4,4-Dimethyl-5,8-dihydroanthracene-1,9,10(4H)-trione (Q1) and 9,10-Dihydroxy-4,4-dimethyl-5,8-dihydro-1(4H)-anthracenone (Q2), two molecules that inhibit cancer cell respiration, were selectively deuterated and dissolved in an anionic discotic nematic lyotropic liquid crystal (dnllc) solution. The solution provides a magnetic field oriented anisotropic medium, where the location, average orientation and dynamics of Q1 and Q2 were examined by measuring ²H-NMR quadrupole splittings (AvQ) and ²H longitudinal relaxation times (T1). The NMR data shows that both molecules are strongly attached to the aggregate and, when dissolved, increase the alignment of the interface components with the magnetic field. However they present different average orientations. To assist with the interpretation of the experimental results, 300ns Molecular Dynamics (MD) trajectories of a bilayer model of the aggregate were calculated. The results show that both molecules spontaneously diffuse inside the bilayer, to locate in the limit between the hydrophobic core and the interface. The orientations of both molecules in the aggregate are determined by the formation of H-bonds with water.

Um estudo sistemático das correlações de longo alcance em espectros de HMBC foi feito para uma série de ésteres etílicos do ácido cis- e trans-3-(4-oxo-4H-chromen-3-il) acrílico e os derivados 5-hydroxilados. Os resultados foram comparados com os já observados para espectros IMPEACH-MBC e CIGAR-HMBC. Um acoplamento incomum do tipo 5J C,H entre prótons metilicos e o Ca do grupo carbonilico foi observado nesses sistemas, assim como no crotonato etílico. A atribuição completa dos espectros ¹H e 13C RMN foi realizada.

A systematic study about the long-range correlations observed in the HMBC spectra of a series of cis and trans 3-(4-oxo-4H-chromen-3-yl)-acrylic acid ethyl esters, and 5-hydroxy derivatives, was carried out. The results were compared with those observed in IMPEACH-MBC and CIGARHMBC spectra. An uncommon 5J C,H between the methyl protons and the Ca to the carbonyl group was observed in these systems as well as in ethyl chrotonate. The complete assignments of the ¹H and 13C NMR spectra are provided.

Molecular recognition based on chirality has fundamental importance in many biological processes. Deuterium quadrupole splittings from the aromatic ring and mesophase components of two series of optical isomers, L- and D-N-acyl-1-phenyl-d5-2-aminopropanes, dissolved in anionic nematic cholesteric lyotropic liquid crystals of cesium N-dodecanoyl-L-threoninate, were measured using²H-NMR. The length of the acyl chain was 1, 2, 3, 4, 5, 7 and 10 carbon atoms. The two order parameters that fully characterize the average alignment of the aromatic ring were calculated. Both the L- and D- isomers are strongly attached to the aggregate. L-C1, D-C1, L-C2 and D-C2 derivatives have the same order parameters which suggests that are located in the same region of the interface, possibly H-bonded to the interstitial water molecules with the NH and/or CO groups. Increasing the hydrophobic chain length by one carbon atom decreases the overall alignment of the ring and differences between L-C3 and D-C3 were observed. Molecules with longer acyl chain progressively increase their quadrupole splittings, suggesting an increase in alignment. Increasing differences in the order parameter of the symmetry axis of the aromatic rings in both isomers were observed from C3 to C5, and almost no differentiation is detected between L-C7 and D-C7. However, differentiation appears again for C10, and is attributable to interactions with a second chiral center of the head group

In vitro antimicrobial activity of a series of substituted acetanilides against S. aureus, E. coli and C. albicans were measured at two concentrations, 250 mug/ml and 500 mug/ml. Only the structures substituted with halogens in Calpha and electron acceptors in the aromatic ring are bioactive. The results are rationalized in terms of the acid properties of the N-H bond, as calculated using AM1-MO theory

HOMO and LUMO energies from a 6-31G** full geometry optimization of a series of 7 cyclic hydroxamic acid derivatives were calculated. According to the LUMO energy, the molecules can be classified as hard electrophiles (E LUMO>3.0 eV) and soft electrophiles (E LUMO<2.5 eV). In general, hard electrophiles show a more important biological activity, suggesting that the active site of the biomolecule could be a hard nucleophile. This interpretation is in agreement with the electrophilic character of the hydroxamic function, as suggested by the C=O and O-H stretching frequency of vibration

Se calcularon las energías del HOMO y LUMO a partir de las geometrías optimizadas 6-31 G** de una serie de 7 ácidos hidroxámicos cíclicos. De acuerdo con la energía del LUMO, estas moleculas se pueden clasificar en electrófilos duros (E LUMO>3.0 eV) y electrófilos blandos (E LUMO<2.5 eV). En general, los electrófilos duros muestran una mayor actividad biológica. Esto sugiere que el sitio activo de la biomelécula sería un nucleófilo duro. Esta interpretación está de acuerdo con el carácter electrofílico de la función hidroxámica, como sugieren las frecuencias vibracionales de estiramiento de los enlaces C=O y OH