Volume 79, Issue 10-11

A convenient and concise base-promoted synthesis of 3,4-dihydro-2(1 H )-quinazolinones and multi-membered cyclic ureas has been developed. In the presence of t BuOK, a variety of 3,4-dihydro-2(1 H )-quinazolinones as well as the N -arylated five-, six- and nine-membered cyclic ureas were readily synthesized under mild conditions. This method offers an alternative synthesis toolkit towards cyclic ureas.

The stannides SrPdSn (TiNiSi type, orthorhombic space group Pnma ) and m-BaPtSn (EuNiGe type, monoclinic space group P 2 1 / c ) were synthesized from the elements in sealed tantalum ampoules in a high-frequency furnace. Their structures were refined from single-crystal X-ray diffraction data. SrPdSn crystallizes directly from the melt and is stable upon annealing at T = 1073 K. A BaPtSn sample quenched from the melt adopts the cubic LaIrSi-type structure, cubic space group P 2 1 3 (c-BaPtSn) and shows a temperature induced (annealing at 1070 K) structural phase transition leading to a EuNiGe-type low-temperature modification m-BaPtSn. The phase transition leads to a reconstruction within the polyanionic [PtSn] δ − network. The latter is three-dimensional and composed of ten-membered Pt 5 Sn 5 rings in c-BaPtSn, while the polyanion is two-dimensional in m-BaPtSn and is composed of condensed Pt 4 Sn 4 and Pt 2 Sn 2 rings. The two-dimensional substructure leads to a strong moisture sensitivity for m-BaPtSn. The Pt–Sn distances in both modifications range from 257 to 267 pm, indicating substantial covalent bonding.

Overweight and adiposity are of increasing actual importance. The title compounds from traditional Asian medicine raised actual interest for their anti-adipogenic properties. Of the 16 compounds synthesized in previous work, four were subject of X-ray diffraction analyses, three of them, by CSD code designated JUQKIS (CCDC 1886088), JUQKUE (CCDC 1894160) and JUQKOY (CCDC 1886089) were chosen for the present electron density study based on the invariom formalism. The major chemical difference arising from the terminal keto group in the JUQKIS and JUQKOY derivatives and one of the hydroxyl groups in JUQKUE is discussed as the potential source for different biological activities. Details of the intermolecular interactions and the electron densities in the regions in question were examined.

Eu 3 Cl 2 [AsO 3 ][As 2 O 5 ] ( a  = 541.45(4) pm, b  = 837.46(6) pm, c  = 1107.56(8) pm, α  = 90.059(2)°, β  = 94.628(2)°, γ  = 90.449(2)°) and Gd 3 Cl 2 [AsO 3 ][As 2 O 5 ] ( a  = 539.89(4) pm, b  = 838.20(6) pm, c  = 1103.10(8) pm, α  = 90.056(2)°, β  = 94.601(2)°, γ  = 90.388(2)°) crystallize isotypically with Sm 3 Cl 2 [AsO 3 ][As 2 O 5 ] in the triclinic space group P 1 ‾ $\bar{1}$ with Z  = 2. Colorless, transparent, platelet-shaped single crystals of Eu 3 Cl 2 [AsO 3 ][As 2 O 5 ] and Gd 3 Cl 2 [AsO 3 ][As 2 O 5 ] were obtained by solid-state syntheses from their binary components in fused silica ampoules at temperatures around 800 °C.

Propiolamide and cellocidin were investigated in superacidic media. In both acetylenic amides, the amide moiety is immediately monoprotonated in anhydrous HF, HF/SbF 5 and HF/BF 3 . An increase of SbF 5 does not lead to a more highly protonated species. The salts were characterized by low-temperature Raman, NMR and room temperature IR spectroscopy, as well as by single-crystal X-ray diffraction. The experimental data are discussed together with results of quantum-chemical calculations on the M06-2X/aug- cc -pVTZ level of theory, which are consistent with the observation of pure monoprotonation. The second protonation of the amide moiety or the triple bond is not observed due to the high positive charge caused by the monoprotonation.