title: Preparation and structural analysis of (±)-cis-ethyl 2-sulfanylidenedecahydro-1,6-naphthyridine-6-carboxylate and (±)-trans-ethyl 2-oxooctahydro-1H-pyrrolo[3,2-c]pyridine-5-carboxylate.
abstract: Bicycle ring closure on a mixture of (4aS,8aR)- and (4aR,8aS)-ethyl 2-oxodecahydro-1,6-naphthyridine-6-carboxylate, followed by conversion of the separated cis and trans isomers to the corresponding thioamide derivatives, gave (4aSR,8aRS)-ethyl 2-sulfanylidenedecahydro-1,6-naphthyridine-6-carboxylate, C11H18N2O2S. Structural analysis of this thioamide revealed a structure with two crystallographically independent conformers per asymmetric unit (Z' = 2). The reciprocal bicycle ring closure on (3aRS,7aRS)-ethyl 2-oxooctahydro-1H-pyrrolo[3,2-c]pyridine-5-carboxylate, C10H16N2O3, was also accomplished in good overall yield. Here the five-membered ring is disordered over two positions, so that both enantiomers are represented in the asymmetric unit. The compounds act as key intermediates towards the synthesis of potential new polycyclic medicinal chemical structures.
authors.affiliation: Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, England.
authors.forename: Carolin
authors.initials: C
authors.lastname: Schwehm
authors.affiliation: School of Chemistry, University Park Nottingham, Nottingham NG7 2RD, England.
authors.forename: William
authors.initials: W
authors.lastname: Lewis
authors.affiliation: School of Chemistry, University Park Nottingham, Nottingham NG7 2RD, England.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Blake
authors.affiliation: Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, England.
authors.forename: Barrie
authors.initials: B
authors.lastname: Kellam
authors.affiliation: Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, England.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Stocks
mesh_terms: D002626:Chemistry, Pharmaceutical; D018360:Crystallography, X-Ray; D006571:Heterocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009287:Naphthyridines / Q000138:chemical synthesis* / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D006571:Heterocyclic Compounds; D009287:Naphthyridines; D011725:Pyridines; D011758:Pyrroles; C000595914:ethyl 2-oxooctahydro-1H-pyrrolo(3,2-c)pyridine-5-carboxylate; C000595913:ethyl 2-sulfanylidenedecahydro-1,6-naphthyridine-6-carboxylate
keywords: GPCRs; NMR evaluation; X-ray crystal structure; bicycle formation; biologically active compounds; medicinal chemistry; polycyclic scaffolds; privileged structure