Résonance magnétique nucléaire du carbone-13 de composes oxa- et azabicyclo[3.3.1]- et -[4.2.1]nonaniques

Abstract

.l]nonan-2-ols, provide supplementary inforniation regarding the previously studied structures of these types. Shielding and deshielding due to y and 6 steric interactions wereobserved depending on the substituent. The study of the oxabicyclo[4.2.1]nonanes, substituted or not substituted in positions 2 and 7 by hydroxyl groups, and of the azabicyclo[4.2.1]-nonanes substituted in position 2 by the same group, yields interesting results on the conformational equilibria in these compounds which is caused by the flexibility of the sevenmembered ring. The conformational equilibrium is displaced toward the boat form of the seven-membered ring for the unsubstituted compounds. Goirche conformations are proposed for the other compounds in order to account for the experimental observations; the pure chair and boat forms are excluded. Two ketones also have been studied.[Journal translation] Introduction Les effets de substituants sur les dtplacements chimiques en rmn du 13C ont t t t trts ttudits et peuvent apporter d'importants renseignements d'ordre sttrtochimique (1-3). En particulier les dtplacements

Synthesis and Dopamine Transporter Affinity of 2-(Methoxycarbonyl)-9-methyl-3-phenyl-9-azabicyclo[3.3.1]nonane Derivatives

“…For compounds 6 and 12 − 16 , H(2), H(3), H(4a) and H(4e) were easily differentiated from other ring protons because of the C(2)- and C(3)-substituents. The values of the coupling constants of J 2,3 , J 3,4a , and J 3,4e were consistent with the conformations assigned to related bicyclic ring systems. − A value of ∼13 Hz indicated a trans -diaxial relationship, while ∼6 Hz corresponded to a cis -axial−equatorial or a trans -diequatorial relationship. For example, in compound 12 , H(3) exhibited a trans -diaxial relationship with H(2) ( J = 12.5 Hz) and H(4a) ( J = 12.7 Hz) and a cis -axial−equatorial relationship with H(4e) ( J = 6.5 Hz).…”

“…1 H and 13 C NMR spectroscopy has been found to be very useful for the stereochemical and conformational analysis of the 9-azabicyclo[3.3.1]nonane derivatives. − Accordingly, the stereochemical and conformational assignments of stereoisomers of 6 , 12 − 16 , and 18 were made on the basis of NMR data in similar fashion. For compounds 6 and 12 − 16 , H(2), H(3), H(4a) and H(4e) were easily differentiated from other ring protons because of the C(2)- and C(3)-substituents.…”

Oxymetallation. Part 18. Extensive rearrangement to a [4.2.1 ] skeleton in the bromodemercuriation of 2-bromomercurio-9-oxabicyclo[3.3.1]nonane

“…More carbon tetrachloride (60 cm3) was then added and the mixture was cooled in an ice-bath. A solution of bromine (8 mmol) (6). A solution of bromine (0.85 mniol) in carbon tetrachloride (0.5 cm3) was added dropwise to a stirred solution of (6) (0.85 mmol) in carbon tetrachloride (0.8 em3) at 0 "C. After 15 min, the volatile material was removed at 20 mmHg and collected in a cold trap; this was shown by IH n.m.r.…”