Application of N-Acylbenzotriazoles in the Synthesis of 5-Substituted 2-Ethoxy-1,3,4-oxadiazoles as Building Blocks toward 3,5-Disubstituted 1,3,4-Oxadiazol-2(3H)-ones
Sirawit Wet-osot, Wong Phakhodee and Mookda Pattarawarapan*
*Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand, Email: mookdap55gmail.com
S. Wet-osot, W. Phakhodee, M. Pattawarapan, J. Org. Chem., 2017, 82, 9923-9929.
DOI: 10.1021/acs.joc.7b01863 (free Supporting Information)
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A one-pot sequential N-acylation/dehydrative cyclization between ethyl carbazate and N-acylbenzotriazoles in the presence of Ph3P-I2 as a dehydrating agent enables a convenient synthesis of 5-substituted-2-ethoxy-1,3,4-oxadiazoles. Subsequent treatment with a stoichiometric amount of alkyl halides provides 3,5-disubstituted 1,3,4-oxadiazol-2(3H)-ones in very good yields.
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