Synthesis and CYP24A1 inhibitory activity of (E)-2-(2-substituted benzylidene)- and 2-(2-substituted benzyl)-6-methoxy-tetralones

A series of (E)-2-(2-substituted benzylidene)- and 2-(2-substituted benzyl)-6-methoxy-tetralones were prepared, using an efficient synthetic scheme, and evaluated for their inhibitory activity against cytochrome P450C24A1 (CYP24A1) hydroxylase. In general the reduced benzyl tetralones were more active than the parent benzylidene tetralones. The 2-ethyl and 2-trifluoromethyl benzyl tetralone derivatives (4c and 4b) showed optimal activity in this series with IC(50) values of 1 92 mu M and 2.08 mu M, respectively compared with the standard ketoconazole IC(50) 0.52 mu M. The 2-bromobenzyl tetralone (4d) showed a preference for CYP27A1 (IC(50) 59 nM) over CYP24A1 (IC(50) 163 mu M) and may be a useful lead in CYP27A1 inhibition studies The 2-ethylphenyl benzyl derivative (9c), which showed weak activity against the wild type CYP24A1 (IC(50) 25.57 mu M), exhibited enhanced inhibitory activity towards L148F and M416T mutants, this difference in activity for the L148F mutant has been explained using molecular modelling (C) 2010 Elsevier Masson SAS. All rights reserved.