A crystalline organic substrate absorbs methane under STP conditions

A well-known host compound readily absorbs methane at room temperature and pressures of one atmosphere and lower.     

Proton magnetic resonance studies of compounds with bridgehead nitrogen. 37–a comparison of the positions of conformational equilibria in 1-methylperhydro-oxazolo[3,4-a]pyridines and in 1-methylperhydrothiazolo [3,4-a]pyridines

cis(1-H, 8a-H)-1-Methylperhydro-oxazolo[3,4-a]pyridine and cis(1-H, 8a-H)-1-methylperhydrothiazolo[3,4-a]pyridine both adopt exclusively the trans-fused conformation in carbon tetrachloride solution at room temperature. Both parent unsubstituted systems exist under similar conditions as equilibria containing c. 67% (oxazolo compound) and 64% (thiazolo compound) of the trans-fused conformation. In marked contrast to these similar positions of conformational equilibria in both systems the trans(1-H,8a-H)-1-methylperhydrooxazolo[3,4-a]pyridine exists as c. 73% trans-fused in equilibrium with a cis-fused conformation whereas the trans(1-H, 8a-H)-1-methylperhydrothiazolo[3,4-a]pyridine exists almost exclusively in a cis-fused ring conformation. These differences in conformational equilibria are explained in terms of changes in non-bonded interactions.     

A direct correspondence between charge transfer to solvent spectra and electrochemical data and theories: a linear relationship up to 10 mol dm−3 and precise madelung constants from spectral shift data

The shift in E_max for the CTTS spectrum of iodide on addition of alkali chlorides is definitively related to their mean activity coefficients. The relative contributions to the coulombic interaction of the Debye—Hückel and expanded-lattice models are determined by a new precise procedure, yielding accurate Madelung constants.     

O(3P) + HOONO2 → products: Temperature-dependent rate constant

The title reaction was studied in a stirred-flow reactor at six temperatures ranging from 228 to 297 K and for pressures near 2 torr. The experiments were performed under O-atom-rich conditions, and the HOONO₂ concentration was monitored with a modulated molecular-beam mass spectrometer. O-atom concentrations were measured by titration with NO₂ and by monitoring the portion of O₂ dissociated in the microwave discharge. A weighted least-squares analysis gives (k ± 1σ) = (7.0 ± 12.2) × 10^?11 exp(-3369 ± 489/T) cm³/s, where the uncertainties are 1 standard deviation (six temperatures) the covariance was σ_AB = 5.97 × 10^?8. Due to the possible presence of systematic errors, the uncertainty in the rate constant could be as great as a factor of 2 over the entire temperature range.     

Rotational isomerism in 3-mono-oxygenated and 3,7-di-oxygenated derivatives of N-acetyl-17-aza-D-homoandrost-5-ene

The ¹H n.m.r. spectra of 3-mono-oxygenated and 3,7-dioxygenated N-acetyl-17-aza-D -homoandrost-5-enes show unequal populations of the amide rotational isomers in chloroform-d₁ solution. The populations are dependent upon the orientation of the C-7 oxygen substituent but are independent of concentration. In pyridine-d₅ solution the two rotameric states for each compound are almost equally populated.     

Synthesis of lepiochlorin,an antibiotic metabolite of a fungus cultivated by ants

The fungal metabolite lepiochlorin has been synthesized from allylmethoxyethoxymethyl ether and the dianion of 2-phenylthiopropionic acid. The resulting lactone was converted to the butenolide and halogen functions introduced by hydrolysis of the MEM group and treatment with thionyl chloride followed by N-bromosuccinimide. Reaction with silver acetate yielded lepiochlorin.     

Electrophilic Substitution of 1,3-Dimethoxybenzene By Pentadienyltricarbonyliron Cations

Kinetics of reactions of several open-chain pentadienyltricarbonyliron cations with 1,3-dimethoxybenzene have been studied; the reactions are faster than those of the cyclohexadienyltricarbonyliron cation and a mechanism is proposed.