The reaction of polyhydrazides with phosphorus pentasulfide in pyridine has yielded polyoxathiahydrazides, polydithiahydrazides, and poly‐1,3,4‐thiadiazoles. At 115°C. after 30 min. of reaction time the major product was polyoxathiahydrazide; after 24 to 48 hr. the major product was polydithiahydrazide; after 120 hr. the major product was poly‐1,3,4‐thiadiazole. 3‐Picoline and pyridine were the preferred reaction media; other picolines, lutidine, piperidine, quinoline, dimethylacetamide, and o‐dichlorobenzene were not useful. Characterization of the polymeric products was accomplished by a combination of thermal and spectroscopic analyses. Ultraviolet absorption spectra, relative fluorescence of long‐wavelength ultraviolet light, thermogravimetric analysis, differential thermal analysis, and characteristic absorption bands in the infrared were all used to elucidate structure. This reaction has been found to be general for polyhydrazides. All‐aromatic, aromatic‐aliphatic, aromatic‐heterocyclic, and aromatic‐oxalic hydrazides have yielded the corresponding polyoxathiahydrazides, polydithiahydrazides, and poly‐1,3,4‐thiadiazoles.
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Frazer et al. (1968) studied this question.