Confirmation of structure and synthesis of three new 11β-OH C20 gibberellins from loquat fruit

Abstract

Three new 11b-hydroxy C 20 gibberellins have been isolated from immature loquat fruit and their structures were established as 11b-hydroxy-GA 12 , 11b-hydroxy-GA 15 and 11b-hydroxy-GA 53 , respectively, by direct GCeMS comparisons with authentic samples obtained from gibberellic acid by multistep syntheses. An advanced intermediate ( 30) was prepared in 20 steps from which 6 11b-hydroxy C 20 gibberellins were prepared by parallel routes involving up to a further 5 steps for each sequence. The key steps involved a much improved synthesis of gibberellenic acid derivatives, a Lewis acid catalysed cyclisation of a diazoketone, a domino-hydroboration of a diene and oxidative cleavage of a ketone derived enolate.

Diterpenoids

“…Confirmation has been obtained for the structures of the 11bhydroxygibberellins GA 133 (11b-hydroxyGA 12 ), GA 134 (11b-hydroxyGA 15 ) and GA 135 (11b-hydroxyGA 53 ) by their partial synthesis from gibberellic acid. 234 These gibberellins were detected in loquat fruit, Eribotrya japonica. The influence has been studied 235 of the electron transport protein on the steps involving the formation of GA 14 and GA 4 by the Fusarium (Gibberella) fujikuroi gibberellin mono-oxygenases.…”

Effects of GA₃₊₄ and GA₄₊₇ Application Either Alone or Combined with Prohexadione-Ca on Fruit Development of Japanese Pear ‘Kosui’

“…10 g per extraction) was collected, and analyzed for GA 1 , GA 3 , GA 4 , and GA 34 concentrations by gas chromatography-mass spectrometry-selected ion monitoring (GC-MS-SIM) after purification by high performance liquid chromatography (HPLC). Hormone extraction was performed as described by Ito et al (1999), and HPLC and GC-MS-SIM analyses were conducted as described by Phuoc et al (2008) ]GA 34 ), the extract was concentrated in vacuo, and the aqueous residue was subjected to solvent partitioning to obtain an acidic ethyl acetate-soluble fraction. The resulting residue was pre-purified using a Sep-Pak C18 cartridge (Waters, Milford, MA, USA) followed by a Bondesil DEA (5 g) column.…”

Synthesis of Gibberellic Acid Derivatives and Their Effects on Plant Growth

“…Over the years, more than a hundred GAs have been identified from organisms, amongst which only few compounds are available in large quantities such as the relatively cheap natural derived phytohormone named gibberellic acid (GA 3 ) ( Figure 2 ). The latter can be obtained by fermentation of the fungus Gibberella fujikuroi [ 3 ]. Moreover, GA 3 presents an ideal molecule platform for chemical modifications, as it is a tetracyclic diterpenoid compound containing two hydroxyl groups, a lactone ring, and a carboxyl group.…”