Benzo- and cyclohexanomazindol analogues as potential inhibitors of the cocaine binding site at the dopamine transporter.

A series of mazindol (1), homomazindol (2), and bishomomazindol (3) derivatives with a benzo or cyclohexano ring fused at various sites were prepared as part of an SAR study to determine the effect of increased aliphatic and aromatic lipophilicity on selected in vitro assays used to identify potential cocaine-like and cocaine antagonism activity. Very good (IC(50) = 2-3 nM) inhibition of [(3)H] WIN 35,428 and [(125)I] RTI-55 binding on rat or guinea pig striatal membranes and HEK cells expressing cDNA for the human dopamine transporter (HEK-hDAT) was shown by the 8,9-benzomazindol 25 and 9,10-benzohomomazindol 28. All new compounds were weaker inhibitors of [(3)H] DA uptake in HEK-hDAT cells than 1 and 2.

Mazindol analogues as potential inhibitors of the cocaine binding site at the dopamine transporter.

A series of mazindol (2) and homomazindol (3) analogues with a variety of electron-donating and electron-withdrawing groups in the pendant aryl group and the benzo ring C, as well as H, methoxy, and alkyl groups replacing the hydroxyl group were synthesized, and their binding affinities at the dopamine transporter (DAT) on rat or guinea pig striatal membranes were determined. Several active analogues were also evaluated for their ability to block uptake of DA, 5-HT, and NE and inhibit binding of [(125)I] RTI-55 at HEK-hDAT, HEK-hSERT, and HEK-hNET cells. Mazindane (26) was found to be a pro-drug, oxidizing (5-H --> 5-OH) to mazindol on rat striatal membranes and HEK-hDAT cells.

Triterpene and diterpene inhibitors of pyruvate dehydrogenase kinase (PDK).

Several oximes of triterpenes with a 17-beta hydroxyl and abietane derivatives are inhibitors of pyruvate dehydrogenase kinase (PDK) activity. The oxime 12 and dehydroabietyl amine 2 exhibit a blood glucose lowering effect in the diabetic ob/ob mouse after a single oral dose of 100 micromol/kg. However, the mechanism of the blood glucose lowering effect is likely unrelated to PDK inhibition.