Synthetic Transformations of Higher Terpenoids. 37. Synthesis and Cytotoxicity of 4-(Oxazol-2-Yl)-18-Norisopimaranes

The synthesis and properties of tricyclic diterpenoids containing a C-4 functionalized oxazole ring are reported. The reaction of 4-[5-(bromomethyl)oxazol-2-yl]-18-norisopimarane with sodium azide in the presence of hydrated copper sulfate and sodium ascorbate in DMF gave the corresponding azide, from which new diterpenoid derivatives containing a 1H-substituted 1,2,3-triazol-4-yl substituent were synthesized. Reduction of the azide produced the...