A facile synthesis of 3‐Substituted 5‐Oxo‐1,2,4‐thiadiazoles from amidoximes |
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Authors: | Yasuhisa Kohara Keiji Kubo Eiko Imamiya Takehiko Naka |
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Abstract: | The reaction of amidoximes 1 with 1,1′‐thiocarbonyldiimidazole (TCDI) followed by treatment with silica gel or boron trifluoride diethyl etherate (BF3·OEt2) provided 3‐substituted 4,5‐dihydro‐5‐oxo‐1,2,4‐thiadiazoles 2 in moderate yields. The Lewis acids are considered to promote the rearrangement of the thioxocarbamate intermediates 5 to the thiol carbarn ate intermediates 7 , which cyclize to afford 4,5‐dihydro‐5‐oxo‐1,2,4‐thiadiazoles 2 . |
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