Synthesis and plant growth promoting activity of dinorcholanic lactones bearing the 5α-hydroxy-6-oxo moiety.

The naturally occurring dinorcholanic lactone vespertilin and two other non-natural derivatives bearing the 5α-hydroxy-6-oxo moiety were synthesized starting from the readily available steroid sapogenin diosgenin. The obtained compounds showed plant growth promoting activity in the bean's second internode elongation assay.