Studies on steroidal plant-growth regulator 25. Concise stereoselective construction of sidechain of brassinosteroid from the intact sidechain of hyodeoxycholic acid: formal syntheses of brassinolide, 25-methylbrassinolide, 26, 27-bisnorbrassinolide and their related compounds
摘要:
A concise stereoselective construction of sidechain of brassinolide (1), 25-methylbrassinolide (3) and 26,27-bisnorbrassinolide (4), which involves beta-alkylative 1,3- carbonyl transposition of the alpha,beta-unsaturated ketones 11 and 34 and alpha, beta-unsaturated methyl ester 26, using the intact sidechain of hyodeoxycholic acid (2) as starting material, is described. The formal syntheses of 1, 3 and 4 were accomplished. In the mean time, 25-methylcastasterone (21), 26,27-bisnortyphasterol (6) and the new 25-methyltyphasterol (5) were also syntehesized.
Studies on steroidal plant-growth regulator 25. Concise stereoselective construction of sidechain of brassinosteroid from the intact sidechain of hyodeoxycholic acid: formal syntheses of brassinolide, 25-methylbrassinolide, 26, 27-bisnorbrassinolide and their related compounds
摘要:
A concise stereoselective construction of sidechain of brassinolide (1), 25-methylbrassinolide (3) and 26,27-bisnorbrassinolide (4), which involves beta-alkylative 1,3- carbonyl transposition of the alpha,beta-unsaturated ketones 11 and 34 and alpha, beta-unsaturated methyl ester 26, using the intact sidechain of hyodeoxycholic acid (2) as starting material, is described. The formal syntheses of 1, 3 and 4 were accomplished. In the mean time, 25-methylcastasterone (21), 26,27-bisnortyphasterol (6) and the new 25-methyltyphasterol (5) were also syntehesized.