ABSTRACT
Potential nicotinic acetylcholine receptor (nAChR) ligands have been synthesized in which a methylisoxazole substituent is attached to the 1-position ( 26) of the 2-azabicyclo[2.1.1]hexane ring system or separated by "spacer" atoms ( 21 and 23). With ABT-594 as a model, a range of pyridine heterocycles have been attached to the 1-position via a -CH 2O- spacer ( 11, 14, and 6). The biological evaluation of target compounds showed there was no binding affinity at the alpha4beta2 and alpha3beta4 nAChR subtypes.
Subject(s)
Nicotinic Agonists/chemical synthesis , Nicotinic Agonists/pharmacology , Proline/analogs & derivatives , Receptors, Nicotinic/metabolism , Cell Line , Humans , Ligands , Molecular Structure , Nicotinic Agonists/chemistry , Proline/chemical synthesis , Proline/chemistry , Proline/pharmacology , Structure-Activity RelationshipABSTRACT
6-Benzoyl-3,4-dihydro-(2H)-pyran will protect 1,2,3-triols such as glycerol as their corresponding spiro-[5-phenyl-3,6,8-trioxabicyclo[3.2.1]octane-4,2[prime or minute]-tetrahydropyran]s and 1,2,4-triols (less efficiently) as the corresponding trioxabicyclo[3.2.2]nonanes; the hexol mannitol is converted into the corresponding bis-protected product.
ABSTRACT
Successful nucleophilic substitution at a methylene attached to the bridgehead (1-) position of the 2-azabicyclo[2.1.1]hexane ring system opens the way to construction of novel derivatives having a wider range of functional groups attached to the 1-position via a methylene "spacer" (including the beta-amino acid homologue of 2,4-methanoproline) and provides access to epibatidine analogues containing heterocyclic substituents and also to further homologation at the 1-position. Displacements with loss of a nucleofuge (e.g., loss of mesylate anion from the 1-mesyloxymethyl derivative) require thermal activation but proceed without the rearrangement initially anticipated in such a strained bicyclic ring system. A novel tricyclic carbamate intermediate 17 has been isolated; nucleophilic attack on 17 leads directly to the isolation of N-deprotected substitution products (with concomitant decarboxylation).
