Categories: Synthesis of N-Heterocycles, Synthesis of S-Heterocycles >
Synthesis of 1,2,3-thiadiazoles
A facile and practical TBAI-catalyzed reaction between N-tosyl hydrazones
and sulfur provides 1,2,3-thiadiazoles in good yields under metal-free
conditions. This procedure serves as an improvement for the Hurd-Mori reaction.
J. Chen, Y. Jiang, J.-T. Yu, J. Cheng, J. Org. Chem.,
2016,
81, 271-275.
A highly efficient reaction of readily available tosylhydrazones with ammonium thiocyanate
in ecofriendly EtOH as the solvent provides 1,2,3-thiadiazoles in very good
yields at room temperature. The
reaction shows a wide scope of substrates and good functional-group tolerance.
Y. Lu, Y. Sun, A. Abdukader, C. Liu, Synlett, 2021,
32,
1044-1048.
Visible light along with 1 mol % cercosporin catalyzes the synthesis
of 1,2,3-thiadiazoles and 1,4,5,6-tetrahydropyridazines by a photocatalytic
process with good regioselectivity and broad functional-group compatibility
under mild conditions in a sustainable, environmentally friendly manner.
Y. Zhang, Y. Cao, L. Lu, S. Zhang, W. Bao, S. Huang, Y. Rao, J. Org. Chem., 2019, 84,
7711-7721.
The combination of I2 with dimethyl sulfoxide mediates a
cross-coupling cyclization of enaminones, tosylhydrazine, and elemental sulfur
for the synthesis of 5-acyl-1,2,3-thiadiazoles in very good yields under
transition-metal-free conditions. This strategy is operationally simple and
compatible with a wide range of functional groups.
Z. Yang, Y. Liang, A. Li, K. Liu, L. Li, T. Yang, C. Zhou, J. Org. Chem., 2019, 84,
16262-16267.
