title: Synthesis and conformational study of 1,3,2-oxazaphosphorino[4, 3-a]isoquinolines: a new ring system.
abstract: A set of 1,3,2-oxazaphosphorino[4,3-a]isoquinolines 6a,b-9a,b, a new ring system, was synthesized, and their stereochemical and conformational analyses were performed by (1)H, (13)C, and (31)P NMR methods. X-ray measurements were also carried out to confirm the stereochemical assignments and conformational results obtained by means of NMR. Intermediate coupling constants (3)J(P,H) were found for compounds 7 and 9; these do not relate to equilibria between previously reported conformers, but are indicative of new distorted conformational states in solution. The connecting isoquinoline and the steric interaction between the aromatic moiety and the Me-1 substituent can block the oxazaphosphorinane ring. The conformational behavior of compounds 6 and 8 was characterized by the usual chair-twist equilibrium.
authors.affiliation: Institute of Pharmaceutical Chemistry, Albert Szent-Györgyi Medical University, H-6701 Szeged, POB 121, Hungary.
authors.forename: T
authors.initials: T
authors.lastname: Martinek
authors.forename: E
authors.initials: E
authors.lastname: Forró
authors.forename: G
authors.initials: G
authors.lastname: Günther
authors.forename: R
authors.initials: R
authors.lastname: Sillanpää
authors.forename: F
authors.initials: F
authors.lastname: Fülöp
mesh_terms: D007546:Isoquinolines / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D013696:Temperature
chemical_list: D007546:Isoquinolines