Since then, this molecular scaffold named bispidine, has been subjected to various kinds of studies involving coordination chemistry, [4][5][6][7] diverse organic synthesis, [8][9][10][11] radiopharmaceutical chemistry, [12] and also medicinal chemistry.…”

Optimization of Hexadentate Bispidine Ligands as Chelators for 64CuII PET Imaging

“…As well as undergoing reasonably fast complexation and facile functionalization with biological vectors, ligands of 64 Cu for positron emission tomography (PET) need to yield stable and inert Cu II complexes at nanomolar concentrations under physiological conditions . Among the range of well‐established ligands used in this field, due to the facile synthesis, the large synthetic variability, the ease of derivatization with biological vectors and the relatively high complex stability and inertness, bispidines (3,7‐diazabicyclo[3.3.1]nonanes; see Figure for the bispidine ligands discussed in this manuscript) have been shown to have significant advantages for 64 Cu‐based PET imaging . Among other reasons, these arise from the rigid adamantane‐derived backbone—preorganized and complementary for tetragonally distorted octahedral geometries—that is well suited and selective for binding Cu II ; it is also for this reason that bispidines have been described as a favorable ligand platform for medicinal applications .…”