Synthesis and biological activity of brassinolide

Brassinolide (2 alpha, 3 alpha, 22 alpha, 23 alpha-tetrahydroxy-24 alpha-methyl-b-homo-7-oxa-5 alpha-cholestan-6-one), a plant steroid-promoting novel Rapeseed, and its unknown 22-beta-23-beta-isomers were obtained from a mixture of C-24 60:40 Dehydroxampesterol (24 alphamethylstyrene) epimers and brassicasterol (24 beta-methyl) synthesized from Of oysters. The synthesis process favored the formation of 22 beta, 23 beta. For better than the 4: 1 isomer, comparative plant of the growth promoting brassinolide capacities, both natural and synthetic, and its three cis-side chains -glycolic isomers in bean second internodal bioassay that natural and synthetic brassinolide were also active and caused a cleavage of the enters to the 0.1 microgram level. The less active were the 22 beta, 23 beta-isomer of brassinolide. The isomers with the 22 & alpha ;, 23 & alpha; And 24 & alpha; And 22 beta, 23 beta and 24 beta configurations are very active and are required at about 10 times the concentration of brassinolide, to cause the same physiological response. In the first internodal bean bioassay, an auxin-induced growth assay system isolated using bean plants resulted in the 22 beta, 23 beta and 24 beta configuration, a stronger response than brassinolide. Two of the four obtained in the synthesis of the Tetrahydroxyketone isomers are also active in both assays.