Iminium Salts of ω-Dithiafulvenylpolyenals: An Easy Entry to the Corresponding Aldehydes and Doubly Proaromatic Nonlinear Optic-phores

A short, high-yielding route to ω-dithiafulvenylpolyenals (1) via the corresponding iminium salts (2) and starting from trimethyl-1,3-dithiolium tetrafluoroborate is reported. The Knoevenagel reactions of either 1 or 2 with isoxazolone-containing acceptors afford merocyanines 7 and 9, in a process that is often accompanied by a vinylene-shortening side reaction. Experimental and theoretical studies reveal that compounds 7 and 9, featuring two proaromatic end groups, are strongly polarized and show good second-order nonlinear optical responses

Improved Flavodoxin Inhibitors with Potential Therapeutic Effects against <i>Helicobacter pylori</i> Infection

<i>Helicobacter pylori</i> (<i>Hp</i>) infection affects one-half of the human population and produces a variety of diseases from peptic ulcer to cancer. Current eradication therapies achieve modest success rates (around 70%), resistance to the antibiotics of choice is on the rise, and vaccination has not proved to be successful yet. Using an essential <i>Hp</i> protein, flavodoxin, as target, we identified three low-molecular-weight flavodoxin inhibitors with bactericidal anti-<i>Hp</i> properties. To improve their therapeutic indexes, we have now identified and tested 123 related compounds. We have first tested similar compounds available. Then we have designed, synthesized, and tested novel variants for affinity to flavodoxin, MIC for <i>Hp</i>, cytotoxicity, and bactericidal effect. Some are novel bactericidal inhibitors with therapeutic indexes of 9, 38 and 12, significantly higher than those of their corresponding leads. Developing novel <i>Hp</i>-specific antibiotics will help fighting <i>Hp</i> resistance and may have the advantage of not generally perturbing the bacterial flora