Mild and convenient one-pot synthesis of 2-amino-1,3,4-oxadiazoles promoted by trimethylsilyl isothiocyanate (TMSNCS)

Substrate‐based synthetic strategies and biological activities of 1,3,4‐oxadiazole: A review

“…Guda et al. (2013) describe a one‐pot synthesis of 2‐amino‐5‐phenyl‐1,3,4‐oxadizole 31 by the reaction between trimethylsilyl isothiocyanate 29 and benzohydrazide 30 undergoes cyclodesulfurization reaction under basic condition in the presence of I 2 /KI gives a final compound 31 with 94% yield (Scheme 9). Reddy et al.…”

Cyclodesulfurization: An Enabling Protocol for Synthesis of Various Heterocycles

“…Synthesis was initiated by the cyclization of N ‐2‐pyridylmethylthioamides 81 via iodine‐mediated oxidative desulfurization along with the presence of pyrimidine as base (Scheme 16A) [70] . Further, Dinneswara and co‐workers reported the synthesis of 2‐amino‐[1,3,4]‐oxadiazole 85 from hydrazide 83 with trimethylsilyl isothiocyanate (TMSNCS) 84 in ethanol under basic condition using I 2 /KI system (Scheme 16B) [71] . The benefit of the process was that no by‐products were generated, thus, avoiding the need for chromatographic purification and the usage of anhydrous solvents.…”

I2 Promoted Synthesis of 2‐Aminothiadiazoles Employing KSCN as a Sulfur Source Under Metal‐Free Conditions

“…Nevertheless, these reported strategies generally require the use of unstable, moisture sensitive, expensive, or hazardous materials, and harsh reaction conditions. In recent years, it is well known that iodine or hypervalent iodide has been widely used in organic synthesis due to its less expensiveness, less toxicity, especially in the synthesis of 1,3,4‐oxadiazoles and 1,3,4‐thiadiazole . For example, Yu reported a synthetic method which can produce both 2‐amino‐1,3,4‐oxadiazole and 2‐amino‐1,3,4‐thiadiazole via the condensation of semicarbazide/thiosemicarbazide with the corresponding aldehydes in the presence of iodine.…”