To tackle the loss of activity of surfaces functionalized by coating and covalently bound molecules to materials, an intermediate system implying the noncovalent immobilization of active molecules in the inner cavity of grafted cyclodextrins (CDs) was investigated. The antifungal and antibiofilm activities of the most stable complexes of Anidulafungin (ANF; echinocandin) and thymol (THY; terpen) in various CDs were demonstrated to be almost the same as the free molecules. The selected CD was covalently bond to self-assembled monolayers on gold surfaces. The immobilized antifungal agents reduced the number of culturable Candida albicans ATCC 3153 attached to the surface by 64 ± 8% for ANF and 75 ± 15% for THY. The inhibitory activity was persistent for THY-loaded samples, whereas it was completely lost for ANF-loaded surfaces after one use. However, reloading of the echinocandin restored the activity. Using fluorescent dying and confocal microscopy, it was proposed that the ANF-loaded surfaces inhibited the adherence of the yeasts, whereas the activity of immobilized THY was found fungicidal. This kind of tailored approach for functionalizing surfaces that could allow a progressive release of ANF or THY gave promising results but still needs to be improved to display a full activity.

Nucleophilic substitution of 2beta-mesyloxymethyl-N-methyl-3beta-p-tolyl-tropane intermediate with alkoxides, metal imides, or amines was found to lead not only to the expected bicyclo[3.2.1]octane (tropane) ether, imide, and amine derivatives but also to unexpected bicyclo[3.2.2]nonane derivatives. When alkoxides were used as nucleophile, only the rearranged bicyclo[3.2.2]nonane structure was obtained, whereas the use of amines or imides as nucleophile afforded a mixture of the two structures. The bicyclo[3.2.2]nonane structure was assigned by NMR analysis.

International audienceIn order to visualize and quantify dopamine transporters, the synthesis of two novel ligands labelled with technetium-99 m (99mTc) has been investigated. A multi-step synthesis afforded two target ligands with a tropane skeleton and a macrocyclic complexing moiety. The choice and the position of substituents are in adequation with dopamine transporter structure. The radiolabelling of these ligands with 99mTc has been studied and the results make them good candidates for SPECT imaging

The synthesis of eleven new cyclodextrin derivatives having nucleobase moiety -thymin-1-yl, adenin-9-yl, and guanin-9-yl -is described. These two moieties are linked by different spacers, such as aminoethyl and 1,2,3-triazolyl group. Direct nucleophilic substitution and 1,3-dipolar cycloaddition were performed in good yields (13-73%) for some of the synthesized compounds. Cyclodextrins (CDs) are versatile macrocyclic maltooligosaccharides composed of a-(1→4)-linked D-glucopyranose units in 4 C 1 chair conformation and are produced from starch by enzymatic conversion in nature. The most common CDs have six, seven, and eight D-glucopyranose units and are referred to as a-, b-, and g-CD, respectively. In the case of b-CD, the polyhydroxylated compound has got a primary face of 7 hydroxy groups and a secondary face of 14 hydroxy groups. As a consequence of the structure, the molecule is hydrophilic and features a conical cavity that is essentially hydrophobic in nature. It is well known that CDs can form inclusion complexes with a variety of guest molecules due to its unique hydrophobic cup-like structure. Among these properties, the ability to form drug carrier, 1-3 separation reagents, 4-6 enzyme mimics, 7,8 photochemical sensors, 9,10 catalysis, 11,12 host-guest interactions, 13 and molecular recognition 14 are probably the most commercially valuable. Compared to CD monomers, the bridged bis(b-CD) derivatives with functional linkers have two hydrophobic cavities in a close proximity constituting an improved development. 15 This property may afford distinctly different association abilities and molecular selectivities. 16 Various structural architectures of covalent CD dimers could be prepared, but one challenge will be to obtain supramolecular CD dimers with noncovalent interactions such as H bonding, staking, electrostatic, and charge-transfer interactions. The equilibrium between the noncovalent dimers and the corresponding monomers could permit modulation of association. To the best of our knowledge, these molecular organization behaviors have not been extensively investigated. 17 The supramolecular assembly could be obtained by association of nucleobases such as adenine and thymine or guanine and cytosine. Few examples of CD derivatives having nucleobase were described in the literature, but only the study of CD monomers were reported. 18-23 As previously reported by Len's group, 18 the apparent association constant between two nucleobases appended permethylated cyclodextrin derivatives was determined by NMR in CDCl 3 . The self-assembly property of CD derivatives 13b and 14b was K TT = 22 M -1 and K AA = 16 M -1 respectively. The association constant for heterodimerization of 13b and 14b in a 1:1 stoichiometry was K AT = 385 M -1 supporting the formation of supramolecular heterodimer of modified cyclodextrins. The presence of bulky CDs did not perturb the interactions between nucleobases. In this paper, we report our contribution regarding the synthesis of different CD monomers having a nucleobase such as ad...

The synthesis of six new cyclodextrin derivatives having nucleobase moiety is described. These two moieties are linked by different spacers, such as aminoethyl and 1,2,3-triazolyl groups. Example of association constants for complexation of adenine and thymine derivatives: K AT = 385 M -1 using NMR methodology is reported. Study of interaction between four cyclodextrin derivatives and one adamantyl guest is described by ITC.Cyclodextrins (CD) are a family of cyclic oligosaccharides composed of a-(1→4)-linked D-glucopyranose units in 4 C 1 chair conformation. The most common CD have six, seven, and eight glucopyranose units and are referred to as a-, b-, and g-CD, respectively. As a consequence of the structure, the molecule is hydrophilic and features a conical cavity that is essentially hydrophobic in nature. This property enables them to be successfully used as drug carrier, 1-3 separation reagents, 4-6 enzyme mimics, 7,8 photochemical sensors, 9,10 catalysis, 11,12 host-guest interactions, 13 and molecular recognition. 14 In comparison with CD monomers, CD dimers tethered by a spacer of different sizes and shapes have two hydrophobic cavities in a close vicinity. 15 This property may afford distinctly different apparent association abilities and molecular selectivities. 16 Various structural architectures of covalent CD dimers could be prepared but one challenge will be to obtain supramolecular CD dimers with noncovalent interactions such as H bonding, staking, electrostatic, and charge-transfer interactions. The equilibrium between the noncovalent dimers and the corresponding monomers could permit to modulate the association. Unexpectedly, these molecular organization behaviors have not been extensively investigated. The supramolecular assembly could be obtained by association of nucleobases such as adenine and thymine or guanine and cytosine. Few examples of CD derivative having nucleobase were described in the literature but only the study of CD monomers were reported. [17][18][19][20][21] In this paper, we reported our preliminary work regarding the synthesis of different CD monomers having a nucleobase such as adenine and thymine and their potential application for the formation of supramolecular CD dimers. The target compounds 8, 9, 11, and 12 had three major structural variations and were novel CD derivatives. First modulation was the glycone moiety: amino-b-CD, azido-b-CD, or amino-permethylated b-CD derivatives. Second variation was the nature of the linker: aminoethyl group or 1,2,3-triazol-4-ylmethyl group. Third modulation was the nucleobase: adenine or thymine.N-Alkylation of pyrimidine bases gave predominantly N1-monosubstituted and N1,N3-bis-substituted derivatives. In order to prepare regioselectively the N1-alkylated pyrimidine, silylation of the nucleobase was developed. Coupling of dibromoethane with silylated thymine (1) in presence of NaI at 105°C without solvent furnished the bromide 2 22-25 in 32% yield. Coupling of propargyl bromide with silylated thymine at 80°C in acetonitrile gave t...