Nathalie Le Bris

A new route to cyclen, cyclam and homocyclen

Abstract Cyclen, cyclam and homocyclen have been synthesized from the corresponding butanedione-protected linear tetramines. The cyclization step is followed by a facile deprotection of the rigidifying moiety.

Condensation of glyoxal with triethylenetetraamine. Stereochemistry, cyclization and deprotection

Abstract A mixture of bis-aminal isomers was obtained from aqueous glyoxal-triethylenetetraamine condensation. The irreversible isomerization of the species was observed and a new synthesis of cyclen proposed.

Phosphonolipids as non-viral vectors for gene therapy

Several phosphonates with two fatty chains and different polar heads were synthesized and evaluated for their potential to transfer DNA into epithelial (COS-7) and hematopoietic (K562) cell lines, and compared to commercially available references. In both cases, ammonium-phosphonates were particularly efficient.

Cationic phosphonolipids as non viral vectors for DNA transfection

Abstract The Mannich reaction from fatty phosphites followed by quaternarisation of the resulting aminophosphonates led to new cationic phosphonolipids which showed promising DNA transfection properties.

Mono N-functionalization of cyclic and linear tetraamines via their tridentate tricarbonylchromium complexes

The fac-LCr(CO)3 tridentate complexes of 1,4,7,10-tetraazacyclododecane 1, 1,4,8,11-tetraazacyclotetradecane 2, 1,4,7,10-tetraazadecane 3 and 1,5,8,12-tetraazadodecane 4 have been selectively alkylated in high yield at the uncomplexed nitrogen atom, giving rise to mono N-functionalized tetraamines and bis-macrocyclic compounds.

Full control of the regiospecific N-functionalization of C-functionalized cyclam bisaminal derivatives and application to the synthesis of their TETA, TE2A, and CB-TE2A analogues.

We describe an easy synthesis of original C-functionalized cyclam derivatives based on the efficient bisaminal template method. In the perspective of developing bifunctional chelating agents (BCAs), this new synthetic strategy offers the possibility of introducing various coupling functions on one carbon atom in the β-N position of the macrocycle, leaving the four nitrogen atoms available for the introduction of pendant coordinating arms. The methodology is based on a keystone C-functionalized oxo-cyclam bisaminal intermediate that is obtained by cyclization of a preorganized tetraamine using various methyl acrylate analogues. These compounds constitute valuable precursors for selective preparation of mono- and di-N-protected C-functionalized cyclams and C-functionalized cyclams, cross-bridged cyclams, and oxo-cyclam derivatives. This approach was successfully adapted to the synthesis of three BCAs with great interest especially for biomedical applications: TETA, TE2A, and CB-TE2A. The structures of different intermediates and Cu(II) complexes of C-functionalized cyclam derivatives were confirmed using single-crystal X-ray diffraction, while reactivity of the key intermediates was rationalized by the analysis of the electrostatic potentials calculated at the TPSSh/6-311G(d,p) level.

Rhodium-catalyzed hydroformylation of styrene at low temperature using potentially hemilabile phosphite–phosphonate ligands

Abstract The synthesis and the effect of phosphite–phosphonate ligands in rhodium-catalyzed hydroformylation of styrene are described. Activity and selectivity of the catalyst are improved, at low temperature, by increasing bulkiness of both phosphite and phosphonate moieties.

One pot symmetrical and dissymmetrical regiospecific ω,ω′-bis mono N-alkylation of linear tetraamines via their chromium, molybdenum or tungsten tricarbonyl complexes

Abstract Dissymmetric ω, ω′-N-dialkylated linear tetraamines have been obtained after the successive reactions of two aldehydes and subsequent reduction and removal of the M(CO) 3 protection.

Modes of complexation of bis-aminals of linear tetraamines with Group 6 metal carbonyls

Abstract On reaction with Group 6 metal carbonyls M(CO)6, vic type bis-aminals L, issued from the condensation of an α-dicarbonyl compound on a linear tetraamine, give rise to mononuclear cis-M(CO)4L complexes.

Exploring new molecular architectures for anion recognition: synthesis and ATP binding properties of new cyclam-based ditopic polyammonium receptors.

Synthesis and characterization of three new polyamine receptors, composed of a cyclam unit (cyclam=1,4,8,11-tetraazacyclotetradecane) linked by a 2,6-dimethylpyridinyl spacer to the linear polyamines 1,4,8,11-tetraazaundecane (L1py), 1,4,7-triazaheptane (L2py), and to a quaternary ammonium group (L3py(+)), are reported. All receptors form highly charged polyammonium cations at neutral pH, suitable for anion recognition studies. ATP recognition was analyzed by using potentiometric, calorimetric, (1)H and (31)P NMR measurements in aqueous solution. All receptors form 1:1 adducts with ATP in aqueous solution, stabilized by charge-charge and hydrogen-bonding interactions between their ammonium groups and the anionic triphosphate chain of ATP. The binding ability of the three receptors for ATP increases in the order of L3py(+)<L2py<L1py. These adducts are stabilized by largely favourable entropic contributions, probably due to the large desolvation of the host and guest species upon complexation. The sequence observed for the binding affinity is explained in terms of the different ability of the three receptors to wrap around the phosphate chain of ATP.