Cumambrins A and B fromTanacetum santolina
To isolate the lactones, this plant (1350 g), collected in the flowering stage in June, 1975, on the Ustyurt plateau (Karakalpakia) was extracted five times with chloroform, and the solvent was distilled off to dryness. The concentrated residue was treated with aqueous ethanol (i:I), and the precipitate that deposited was filtered off. The neutral substances were extracted from the filtrate with hexane and chloroform. In the chloroform-extracted material two substances were detected with Rf 0.38 and 0.24 [TLC, benzene--methanol (9:1), Silufol UV-254]. This resin (22 g) was chromatographed on silica gel. When the column was eluted with henzene--hexane (7:3) and with benzene, two substances were isolated.
The guaianolides of ambrosia cumanensis HBK : The structures of cumambrins A and B☆
Abstract Cumambrins A and B isolated from Ambrosia cumanensis HBK were shown to be guaianolides with structures Ia and Ib.
Industrial inorganic pigments
General Chemical and Physical Properties Behavior of Pigments in Binders White Pigments Titanium Dioxide Zinc Sulfide Colored Pigments Oxides and Hydroxides Cadmium Pigments Bismuth Pigments Ultramarine Pigments Iron Blue Pigments Carbon Black Properties Production Processes Specialty Pigments Magnetic Pigments Anticorrosive Pigments Luster Pigments Transparent Pigments.