A series of 3-aryl-3-arylmethoxy-azetidines were synthesized and evaluated for binding affinities at dopamine and serotonin transporters. The 3-aryl-3-arylmethoxyazetidines were generally SERT selective with the dichloro substituted congener 7c (Ki = 1.0 nM) and the tetrachloro substituted derivative 7i (Ki = 1.3 nM) possessing low nanomolar affinity for the SERT. The 3-(3,4-dichlorophenyl-3-phenylmethoxyazetidine (7g) exhibited moderate affinity at both DAT and SERT transporters and suggests that substitution of the aryl rings can be used to tune the mononamine transporter affinity.

A series of benzyl esters of meperidine and normeperidine were synthesized and evaluated for binding affinity at serotonin, dopamine and norepinephrine transporters. The 4-methoxybenzyl ester 8b and 4-nitrobenzyl ester 8c in the meperidine series and 4-methoxybenzyl ester 14a in the normeperidine series exhibited low nanomolar binding affinities at the SERT (Ki values <2 nM) and high SERT selectivity (DAT/SERT >1500 and NET/SERT >1500).

Both the R and S enantiomers of the amphibian alkaloid noranabasamine were prepared in >30% overall yield with 80% ee and 86% ee, respectively. An enantioselective iridium-catalyzed N-heterocyclization reaction with either (R)- or (S)-1-phenylethylamine and 1-(5-methoxypyridin-3-yl)-1,5-pentanediol was employed to generate the 2-(pyridin-3-yl)-piperidine ring system in 69−72% yield.

A short multigram process for the preparation of the analgesic compound SCP-123 (4) and its sodium salt has been developed.

A series of 3-arylnortrop-2-enes and 3α-arylmethoxy-3β-arylnortropanes were synthesized and evaluated for binding affinity at monoamine transporters. The 3-(3,4-dichlorophenyl)nortrop-2-ene (6e) exhibited high affinity for the SERT (Ki = 0.3 nM). The 3α-arylmethoxy-3β-arylnortropanes were generally SERT selective with the 3α-(3.4-dichlorophenylmethoxy)-3βphenylnortrop-2-ene (7c) possessing subnanomolar potency (Ki = 0.061 nM). However, 3α-(3,4-dichlorophenylmethoxy)-3β-phenylnortrop-2-ene (7b) exhibited high affinity at all three transporters [(DAT Ki = 22 nM), (SERT Ki = 6 nM) and (NET Ki = 101 nM)].The design, synthesis and monoamine transporter affinity of a series of nortropane derivatives is described.

A series of 4-alkoxycarbonyl-1,5-diaryl-1,2,3-triazoles were synthesized regioselectively using click chemistry and evaluated at CB1 cannabinoid receptors. The n-propyl ester 11 (Ki = 4.6 nM) and phenyl ester 14 (Ki = 11 nM) exhibited the most potent affinity of the series.A series of 4-alkoxycarbonyl-1,5-diaryl-1,2,3-triazoles were synthesized regioselectively using click chemistry and evaluated at CB1 cannabinoid receptors. The n-propyl ester (Ki = 4.6 nM) exhibited the most potent affinity of the series.

The structure–activity relationships of 3′,4′-dichloro-meperidine were investigated at dopamine (DAT) and serotonin transporters (SERT). Large ester substituents and lipophilic groups at the 4-position favored molecular recognition at the SERT. The benzyl ester of 3′,4′-dichloro-meperidine exhibited high potency and high selectivity for the SERT (DAT/SERT = 760). Chemical modification of the ester group and N-substitution generally led to compounds with decreased DAT affinity. Only small esters and alkyl groups were tolerated at the 4-position of the meperidine ring system by the DAT. Overall, the meperidine analogues were generally more selective for the SERT than for the DAT.

A novel and practical procedure for preparation of imides is described using chromium(VI) oxide to catalyze the oxidation of N-alkylamides with periodic acid in the presence of acetic anhydride in acetonitrile.

A series of epiboxidine homologues, 2- and 3-isoxazole substituted 8-azabicyclo[3.2.1]octane derivatives was synthesized and evaluated as potential ligands for neuronal nicotinic acetylcholine receptors in [3H]cytisine labeled rat brain. The 2β-isoxazolyl-8-azabicyclo[3.2.1]octane 9b (Ki=3 nM) was the most potent compound of the series with a binding affinity twice that of nicotine. The 3β-isoxazolyl-8-azabicyclo[3.2.1]octane 15b (Ki=148 nM) exhibited moderate affinity while the corresponding 2α- and 3α-isomers exhibited micromolar binding affinity.A series of epiboxidine homologues, 2- and 3-isoxazole substituted 8-azabicyclo[3.2.1]octane derivatives was synthesized and evaluated as potential ligands for neuronal nicotinic acetylcholine receptors in [3H]cytisine labeled rat brain. The 2β-isoxazolyl-8-azabicyclo[3.2.1]octane 9b (Ki=3 nM) was the most potent compound of the series with a binding affinity twice that of nicotine. The 3β-isoxazolyl-8-azabicyclo[3.2.1]octane 15b (Ki=148 nM) exhibited moderate affinity while the corresponding 2α- and 3α-isomers exhibited micromolar binding affinity.

A series of 3-{2-(diarylmethoxyethylidene)}-8-alkylaryl-8-azabicyclo[3.2.1]octanes was synthesized and the binding affinities of the compounds were determined at the dopamine and serotonin transporters. The 8-phenylpropyl analogues 8a (Ki=4.1 nM) and 8b (Ki=3.7 nM) were the most potent compounds of the series with binding affinities 3 times greater than GBR-12909. In addition, 8a (SERT/DAT=327) was over 300-fold more selective for the dopamine transporter than the serotonin transporter.Graphic

A series of 3α-benzyl-8-(diarylmethoxyethyl)-8-azabicyclo[3.2.1]octanes was synthesized and the binding affinities of the compounds were determined at the dopamine transporter. The unsubstituted analogue 7b (Ki=98 nM) was the most potent compound of the series with binding affinity three-times greater than cocaine and only 5-fold less than GBR-12909. The structure–activity data for 7a–f suggests that these compounds may be binding at the dopamine transporter in a similar fashion to GBR 12909.Graphic