Chemical structure of the catalysts evaluated in this study. HOBt: 1-hydroxybenzotriazole, 6-Cl-HOBt: 6-chloro-1-hydroxybenzotriazole, 6-CF 3 -HOBt: 1-hydroxy-6-(trifluoromethyl)benzotriazole, HOAt: 3-hydroxytriazolo[4,5-b]pyridine, HOCt: ethyl 1-hydroxytriazole-4-carboxylate, Oxyma Pure: ethyl (2E)-2-cyano-2-hydroxyiminoacetate.
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