Carbon-13 magnetic resonance. XXIV. Perhydroanthracenes and perhydrophenanthrenes

Abstract

The proton-decoupled, carbon-13 magnetic resonance (cmr) data have been determined for all of the five possible perhydroanthracene structural isomers and for four of the six possible perhydrophenanthrene compounds. The former are of known configuration, but the latter are unidentified in the chemical literature prior to the present work. The data are initially assigned to specific carbon positions using a parameter set derived from the methyldecalins. The calculated spectra are then refined by least-squares, regression analysis. New chemical shift parameters associated with boat and skew pentane conformations are discussed.he first tetradecahydroanthracene (or perhydroanthracene, abbreviated for convenience to PHA) isomer was synthesized about the turn of the century.2-4 It was soon recognized that other geometric isomers were possible6 and as many as 20 were suggested.6 Fries and Schilling ultimately delineated the correct number as being five,7 the last of which was synthesized only in recent years.8 Many workers contributed to the synthesis and characterization of the several isomers.7•9-14 X-Ray16 and electron diffraction16•17 work

Ionic liquids. Green solvents for the future

“…For example, pyrene and anthracene can be reduced to perhydropyrene and perhydroanthracene at ambient temperatures and pressures; only the thermodynamically most stable isomer of the product is obtained [23]. This contrasts with catalytic hydrogenation reactions, which require high temperatures and pressures, and an expensive platinum oxide catalyst and give rise to an isomeric mixture of products [24]. By (Fig.…”

The semiempirical derivation of 13C nuclear magnetic resonance chemical shifts. Hydrocarbons, alcohols, amines, ketones, and olefins

“…The derivations of the N-methyl, C(2) and C (10) resonances in N-methyldecahydroquinoline and of the C(10) resonance in 10-methylquinolizidine start from the P, S, T, and Q references, respectively (items Me/72, 2/72, 10172, and 10163). The remaining shift contributions arise from hydrocarbon interactions.…”

β-Carbon Shielding Effects in Carbon-13 Nuclear Magnetic Resonance Spectroscopy

“…There have been a number of attempts to correlate carbon-13 chemical shifts in saturated hydrocarbons with molecular structural features (1)(2)(3)(4)(5)(6). The additivity parameters reported recently by Grant and co-workers (5, 6) appeared to be the best to date, since they were based on conformationally well defined model systems.…”