Indonesian propolis: chemical composition, biological activity and botanical origin

From a biologically active extract of Indonesian propolis from East Java, 11 compounds were isolated and identified: four alk(en)ylresorcinols (obtained as an inseparable mixture) (1-4) were isolated for the first time from propolis, along with four prenylflavanones (6-9) and three cycloartane-type triterpenes (5, 10 and 11). The structures of the components were elucidated based on their spectral properties. All prenylflavanones demonstrated significant radical scavenging activity against diphenylpicrylhydrazyl radicals, and compound 6 showed significant antibacterial activity against Staphylococcus aureus. For the first time Macaranga tanarius L. and Mangifera indica L. are shown as plant sources of Indonesian propolis.     

Six Membered Heterocycles in the Reaction of Sulfenyl Chlorides with Dialkyl 2-Chloro-2(1-cyclohexenyl)-ethenylphosphonates

Abstract

In the reaction of dialkyl 2-chloro-2(1-cyclohexenyl)ethenyl-phosphonates with methyl- and arylsulfenyl chlorides, a hetero-cyclization of the 1,3-dienylphosphonate system of double bonds (O?P?C?C?C?C) occurs leading to the formation of six-membered heterocycles - hexahidrobenz-2H-1,2-oxaphosphorines:     

Nucleophilic Addition-Oxidation Reactions of σ3,λ3 Dialkyl(Silylamino)Phosphines with Mono and Disubstituted Acetylenes

Abstract:

Dialkyl(silylamino)phosphines R₂PNT₂ undergo a nucleophilic addition-oxidation reaction with either mono- or di-substituted acetylenes which is followed by a silyl migration to form phosphoranimines with unsaturated substituents. The reaction route depends on the substituent on the acetylenic carbon atom. Reactions of the acetylenes with dialkyl(silylamino)phosphines show high chemo and regio selectivity for addition to the triple bond in the formation of the alkene phosphoranimines. The reaction of (silylamino)-phosphines with α,β-acetylenic carbonyl compounds is more complicated; the reaction route depends critically on the substituents at both the carbonyl and the β-acetylenic carbon atoms.     

Application of mean‐separation‐works method to protein crystal nucleation

Using mean‐separation‐works method of Stranski and Kaischew calculations of nucleus form and energy barrier for its formation are performed for globular protein crystals. This is done on the basis of a simple model suggested for crystal nucleation of such proteins. The prerequisite for the model is the fact that strict selection of definite sticky patches on protein molecule surface is obligatory for forming crystal lattices. The calculation results are in agreement with experimental data. (© 2008 WILEY ‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

End-functionalized π-conjugated oligomeric materials for photoelectrical applications

Soluble poly(diphenylacetylene)s (PDA) capped with PhCO- groups (PDA-C) and Ph₂C= groups (PDA-P) were prepared via McMurry reductive coupling of benzil and carbonyl-olefin exchange reaction of tetraphenylethene and benzil, respectively. Fluoren-9-ylidene groups have been introduced into PDA by the McMurry coupling of PDA-C with fluoren-9-one and via copolymerization of benzil and fluoren-9-one. The oligomers prepared are stable in air, soluble in a variety of solvents. They can be processed by casting to form good-quality thin films suitable for measurements of electrical and optoelectrical properties.