F. M. Schell

Oil-shale analysis by CP/MAS-13C n.m.r. spectroscopy

Abstract Solid-state 13 C n.m.r. (CP/MAS- 13 C n.m.r.) spectroscopy provides a direct method for estimating potential oil yields of oil shale formations. Relative aliphatic resonance areas correlate linearly with oil yield and provide a method for oil yield estimation that obviates the need to determine weight per cent organic carbon for each specimen. This direct measurement is performed using an internal area standard, the carbonyl resonance of N -(2- 13 C-propanonyl)- N , N , N -trimethylammonium chloride, to monitor spectrometer sensitivity. Oil shale samples obtained as a function of depth at a site in the Mahogany Zone of the Green River Formation show a near-constant aliphatic carbon fraction, f al ≡ (1− f a ), and a twofold, nonlinear variation in oil yield over the vertical dimension of the sampling. Aliphatic carbon resonance band shape changes among these samples are interpreted qualitatively as reflecting a two component mixture composed of the condensed alicyclic structures which link together to form the kerogen matrix and an n.m.r.-distinct but not necessarily chemically distinct contribution from normal -long chain hydrocarbon residues.

A Facile Synthesis of Tetracycles of the γ-Lycorane Type

Abstract When an attempted application of the general scheme of alkaloid synthesis, based on the partial hydrogenation of 1 -alkyl-3-acylpyridinium salts and acid-induced cyclization of the resultant 2-piperideines,2 to the construction of an Amaryllidaceae alkaloid system failed in the cyclization step, i.e. the transformation of dihydroisoquinoline 4a (prepared by the treatment of ester 2a 3 with 5-bromo-2 -pentanone ethylene ketal, followed by hydrogenation of the salt over palladium-charcoal) into a tricyclic ketal ester,4 an alternate, route of synthesis still utilizing a previously prepared isoquinoline precursor (3b) was investigated. The initial observation of the easy conversion of 3b into N-methyl (1a) and O-ethyl products (2b) was helpful in this connection.