Oxadiazole
Additional step: convert nitrile to amidoxime by hydroxylamine.
SMARTS: [#6:1][C:2](=[OD1:3])[OH1].[#6:6][C:5]#[#7;D1:4]>>[#6:6][c:5]1[n:4][o:3][c:2]([#6:1])n1
Conditions
Reactant 1: carboxylic acid.
Reactant 2: nitrile.
R1, R2: ar, alkyl.
References
J. K. Augustine, V. Akabote, S. G. Hegde, P. Alagarsamy, J. Org. Chem., 2009, 74, 5640-5643.
Other sources
Organic chemistry