Novel and Efficient Cyclization Procedure for the Synthesis of 2,5-Disubstituted-1,3,4-thiadiazoles Without Using Any Ring-Closing Reagents
摘要:
A novel method for the synthesis of 2,5-disubstituted-1,3,4-thiadiazoles via direct ring closure of 1,6-disubstituted-2,5-dithioureas in dimethylformanide without using any ring-closing reagents has been accidentally discovered. Repeated and extended experiments confirmed that this is a very simple and efficient way to synthesize these kinds of fine chemicals. A series of novel 2,5-disubstituted-1,3,4-thiadiazoles have been synthesized via this method in good yields.
Phase Transfer Catalyzed Synthesis of 1,6-Diaroyldithiohydrazodicarbonamide Derivatives
摘要:
Reaction of hydrazine hydrate with aroyl chloride and ammonium thiocyanate under the condition of solid-liquid phase transfer catalysis using polyethylene glycol-600 (PEG-600) as the catalyst yielded 1,6-diaroyldithiohydrazodicarbonamides 3a - 3h in good to excellent yield.