The 1,3,4-thiadiazole and its derivatives are considered interesting heterocycles since they possess
important pharmacological activities1. The results of investigations devoted to a simple and
environmentally friendly, one step procedure for the synthesis of new title compounds are reported. The
tetranorlabdanederivatives 3a-c bearingthiadiazole units were prepared by treating hydrazide 2 with
substituted isothiocyanates in water and in the presence of triethylamine. The hydrazide2in turn, was
prepared from commercially available sclareolide 1 according to Scheme.

The antimicrobial and antifungal activities of the compounds 3a-c were assessed by performing “in
vitro” tests against five species of fungi (Aspergillus niger, A. flavus, Penicillium chrysogenum, P.
frequentans, Alternaria alternata)and two species of bacteria (Pseudomonas aeroginosa and Bacillus
sp.).2Compound 3a showed a good antifungal activity, at the MIC of 0.25 μg/mL in comparison with the
reference compound Caspofungin(MIC = 0.21 μg/mL),and antibacterial activity, atthe MIC of 0.5 μg/mL
in comparison with the reference compound Kanamycin (MIC = 3.2 μg/mL).
The structures of compounds 3a-c were fully confirmed based on their 1H, 13C and 2D NMR data.
Acknowledgements: The financially support from the STCU (Ukraine)Project No 6330 is acknowledged.

References:
[1]. Hu Y. et al. 1,3,4-Thiadiazole: Synthesis, Reactions, and Applications in Medicinal, Agricultural, and Materials
Chemistry. Chemical Reviews, 2014, 114, p. 5572-5610.
[2]. National Committee on Clinical Laboratory Standards (NCCLS), “Antimicrobial Susceptibility Standards (ATS)”, ed.
2003, for M7 (CMI) and M100.