13613-87-1

Upstream product

• 77-06-5 (3S,3aS,4S,4aS,6S,8aR,8bR,11S)-6,11-dihydroxy-3-methyl-12-methylene-2-oxo-4a,6-ethano-3,8b-prop-1-enoperhydroindeno[1,2-b]furan-4-carboxylic acid 
• 7647-01-0 hydrogenchloride 
• 7732-18-5 water 
• 77-06-5 gibberellic acid 
• 546-09-8 gibberellenic acid 

Downstream Products

• 427-78-1 (4bS,7S,9aS,10R)-1,7-dimethyl-8-oxo-4b,6,7,8,9,10-hexahydro-5H-7,9a-methanobenzo[a]azulene-10-carboxylic acid 
• 1422160-48-2 4-nitrobenzyl (3S,9R,9aR)-8-methyl-2-methylene-11-oxo-1,2,3,9-tetrahydro-3,9a-ethanofluorene-9-carboxylate 
• 95677-49-9 C₂₅H₂₈O₄S 

Relevant academic research and scientific papers

A ring-distortion strategy to construct stereochemically complex and structurally diverse compounds from natural products

High-throughput screening is the dominant method used to identify lead compounds in drug discovery. As such, the makeup of screening libraries largely dictates the biological targets that can be modulated and the therapeutics that can be developed. Unfortunately, most compound-screening collections consist principally of planar molecules with little structural or stereochemical complexity, compounds that do not offer the arrangement of chemical functionality necessary for the modulation of many drug targets. Here we describe a novel, general and facile strategy for the creation of diverse compounds with high structural and stereochemical complexity using readily available natural products as synthetic starting points. We show through the evaluation of chemical properties (which include fraction of sp 3 carbons, ClogP and the number of stereogenic centres) that these compounds are significantly more complex and diverse than those in standard screening collections, and we give guidelines for the application of this strategy to any suitable natural product.

PROOF OF FORMATION OF AN UNSTABLE CONJUGATED TRIENE ON DECOMPOSITION OF GIBBERELLIN A3 IN WATER

It has been shown by the methods of 1H NMR and high-performance liquid chromatography with recording of UV spectra that in aqueous solutions of gibberellin A3, via gibberellenic acid, an unstable conjugated triene having λmax 326 nm is formed which is readily converted into allogibberic acid and is isolated as a mixture (1:2) with this acid.In the 1H NMR spectrum of the triene, confirming its structure, spin-spin coupling both of the H-5 proton and of the protons of the methyl group with all the H-1, H-2, and the H-3 protons is observed.The precursor of allogibberic acid has been ascribed the structure of (-)-13-hydroxy-19,20-dinorgibberella-1,3,9,16-tetraen-7-oic acid with a conjugated 1,3,9-trienic system.

The Conversion of Gibberellic Acid into Steroid Analogues

The expansion of ring B of the gibberellins by formolysis of the toluene-p-sulphonate of the 7-hydroxymethyl analogue of gibberic acid affords the steroid analogue, 4-methyl-15(14->8α)-abeo-16-noroestra-1,3,5(10)-trien-17-one.

1β-Hydroxygibberellin A5. Preparation and Comparison with Gibberellin A3

The preparation of 1β-hydroxygibberellin A5 from gibberellin A3 is described.Unlike its naturally occurring allylic isomer gibberellin A3, 1β-hydroxygibberellin A5 is stable to aqueous alkali and acid-catalysed aromatisation of ring A does not occur.Reasons for these differences, and for the hitherto unreported 3-epimerisation of gibberellin A3 by base, are discussed in terms of O-alkyl fission of the lactone bridge.