Antibacterial and antifungal activity of some thiosemicarbazones and 1,3,4-thiadiazolines

Behavior of thiosemicarbazones derived from some terpenones under acetylation conditions. Part II

“…We also found new examples, in addition to those previously described, 4 where we verified the influence of the steric hindrance present in TSC concerning the favored face for TDZ ring closure. In such a sense, we contribute with crystallographic data of two TDZ, 8 and 14, clearly depicting such a situation and reinforcing, even further, our hypothesis regarding the influence of steric hindrance on the diastereoselection found, since again the previous configuration assignment by NMR is corroborated in that the sulphur atom leads to ring closure by attacking from the more hindered face of the molecule.…”

“…In the case of verbenone, besides the effect of the double bond, the existence of the bicyclic bridge with the gem-dimethyl grouping would be expected to influence the course of the reaction, so that it was decided to evaluate the behavior of the dihydro derivative. Accordingly, verbenone (2) was reduced catalytically to verbanone (3) 7 and TSC 7 prepared and treated with acetic anhydride and pyridine 4 to render the corresponding TDZ 8 with very good yield (85 %) and diastereoselectivity. This result would indicate the negative influence of the double bond, more than the steric hindrance of the bicyclic system, in the formation of the heterocycle.…”

“…This type of behavior has been clearly observed in the preparation of the TDZ derivative from some terpenones: mentone, fenchone and camphor. 4 In the present work, these studies of heterocyclization were extended to other TSC derived from other natural terpenones. The aim was to evaluate the presence of an exo and endo conjugated double bond with the imino group, as well as terpenone topography in the stereoselection observed in the end product (TDZ).…”

“…Likewise, TSC were derived from natural terpenones (mentone, fenchone and camphor). 4 Configuration assignment of the new chiral center (C-2 of the heterocycle) was carried out by NMR experiments (2D-NOESY) and in the special case of fenchone by X-ray crystallography. Two possible mechanisms 5 have been proposed for the this heterocyclization reaction, as shown in Scheme 2.…”

Synthesis, Characterization and Antioxidant Activity of Some Transition Metal Complexes With Terpenoid Derivatives

“…Ligands were prepared by method reported earlier. 24,42 Metal contents were measured by complexometric titration 48 . Sulfur was estimated gravimetrically as BaSO 4 and chloride content was determined by Volhard's Methods.…”