Ethyl thionoacetate

Reaction of diazoalkanes with thiocarbonyl compounds, which may be considered an extension of Pechmann s synthesis, forms 1,2,3-thiadiazole derivatives (75SST(3)67o). For example, methyl dithioacetate reacts with diazomethane to form a mixture of thiadiazole isomers and thiirane the latter often is the main product of this type of reaction (equation 26). O-Ethyl thionoacetate reacts with ethyl diazoacetate to form a substituted thiadiazole (equation 27). However, an aryl thionoester reacts with diazomethane to yield a 1,2,3-thiadiazole derivative which is only formed as an intermediate (31) and then rapidly decomposes to alkene (Scheme 5). 

From Hydrazones.—Raap and Micetich s synthesis of 1,2,3-thiadiazoles [from (12)] has been applied to the production of further examples (13). The use of the readily accessible hydrazone (14) provides the desired compounds directly in one step. The condensation of diazoacetate with 0-ethyl thionoacetate affords the substituted 1,2,3-thiadiazole (15). ... 

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