Synthesis and HPLC-ECD Study of Cytostatic Condensed -Heterocycles Obtained from 3-Aminoflavanones.

Racemic chiral -heterocycles containing 2-arylchroman or 2-aryl-2-chromene subunit condensed with morpholine, thiazole, or pyrrole moieties at the C-3-C-4 bond were synthesized with various substitution patterns of the aryl group by the cyclization of - or -3-aminoflavanone analogues. The 3-aminoflavanone precursors were obtained in a Neber rearrangement of oxime tosylates of flavanones, which provided the diastereomer as the major product and enabled the isolation of both the - and -diastereomers. The - and -aminoflavanones were utilized to prepare three diastereomers of 5-aryl-chromeno[4,3-b][1,]oxazines.

New insight into the biosynthesis of flavanolignans in the white-flowered variant of Silybum marianum.

It has been demonstrated that besides the known flavanolignan constituents of the white-flowered variant of Silybum marianum, (-)-silandrin A (3a) and (-)-isosilandrin A (4a); their trans-benzodioxane diastereomers, (-)-silandrin B (3b) and (-)-isosilandrin B (4b), are also produced by the plant. Moreover, the isolation of their cis-benzodioxane diastereomers, (-)-isocisilandrin (5) and cisilandrin (6), confirm that the previously proposed biosynthetic pathway involving a nonselective O-beta coupling is correct.

Synthesis and biological activity of the structural analogues of (-)-cabenegrin A-I.

A series of phenylbutene and butanol derivatives (6a-j, 12, 13, 15, 17, 24b,c, 26, 27a,b) were prepared from the readily available resorcinol derivatives 2a-f and 7-hydroxy-chroman (18). The products were tested for inhibitory activity on the LPS-induced TNF-alpha production in the plasma in comparison with that of cabenegrin A-I (1a).