Cyclen phosphine oxide: Hydrogen bonding and transannular N→P interaction

International audienceThe crystal structure of cyclen phosphine oxide demonstrates the existence of an N→P interaction in the crystalline state

Stoichiometric mono N-functionalization of cyclen via a boron protected intermediate

cited By 10International audienceThe temporary triprotection of cyclen by a boron atom performed in presence of sodium hydride offers a convenient solution for the mono N-alkylation of cyclen. Examples of mono N-alkylated cyclens and bis-cyclens are reported. © 2001 Elsevier Science Ltd

Phenylglyoxal for polyamines modification and cyclam synthesis

cited By 12International audienceThe bis-aminals obtained by tetraamine and phenylglyoxal condensation display various behaviours such as equilibrium between different configurations, rearrangements that lead to lactam derivatives, or amine deprotection. Our investigations about them were focused on three different linear amines, and then extended to polyazacycloalkanes cyclen and cyclam. Cyclam was also synthesised with the bis-aminals issued from condensation of linear polyamines with phenylglyoxal. The lactam derivatives described here were moreover, employed for the mono-N-functionalisation of tetraamines by phenyl-acetic acid group. © 2003 Elsevier Science Ltd. All rights reserved

Application of photoelectron spectroscopy to molecular properties. 48. Contribution of photoelectron spectroscopy to the study of the flash vacuum pyrolysis of amino-substituted Meldrum's acid derivatives.

International audienceThe photoelectron spectroscopic study of the thermolysis of amino-substituted Meldrum's acids confirms the formation of several intermediates in the gas phase: their structure depends on the amine function being either secondary or tertiary. In the first case, imidoylketene is clearly characterized, while in the second case, cyclic end-products are identified. In both cases, the electronic structure characterization of unstable methylketene is not obvious from PE data. [on SciFinder(R)

Bis-aminals of linear tetraamines: Kinetic and thermodynamic aspects of the condensation reaction

cited By 22International audienceThe kinetic and thermodynamic aspects of the condensation reaction of dicarbonyl compounds with linear tetraamines were examined in the light of identification of intermediates and DFT calculations. © Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003

Contribution of Photoelectron-Spectroscopy to the Study of the Flash Vacuum Pyrolysis of Amino-Substituted Meldrum Acid-Derivatives

The photoelectron spectroscopic study of the thermolysis of amino-substituted Meldrum's acids confirms the formation of several intermediates in the gas phase: their structure depends on the amine function being either secondary or tertiary. In the first case, imidoylketene is clearly characterized, while in the second case cyclic end-products are identified. In both cases, the electronic structure characterization of unstable methylketene is not obvious from PE data

A convenient synthetic route to polyether-tagged cyclam ligands and their nickel derivatives

International audienceA specific strategy is described for the synthesis of stable polyethylene oxide tagged tetraazamacrocycles (PEO-cyclam) in five steps (overall yields for 12 and 13 48% and 22%, respectively). Various attempts via classical pathways demonstrated: (i) the low reactivity of PEG derivatives, and (ii) the necessity of a stabiliser arm between the cyclam and the PEO chain. Nickel complexes have been prepared and characterised by electrochemistry

A new versatile synthesis of macrotricyclic tetraazacycloalkane-based ligands from bis-aminal derivatives

cited By 30International audienceA new powerful synthesis of symmetrical (two-step) or dissymmetrical (three-step) macrotricyclic cyclen- or cyclam-based ligands is reported. In this procedure, the starting materials are bis-aminals derived from condensation of cyclen or cyclam with glyoxal. The two macrocyclic subunits are linked by two aromatic spacers through nitrogen atoms. © Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003

cis-diprotected cyclams and cyclens: A new route to symmetrically or asymmetrically 1,4-disubstituted tetraazamacrocycles and to asymmetrically tetrasubstituted derivatives

International audienceThe use of cyclam and cyclen oxamides as intermediates for the synthesis of N1,N4-disubstituted tetraazamacrocycles is reported. This pathway affords a general strategy for the preparation of symmetrically or asymmetrically disubstituted derivatives in good yields. Also these intermediates proved convenient synthons for the preparation of asymmetrically tetrasubstituted macrocycles, leading to a new class of potentially dinucleating ligands. © The Royal Society of Chemistry 1999