Stereochemistry of Pinocampheols

Abstract

Catalytic hydrogenation of 1,2-benzanthracene and of its 10-methyl and 10-acetoxy derivatives in the presence of Adams catalyst (usually with a promoter) results in the saturation of the terminal ring of the anthracene system, giving 5,6,7,8tetrahydrides. With the acetoxy compound, which is more susceptible to attack than the other two substances, further hydrogenation results in the reduction of the other terminal ring. There is no indication that the hydrogenation of the benzanthracene derivatives proceeds through the intermediate fixation of hydrogen to the mesopositions, and indeed in one case a 9,10-dihydride was found to yield on hydrogenation a product quite different from the 5,6,7,8-tetrahydride obtained directly from the aromatic hydrocarbon.On reduction with sodium and amyl alcohol, 1,2-benzanthracene and 10-methyl-1,2-benzanthracene are converted into 1',2',3',4',9,10-hexahydro derivatives. New derivatives of the careinogenically active 10-methyl-l,2-benzanthracene which have been submitted to biological tests include the 9,10dihydride, the l',2 ',3',4'-and 5,6,7,8-tetrahydrides, and the 1',2',3',4',9,10-hexahydride.

Stereospecific syntheses of the seven dimethylcycloheptanes

“…Because the metal hydride reduction of both isopinocamphone (7) and pinocamphone (8) have been two of these diols (1 and 2) had been reported in the literature but there was confusion and disagreement as to the stereochemistry of these diols. [4][5][6][7][8][9] We have presented evidence which clarified the stereochemistry of these diols10 and these assignments have been independently confirmed by other workers.11-13 Diols 1 and 2.•-Oxidation of -pinene (5) with potassium permanganate under neutral conditions gives a modest yield of the ketol 6, whereas oxidation 5 6…”

“…While our work was in progress, a report appeared on the preparation of the dimethylcycloheptanes by diazomethane ring expansion. 4 We felt, however, that their preparations did not satisfy our needs for purity and unambiguous stereochemistry. The 1,2 isomers were separated chromatographically, but their relative stereochemistry was not independently assigned.…”

“…The 1,2 isomers were separated chromatographically, but their relative stereochemistry was not independently assigned. The 1,4 isomers, inseparable chromatographically, may have involved epimerization in the ring expansion. Since their physical properties for the 1,4 isomers are completely identical,4 only different chemical routes can guarantee their purity.…”

CONFORMATION OF TERPENES. II. PINOCAMPHEOLS AND PINOCARVEOLS1

“…Isopinocampheol has been prepared by the sodium and alcohol reduction of 2-oxypinocamphone (10). The nature of the reducing agent used suggests that the hydroxy group should be equatorial in isopinocampheol.…”