A Novel Chemo‐selective Epoxidation across Acrylate Ester: Synthesis of New Water‐Soluble Forskolin Analogues

Abstract

While removing the TBDMS group from OH protection, a novel epoxidation reaction occurred across acrylate ester attached to a forskolin fragment. Besides spectroscopic data, the epoxide formation was confirmed by ring opening with a secondary amine. This unique epoxidation reaction, to our knowledge, is not known in the literature. This reaction led us to discover a simple deblocking protocol. The epoxide and the desired Michael substrates were used to introduce imidazole into forskolin.

Keywords:

• Epoxidation reaction
• forskolin analogues
• regiospecific simple deblocking protocol

Acknowledgements

We gratefully acknowledge R. H. Rupp for his interest and encouragement. We also acknowledge the late A. N. Dohadwalla and N. K. Dadkar for their help in pharmacological screening, P. K. Inamdar and his group for analytical data, and A. Ranade for providing valuable literature information.