9,10‐Di­methoxy‐4‐methyl‐1,2‐di­hydro‐1‐aza­anthracen‐2‐one (kalasin­amide), a new aza­anthracene alkaloid

A new aza­anthracene alkaloid, namely 9,10‐di­methoxy‐4‐methyl‐1,2‐di­hydro‐1‐aza­anthracen‐2‐one (kalasin­amide), C₁₆H₁₅NO₃, has been isolated from the stems of Polyal­thia suberosa collected in the northeastern part of Thailand. Each of the aromatic rings in the mol­ecule is planar within 0.021 (2) Å. Molecules are linked to form centrosymmetric dimers by N—H?O hydrogen bonds [N?O 2.941 (4) Å].     

Gas-phase polymerization of ethylene over Ti-based Ziegler–Natta catalysts prepared from different magnesium sources

This study focuses on gas-phase polymerization of ethylene using the titanium-based Ziegler–Natta catalysts prepared from different magnesium sources including MgCl₂ (Cat A), magnesium powder (Cat B), and Mg(OEt)₂ (Cat C). During polymerization, different cocatalysts were also used. It was found that Cat C with triethylaluminum as a cocatalyst exhibited the highest activity. This was likely attributed to optimal distribution of active sites on the catalyst surface. It can be observed by increased temperature in the reactor due to highly exothermic reaction during polymerization. By the way, the morphologies of the polymer obtained from this catalyst were spherical, which is more preferable. Besides the catalytic activity, crystallinity and morphology were also affected by the different magnesium sources used to prepare the catalysts.     

The synthesis and crystal structure of 5-acetyl-2'-deoxyuridine

5- Acetyl - 2' - deoxyuridine (1) has been synthesised by treating 2' - deoxy - 5 - ethynyluridine with dilute sulphuric acid. Condensation of the trimethylsilyl derivative of 5-acetyluracil with 2-deox-3, 5-di-O-p-toluoyl-α-d-erythropen chloride gave a mixture of α- and β-anomeric blocked nucleosides from which the α-anomer was isolated and the p-toluoyl groups removed to give 5 - acetyl -1 - (α - d - 2- deoxyerythropentofuranosyl) uracil. Only a poor yield of the β-anomer (1) was obtained by this procedure. The UV spectra and m.p. obtained for 1 differed from the values quoted in the literature. The crystals of 1 are monoclinic, space group P2₁, with a = 9.525, b = 12.16, c = 5.22 Å, β = 92.03° and two molecules in the unit cell. The structure was refined by least-squares calculations to R 3.4% for 1426 observed counter amplitudes. The pyrimidine ring is essentially planar with the acetyl group inclined at 6° to it. The sugar ring has the highly unusual C(4')-exo conformation and the arrangement about C(4')-C(5') is such that O(5') is oriented gauche with respect to both O(1') and C(3'). The glycosidic torsion angle O(1')-C(1')-N(1)-C(6) is 56° (anti conformation).