The synthesis of a series of 1-oxygenated gibberellins starting from GA3 (1) is described. Nucleophilic addition of hydrazoic acid to 3-dehydro GA3 (2) was followed by NaBH4 reduction of the resulting 1 -azido-3-ketones 4 and 5 to the corresponding azido alcohols 8–10, and photolysis of the latter compounds to instable 1-imines which were smoothly hydrolysed to the 1-oxo-3-hydroxy gibberellins 13 and
Synthesis of gibberellin A1, A5, A55 and A60-. Metal-ammonia reduction of gibberellic acid and its derivative.
作者:Masanao SHIMANO、Hiroto NAGAOKA、Yasuji YAMADA
DOI:10.1248/cpb.38.276
日期:——
Treatment of gibberellic acid (1) and 13-O-methoxymethylgibberellic acid (2) with lithium diisopropylamide (LDA), and then with Li in liquid ammonia gave 3-hydroxy diacid 4 and 5, respectively. From the diacid 5, gibberellin A55 (10) and gibberellin A1 (12) were synthesized. Without LDA treatment prior to Li-liquid ammonia reduction, 1 gave diacid 8 from which gibberellin A60 (14) and gibberelin A5 (17) were synthesized.