No abstract

D-Glucose was converted into the propargyl silane aldehyde 5, which, on treatment with camphorsulfonic acid, cyclized with retention of silicon. The allenic product (7) was elaborated via ketone 24 into 4, which had previously been converted into D-myo-inositol 1,4,5-tris(dihydrogen phosphate). Selective reduction of the advanced intermediate 24 was accomplished with Bu 2 SnCl 2 / Bu 2 SnH 2 , a reagent mixture that shows a very strong preference for generating equatorial alcohols. The cyclization step leading to allene 7 was studied by examining a number of model compounds; the unusual retention of silicon appears to be limited to highly oxygenated substrates, such as 5 and its all-benzyl analogue (27).

No abstract

Organic extracts of the flowers of Helichrysum kraussii and H. odoratissimum contain several bioactive flavonoids, characterized by 1H NMR, 13C NMR and mass spectrometry. Four flavonoids, 5,6-dihydroxy-3,7,8-trimethoxyflavone, 5,7-dihydroxy-3-methoxyflavone, 3′,4′,5,7-tetrahydroxy-3-methoxyflavone and 3′,4′,3,5-tetrahydroxy-7-methoxyflavone, have antioxidant activity by the DPPH free radical assay, while 5,6-dihydroxy-3,7,8-trimethoxyflavone and 3′,4′,3,5-tetrahydroxy-7-methoxyflavone have promising anti-inflammatory activity.

No abstract