Acetic anhydride as a synthetic reagent

Acetic anhydride has been used widely in synthetic organic chemistry, especially in syntheses and transformations of heterocyclic compounds. These utilities are reviewed under the following classification.     

Submanifolds of complex space forms admitting an almost contact metric compound structure

Summary Real hypersurfaces of an almost Hermitian manifold naturally admit an almost contact metric structure and the (f, g, u, v, w, , , )-structure is defined on submanifolds of codimension 3 of an almost Hermitian manifold. We study the so-called semi-invariant submanifolds of a complex space form with almost contact metric compound structure which is a general notion of (f, g, u, v, w, , , )-structure.Dedicated to professor Eulyong Pak on his 60th birthdayThis research was partially supported by Korean Science and Engineering Foundation Grant.     

Fabrication of hollow palladium spheres and their successful application to the recyclable heterogeneous catalyst for suzuki coupling reactions

Novel palladium hollow spheres were synthesized using silica spheres as a template, and they were successfully applied as recyclable heterogeneous catalysts for Suzuki cross coupling reactions.     

Synthesis of pyrimido[4,5-e][1,4]oxazepin-5-ones

Eighteen novel pyrimido[4,5-e][1,4]oxazepin-5-ones were prepared directly via the reaction of either ethyl 4-chloro-2-phenyl-5-pyrimidinecarboxylate (Ia) or ethyl 4-chloro-2-m-chlorophenyl-5-pyrimidinecarboxylate (Ib) with a variety of substituted 2-(alkylamino)ethanols. A typical example was the preparation of 8,9-dihydro-9-methyl-2-phenylpyrimido[4,5-e][1,4]-oxazepin-5(7H)-one (IIa) from the reaction of Ia with 2-(methylamino)ethanol. Hydrolytic cleavage of the lactone ring in IIa with sodium hydroxide solution, followed by acidification with hydrochloric acid afforded 4-[(2-hydroxyethyl)methylamino]-2-phenyl-5-pyrimidinecarboxylic acid (IV). Reactions of IIa with concentrated ammonium hydroxide or hydrazine also caused cleavage of the lactone ring, giving the corresponding amide (V) or hydrazide (VI), respectively. Structural assignments were supported by infrared and nuclear magnetic resonance spectra.