On the partitioning of some newly synthesized mesoionic 1,3,4-thiadiazolium-2-aminide and precursors evaluated by RP-HPLC

Mesoionic thiadiazoliumaminides, known generically as thioisosydnonimines, are antimicrobial drugs. Substitution of lipophilic substituents of mesoion ic ring at 5-position increases their biological potencies against Staphylo ccocus aureus, Staphyloccocus epidermidis, and Bacilus cereus. Mesoionic co mpound, which contains 2,4,Cl2-C6H3- moiety, is the most potent in the seri es. The lipophilicity measurement of log P using RP-HPLC for the newly synt hesized intermediates and mesoionic compounds shows that these compounds ar e quite lipophilic and their behavior towards hydrogen bond capabilities do not allow any differentiation between H-donors, amphiprotics, and H-accept ers.