Amino acids U 0400 N-Sulfonyl Homoserine Lactones as Antagonists of Bacterial Quorum Sensing. -The synthesis of new analogues of N-acylhomoserine lactones such as (V) and (VI) (11 examples in all) in which the carboxamide function is replaced by a sulfonamide, and their evaluation as antagonists of bacterial quorum sensing are described. Several compounds, especially compounds (Va) and (Vc), display antagonistic activity. -(CASTANG, S.; CHANTEGREL, B.; DESHAYES, C.; DOLMAZON, R.; GOUET, P.; HASER, R.; REVERCHON, S.; NASSER, W.; HUGOUVIEUX-COTTE-PATTAT, N.; DOUTHEAU*, A.; Bioorg. Med. Chem. Lett. 14 (2004) 20, 5145-5149; Lab. Chim. Org., Dep. Biochim., Inst. Natl. Sci. Appl., F-69621 Villeurbanne, Fr.; Eng.) -M. Schroeter 05-177

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The low-temperature mechanical relaxations in poly(oxy-1,4-phenyleneoxy-1,4-phenylenecarbonyl-1,4-phenylene [poly(aryl ether ether ketone, PEEK], poly(thio-1,4-phenylene) [poly(phenylene sulfide), PPS], and poly(oxy-1,4-phenylenesulfonyl-1,4-phenylene), [poly(aryl ether sulfone), PES] are investigated. All three polymers exhibit a low-temperature γ relaxation, in the temperature range from 40 to 100 K at 1 Hz. The apparent activation energies for the γ relaxations (15−25 kJ/mol) are close to the values derived from empirical force field molecular mechanics calculations of the “crankshaft motion” in an isolated chain portion. Only polymers with a polar interaromatic bridge (PEEK and PES) exhibit another secondary β relaxation, in the temperature range from 100 to 250 K at 1 Hz. Moreover, the apparent activation energies of the β processes are significantly higher than the activation energies of the γ relaxations. Therefore, it is concluded that polar intermolecular interactions play an important role in the molecular events leading to the β relaxation, whereas the γ relaxation is due to conformational changes mostly controlled by an intramolecular energy.

The dichloromethane extract of Ferula hermonis roots, isolated in 26.5% yield based on dry roots, contained as principal components p-hydroxybenzoate (1b) and benzoate (1a) of jaeschkeanadiol (52% and 30%, respectively). Some other aryl esters of jaeschkeanadiol and 2,3-epoxide jaeschkeanadiol, as well as˛-bisabolol, were present in small amounts.