Synthesis, spectroscopy, and theoretical calculations of some 2-thiohydantoin derivatives as possible new fungicides.

We present the synthesis and structure determination for two thiohydantoin compounds (5-benzylidene-2-sulfanylideneimidazolidin-4-one and 5-cinnamylidene-2-sulfanylideneimidazolidin-4-one), proposed as potential novel fungicides. The exact chemical structure of these molecules has not yet been determined since they can potentially exist in several tautomeric and geometric forms (Z-E isomerism). The geometries of all the theoretically possible structures of the studied compounds were optimised. The calculations were performed at the density functional theory level using the B3LYP functional and the 6-311++G** basis set. Based on our calculations, the most probable structures of the studied compounds were proposed. The theoretical predictions were verified by comparing the calculated IR as well as the