Structure of the steroidal lactone isolated from turtle bile: (22S,25R)-3α,7α,12α-trihydroxy-5β-cholestano-26,22-lactone

The structure of the steroidal lactone (previously designated as tetrahydroxysterocholanic acid lactone) isolated from the bile of Amyda japonica(turtle) has been characterized as (22S,25R)-3α,7α,12α-trihydroxy-5β-cholestano-26,22-lactone (1). The 22S,25R configuration was determined by 1H n.m.r. comparison with the reference compounds, four possible stereoisomers (with respect to the C-22 and C-25 positions) of 6β-methoxy-3α,5-cyclo-5α-cholestano-26,22-lactones (7)–(10).