Categories: Synthesis of N-Heterocycles, Synthesis of O-Heterocycles >
Synthesis of 1,3,4-oxadiazoles
Recent Literature
A facile and general protocol for the preparation of 2-amino-1,3,4-oxadiazoles
relies on a tosyl chloride/pyridine-mediated cyclization of thiosemicarbazides
that consistently outperforms the analogous semicarbazide cyclizations. Various
5-alkyl- and 5-aryl-2-amino-1,3,4-oxadiazoles have been prepared in good yields.
S. J. Dolman, F. Gosselin, P. D. O'Shea, I. W. Davies, J. Org. Chem., 2006,
71, 9548-9551.
Symmetric and unsymmetric 1,3,4-oxadiazoles were synthesized in situ from
hydrazine hydrate and the corresponding 2-acyl-4,5-dichloropyridazin-3-ones
as acylating agents in polyphosphoric acid (PPA) or BF3ˇOEt2
in excellent yields.
Y.-D. Park, J.-J. Kim, H.-A. Chung, D.-H. Kweon, S.-D. Cho, S.-G. Lee, Y.-J.
Yoon, Synthesis, 2003, 560-564.
