Jacek G. Sośnicki

Catalytic system containing metallic palladium in the process of methane partial oxidation

The oxidation of methane to organic oxygenates over metallic palladium dissolved in oleum was studied. Methanol was obtained by the transformation of methane into methyl bisulfate and dimethyl sulfate. Subsequently, methanol was formed as a result of ester hydrolysis. The reaction conditions were temperature 160 °C, pressure of methane 3.5 MPa, time 2 h, content of sulfur trioxide in fuming sulfuric acid 30%. Palladium can be recovered and used many times without reduction in the process yield. The byproducts formed in the process may be reclaimed and reused.

Reactions of β-keto thioamides with α,β-unsaturated aldehydes. Synthesis of 6-hydroxypiperidine-2-thiones and 6H-thiopyrans

Mixtures of 3-benzoylated and 3-unsubstituted 6-hydroxypiperidine-2-thione derivatives were formed in the reaction of benzoyl(acetyl) thioacetamides with α,β-unsaturated aldehydes in refluxing ethanol in the presence of catalytic amounts of triethylamine. A mechanism for the debenzoylation was proposed. Derivatives of 6H-thiopyran were obtained when an analogous reaction was carried out in refluxing pyridine. The structures of all compounds were determined with the aid of 1D NMR (1H, 13C, 13C-DEPT-135) and 2D NMR (1H, 1H COSY, 1H, 1H NOESY, 13C, 1H COSY) spectroscopy.

23Na NMR and FT-IR studies of sodium complexes with the ionophore lasalocid in solution

Abstract Lasalocid forms 1:1 or 2:2 complexes with sodium ions. The process of complexation was studied in different solvents at various temperatures by 23 Na NMR. The formation constants and Δ G values were determined. The nature of the complex between lasalocid and Na + ions was also studied by FT-IR spectroscopy. In chloroform, a 2:2 complex of lasalocid and Na + ions is formed. A continuous absorption is observed in the far FT-IR spectrum of this complex. It indicates the large Na + polarizability due to fast fluctuations of the Na + ions in multiminima potentials, in the dimeric structure.

The first quantitative determination of conformational equilibrium in quinolizidine-piperidine alkaloids

Abstract The fraction of the conformer with the boat ring C in the conformational equilibrium in N-methyl-angustifoline (7) in chloroform and benzene solutions was determined to be ca. 34% using coupling constant J7–13β. In angustifoline (5) J7–13β could not be determined directly from the spectra; a simulation gave the result of 4.25 Hz corresponding to ca. 23% of the boat conformer. In tetrahydrorhombifoline (6), rings B and C have a chair conformation. Low temperature 13C NMR measurements seem to corroborate these results qualitatively. Factors influencing conformational equilibria are discussed.

Reactivity and diastereoselectivity of Michael additions of amines to achiral α,β-unsaturated thioamides

Abstract Heterocyclic, aliphatic amines add to acyclic and cyclic α,β-unsaturated thioamides yielding β-amino-functionalized derivatives. In the case of cyclic acceptors, the formation of both kinetic and thermodynamically controlled products is observed. Tailoring of cis or trans products is thus possible. A mechanism for the addition to cyclic acceptors is proposed and evidence presented to support it. Ease of addition is studied in relation to the structure of the acceptors.

Structurally dependent behavior of the nitromethyl group of aliphatic γ-nitrothioamides under nitrile oxide generation reaction conditions

Abstract Treatment of (3-allyl)-4-nitromethylthiolactams with phenyl isocyanate and triethylamine has been found to lead to (3-allyl)-4-isothiocyanatolactams. In the case of 3-unsubstituted 4-nitromethylthiolactams, the retro-Michael addition reaction of the nitromethyl group, affording α,β-unsaturated thiolactams and 4-nitromethyllactams, is also observed. Under the same reaction conditions acyclic (α-allyl)-γ-nitrothioamides have been unexpectedly found to lead to α,β-unsaturated nitriles. Mechanisms for these reactions are proposed.

Synthesis of Polycyclic δ-Lactams with Bridged Benzomorphan Skeleton: Selectivity and Diversity Driven by Substituents

An efficient synthesis of bromofunctionalized 2,6-methano- and 1,5-methano-benzomorphanones, starting from easily available 6-benzyl-3,6-dihydropyridin-2(1H)-ones, is described. Furthermore, the synthesis of bridged benzomorphanones with hitherto not known polycyclic systems containing 2- or 3-azabicyclo[4.1.0]heptane units is developed upon treatment of both 2,6- and 1,5-methanobromobenzomorphans with t-BuOK. The effects of substituents on the diversity and stereoselectivity of both transformations are studied.