Polyfluoro-2,3-epoxyalkanes in reactions with thiourea and thiosemicarbazide

Reactions of polyfluoro-2,3-epoxyalkanes with thiourea and thiosemicarbazid e afforded 2-amino-4-hydroxy-4,5-di(polyfluoroalkyl)-5-fluoro-1,3-thiazolin es and 2-hydrazino-4-hydroxy-4,5-di(polyfluoroalkyl)-5-fluoro-1,3-thiazolin es respectively. Unsymmetrical oxiranes furnish mixtures of regioisomeric h eterocyclic compounds, and the epoxy cycle is predominantly cleaved from th e side of bulkier fluoroalkyl group. The reactions of E-oxiranes are stereo specific and provide 1,3-thiazolines in the E-form. The structure of compou nds obtained was confirmed by IR, F-19, H-1, and C-13 NMR spectroscopy, by mass spectra and chemical transformations. E-isomers of 2-amino-4-hydroxy-4 ,5-bis(trifluoromethyl)-5-fluoro-1,3-thiazoline and 2-amino-5-heptafluoropr opyl-4-hydroxy-4-trifluoromethyl-5-fluoro-1,3-thiazoline were subjected to X-ray diffraction analysis.