Thiazoles and their derivatives is an important class of biologically active compounds, widespread in nature
(e.g. alkaloids)or prepared synthetically (e.g. pharmaceuticals)1. The results of investigations devoted to the
synthesis of new trinorlabdane compounds containing thiazole structural units are reported.
The key strengths of this research are: accessible starting material, which is commercially available
sclareolide 1, obtained from natural labdane diterpenoide (-)-sclareol,extracted from renewable resources and high
probability of biological activities and low toxicity of the title compounds, due to their natural origin. The target
trinorlabdanederivatives 7 and 8 containingthiazole units were prepared by interaction of intermediate
thiosemicarbazones5 and 6 with 2-bromoacetophenone under depicted conditions2. In turn, the thiosemicarbazones5
and 6, were prepared from sclareolide 1, in 3 steps3(Scheme).

Reagents: a. CH3Li/Et2O, 65%; b.CH3SO2OSiMe3, MeCN,80% (in 80:20 ratio);
c. NH2NHCSNH2 or NH2NHCSNHC6H5, EtOH, 71-85%; d. C6H5COCH2Br, EtOH, 75-83%.
Scheme
The structure of all synthetized compounds have been established using modern methods of analysis (1H, 13C
and 15N NMR and MS spectrometry).
Acknowledgements: The financially support from the STCU (Ukraine) Project No 6330 is acknowledged.
References:
1. L. M.T. Frija., A. J.L. Pombeiro., M. N. Kopylovich.J.Coord. Chem. Reviews,2016, 308, 32–55.
2. R.M. Mohareb, W.W. Wardakhan, G.A. Elmegeed, R.M.S. Ashouret.Steroids, 2012, 77, 1560-1569.
3. K.I. Kuchkova,Yu.M. Chumakov, G. Bocelli, A.A. Panasenko, P.F. Vlad. Synthesis, 1997, 9, 1045-1049.