T. Y. R. Tsai

On cardioactive steroids: The synthesis of γ-isobufalin1

Abstract γ-Isobufalin 1 l was synthesized from testosterone. A novel use of α-furans as masking groups of a carboxylic acid is also reported.

On the stereochemistry of photoaddition between α,β-unsaturated ketones and olefins. III.

The α,β-unsaturated ketone 1 yields with allene the photocycloadduct 3 predicted by our empirical photoaddition rule and the byproduct 7. The formation of this material may be rationalized by the sequence 1 → 4 → 5 → 6 → 7. The isomeric ketone 2 is unreactive under the same conditions, since α addition is prohibited by the rule and β addition is severely blocked.

On cardioactive steroids. IX. The conversion of digitoxigenin to bufalin

A conversion of digitoxigenin I to bufalin 7 via a novel furan-to-pyrone transformation is described. It is hoped that this process will be useful in a simple and efficient total synthesis of bufal...

A simple and efficient synthesis of bufalin

A simple high-yield preparation of bufalin (7) from the steroid (1)(derived from testosterone) by an adaptation of our ‘furan methodology’ for cardenolides is reported.

Conversion of the alkaloid atisine into a compound with the lycoctonine skeleton

The conversion of atisine into the ketone (13), which has a lycoctonine skeleton, and the X-ray structure determination of this product is described.