Table 3 Relationship between chemical features and potency of the nine active compounds.
Chemical features | Order of potency | ||||||||
|---|---|---|---|---|---|---|---|---|---|
4 | >5 | >>8* | >20 | >21 | >7* | >6* | >9* | >>13 | |
=CO (C6) | + | + | − | + | + | + | − | − | − |
–OH (C6) | − | − | + | − | − | − | + | + | − |
=bond at C1 | + | + | − | + | + | − | + | − | − |
Michael centre | + | + | − | + | + | − | − | − | + |
Michael centre sterically hindered | No | No | − | No | No | − | − | − | Yes |
Isopropenyl group at C4 | Yes | Yes | Yes | No | No | Yes | Yes | Yes | No |
Chirality at C4 | S | R | S | S | R | R | R | R | − |
Chirality at C1 | − | − | S | − | − | S/R | − | R | S |
Chirality at C6 | − | − | S | − | − | − | S/R | R | − |
