218. Bridged ring systems. Part V. Structural assignments in the bicyclo[3,3,1]nonane system by infrared spectroscopy

Abstract

High resolution infrared spectroscopy has permitted a determination of the configurations of the epimeric 1,5-dimethylbicyclo[3,3,l]non-2-en-9-ols. The occurrence of hydrogen bonding (OH+x) in one isomer has been related to gas-liquid chromatographic retention times of these compounds. The appearance of v(CH) and 6(CH,) absorptions at abnormally high frequencies can be correlated with the non-bonded intractions inherent in this ring system, and strongly indicate the unexpected twin-chair conformation for the bicyclo[3,3, llnonane framework.IN view of the semi-rigid nature of the bicyc!o[3,3,l]nonane ring system, an examination of the chemical and physical properties of a series of such compounds was of interest.l In the present work a detailed survey of the infrared spectra has revealed unusual absorptionsHydroxyl stretching absorptions in carbon tetrachloride.

Luciduline: a unique type of Lycopodium alkaloid

“…tively. The absorption of the ketonic carbonyl at An alternate structure, 11, which accommodates higher frequency than in luciduline is, by analogy part structure 6 and which could give rise to 2,6-to other P-dicarbonyl systems (14), ascribed to dimethylnaphthalene by a simple rearrangement its 1,3-relationship with another carbonyl group. (arrows in 11) might also explain the low car-The absorption of the lactam carbonyl at bonyl frequency, since cycloheptanones usually 1640 cm-' indicates that the nitrogen is in a sixabsorb at lower frequency than cyclohexanones.…”

Thermische Umlagerung von Propargyloxy‐cycloheptatrien‐Derivaten

“…H a n C (7) H an C (8) H an C (1) H an C (5) H a n C (6) H an C (6) niittel x 5,75-5,60 3,60-3,35 3,35-3,02 m In nz 5,50 3,60-3,36…”

“…Anschliessend an die Umlagerung des 7-Propargyloxy-cycloheptatriens (1 1) liaben wir noch das thermische Verhalten von 2-Propargyloxy-cycloheptatrieno.n (21) (7) c (4) c (6) c (5) S. Fussnote 4) ; Kopplungskonstanten in Hz. d) Intramolekulare En-Reaktionen, auch vom Typ C-H --f C, sindallerdings in anderen Systemenschon bekannt [22].…”

Triasteranetrione

“…To a stirred solution of 12.10 g (79.7 mmol) p-benzoquinone-mono(ethy1ene)acetal (8) c63 in 500 ml ethanol was added 0.18 g (7.8 mmol) sodium and then, before the sodium had completely dissolved, a solution of 13.89 g (79.7 mmol) acetone-dicarboxylic-acid dimethyl-ester (9) in 100 ml ethanol was added dropwise over 1 h. Towards the end of the addition a colourless solid began to precipitate. Stirring was continued for 24 h, the solvent was evaporated and the dark residue was taken into CHCl, and washed with 5% aq.…”

“…[3.3.l]nonane-3,7,9-trione-9-(ethylene)acetal (6). -Benzoquinone-mono(ethy1ene)acetal (8), recently prepared [6] by the partial hydrolysis of benzoquinone-bis(ethy1ene)acetal (7), was treated with one mol-equivalent of acetone-dicarboxylic-acid dimethylester (9) and a catalytic amount of sodium ethoxide. Two consecutive Michael condensations occurred, the first inteimolecular and the second intramolecular, to yield 86% of 2,4-dicarbomethoxy-bicyclo[3.3.l]nonane-3,7,9-trione-9-(ethylene)acetal (10) as a mixture of stereomers.…”