- Synthesis of a series of N6-substituted adenosines with activity against trypanosomatid parasites
-
The involvement of purine salvage in the accumulation of current trypanocidal drugs is important for the treatment of African sleeping sickness. The substrate specificity of essential nucleoside transporters is therefore of physiological and pharmacological interest. With the intention to contribute to the knowledge in the field, a series of 16 adenosine derivatives with substituents in N6-position were prepared in order to evaluate their potential to inhibit Trypanosoma brucei spp. in vitro. An unmodified ribose moiety was selected to conserve key molecular recognition motifs of the arsenal of integral membrane proteins expressed in large numbers on the protozoan plasma membrane. Two of the new compounds prepared using a polymer-assisted acylation protocol showed antitrypanosomal activities in the single digit micromolar concentration range.
- Link, Andreas,Heidler, Philipp,Kaiser, Marcel,Brun, Reto
-
experimental part
p. 3665 - 3671
(2009/12/04)
-
- Design and synthesis of macrocyclic ligands for specific interaction with crystalline ettringite and demonstration of a viable mechanism for the setting of cement
-
Cementitious materials are among those most widely used by mankind while being among the least well understood. The detailed physicochemical processes involved in the hydration and setting of cement slurries are very complex, and a clearly defined quantitative account is still lacking: indeed, even the composition of the cement powder itself is not known exactly. Still less has there been any understanding of the mechanism by which numerous known retarders of the cement setting process act. In this article, we detail the synthesis of novel macrocyclic organophosphonate retarders 1a and 2a which were developed by rational methods. Attempts to synthesise these compounds as phosphonate ester derivatives were universally unsuccessful, however direct modification of the parent hexaaza-(3) and trioxatriaza-18-crown-6 (5) derivatives was successful, to provide the phosphonic acids 1b and 2b respectively. Subsequent testing of these compounds showed their ability to inhibit the growth of crystalline ettringite and delay the setting of cement. These results support the hypothesis that the formation of crystalline ettringite is the rate determining step in the setting of cement.
- Griffin, Jonathan L. W.,Coveney, Peter V.,Whiting, Andrew,Davey, Roger
-
p. 1973 - 1981
(2007/10/03)
-
- Conformational Studies on Model Compounds of Polyamides with Ether Groups in Their Structure
-
The synthesis of 1,5-dibenzamido-3-oxapentane (DEBA) and 1,8-dibenzamido-3,6-dioxaoctane (TEBA), model compounds of polyamides with repeating units and , respectively, is reported.The mean-square dipole moment, 2>, of both compounds was measured in dioxane solutions in the interval of temperatures 30-60 deg C.The values of this quantity lie in the ranges 24.6-24.5 D2 and 25.4-26.0 D2, for DEBA and TEBA, respectively.The analysis of the spectral patterns of the model compounds indicates that the energy E?' of gauche states about the CH2-CH2 bonds adjacent to the amide groups is 0.44+/-0.08 kcal mol-1 below that of the alternative trans states.Moreover, semiempirical calculations show that gauche states about NH-CH2 bonds are also preferred over the alternative trans, in contrast with CH2-O bonds in polyesters, where the opposite occurs.The critical interpretation of the dipole moments of both DEBA and TEBA by the rotational isomeric state (RIS) model suggests that their polarities are very sensitive to the modulus of the dipole moments associated with the amide groups, but they are nearly insensitive to their orientation.Calculations of the dipolar distribution and the corresponding average energies carried out for DEBA and TEBA suggest that the conformers of higher polarity also have the highest energy.
- Abajo, J. de,Campa, J. G. de la,Riande, E.,Garcia, J. M.,Jimeno, M. L.
-
p. 8669 - 8674
(2007/10/02)
-