Discovery of a Potent, Long-Acting, and CNS-Active Inhibitor (BIA 10-2474) of Fatty Acid Amide Hydrolase.

Fatty acid amide hydrolase (FAAH) can be targeted for the treatment of pain associated with various medical conditions. Herein we report the design and synthesis of a novel series of heterocyclic-N-carboxamide FAAH inhibitors that have a good alignment of potency, metabolic stability and selectivity for FAAH over monoacylglycerol lipase (MAGL) and carboxylesterases (CEs). Lead optimization efforts carried out with benzotriazolyl- and imidazolyl-N-carboxamide series led to the discovery of clinical candidate 8 l (3-(1-(cyclohexyl(methyl)carbamoyl)-1H-imidazol-4-yl)pyridine 1-oxide; BIA 10-2474) as a potent and long-acting inhibitor of FAAH. However, during a Phase I clinical trial with compound 8 l, unexpected and unpredictable serious neurological adverse events occurred, affecting five healthy volunteers, including the death of one subject.

Discovery of a long-acting, peripherally selective inhibitor of catechol-O-methyltransferase.

Novel nitrocatechol-substituted heterocycles were designed and evaluated for their ability to inhibit catechol-O-methyltransferase (COMT). Replacement of the pyrazole core of the initial hit 4 with a 1,2,4-oxadiazole ring resulted in a series of compounds endowed with longer duration of COMT inhibition. Incorporation of a pyridine N-oxide residue at position 3 of the 1,2,4-oxadiazole ring led to analogue 37f, which was found to possess activity comparable to entacapone and lower toxicity in comparison to tolcapone. Lead structure 37f was systematically modified in order to improve selectivity and duration of COMT inhibition as well as to minimize toxicity. Oxadiazole 37d (2,5-dichloro-3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-4,6-dimethylpyridine 1-oxide (BIA 9-1067)) was identified as a long-acting, purely peripheral inhibitor, which is currently under clinical evaluation as an adjunct to L-Dopa therapy of Parkinson's disease.

Efficient synthesis of 2-(trifluoromethyl)nicotinic acid derivatives from simple fluorinated precursors.

Novel routes to 2-trifluoromethyl-nicotinic acid derivatives have been developed involving synthesis of the pyridine ring. These pyridyl compounds serve as key intermediates in the manufacture of the recently discovered COMT inhibitor, 3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-oxadiazol-3-yl)-2-(trifluoromethyl)pyridine 1-oxide.