Synthesis and plant growth promoting activity of polyhydroxylated ketones bearing the 5α-hydroxy-6-oxo moiety and cholestane side chain

Rosado‐Abón, Anielka; Dios-Bravo, Guadalupe de; Rodríguez‐Sotres, Rogelio; Iglesias-Arteaga, Martı́n A.

doi:10.1016/j.steroids.2012.01.004

Cited by 15 publications

(8 citation statements)

References 16 publications

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“…A large number of reports have shown that the indirect or direct conversion of 3α or 3β-hydroxy steroid in Δ 2 alkenes can take place by following at least three different strategies. The indirect path transforms the alcohol into a good leaving group such as tosylate, which in a subsequent treatment with Li 2 CO 3 /LiBr/DMF in reflux system [25,28,33,34,35] or treatment of mesylate derivatives under the same conditions produces the Δ 2 alkenes [26,36,37,38,39]. On the other hand, an efficient alternative is the direct dehydration of 3α or 3β-hydroxy steroid that is carried out by adsorbing the substrate on silica gel in a reaction catalyzed by copper (II) sulfate [32,40,41,42].…”

Section: Resultsmentioning

confidence: 99%

“…These spatial orientations can be indicated as distances or angles between the oxygen atoms present in a brassinosteroid. However, in recent decades, efforts have been focused on the synthesis of new BR analogs, keeping common patterns of organic functions in the A/B rings and cis-trans fusion between them, as occurs in some natural BRs, but with moderate or dramatic structural changes (shorter side chains, different oxygenated functions, spirostanic, aromatic and cyclic substituents, methyl esters, carboxylic acids) [21,23,24,25]. Surprisingly, some of these analogs have presented very important biological activity.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of Five Known Brassinosteroid Analogs from Hyodeoxycholic Acid and Their Activities as Plant-Growth Regulators

Duran

González

Acosta

et al. 2017

IJMS

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Brassinosteroids (BRs) are plant hormones that promote growth in different plant organs and tissues. The structural requirements that these compounds should possess to exhibit this biological activity have been studied. In this work, a series of known BR analogs 5–15, were synthesized starting from hyodeoxycholic acid 4, and maintaining the alkyl side chain as cholic acid or its methyl ester. The growth-promoting effects of brassinolide (1) and synthesized analogs were evaluated by using the rice lamina inclination assay at concentrations ranging from 1 × 10−8–1 × 10−6 M. Our results indicate that in this concentration range the induced bending angle of rice seedlings increases with increasing concentration of BRs. Analysis of the activities, determined at the lowest tested concentration, in terms of BR structures shows that the 2α,3α-dihydroxy-7-oxa-6-ketone moiety existing in brassinolide is required for the plant growing activity of these compounds, as it has been proposed by some structure-activity relationship studies. The effect of compound 8 on cell elongation was assessed by microscopy analysis, and the results indicate that the growth-promoting effect of analog 8 is mainly due to cell elongation of the adaxial sides, instead of an increase on cell number.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis of Five Known Brassinosteroid Analogs from Hyodeoxycholic Acid and Their Activities as Plant-Growth Regulators

Duran

González

Acosta

et al. 2017

IJMS

View full text Add to dashboard Cite

show abstract

“…Natural occurring BRs show a variety of structural modifications in the A/B ring, but it seems that a vicinal 22 R ,23 R diol structural functionality in the side chain is essential for high biological activity. In recent decades, many BR analogs with structural changes on the A/B rings and/or on the side chain (shorter side chains, different oxygenated functions, spirostanic, aromatic and cyclic substituents, methyl esters, carboxylic acids) have been synthesized [ 8 , 9 , 10 , 11 , 12 ]. Surprisingly, some BR analogs with drastic structural modifications in the side chain have also shown interesting activities as plant growth regulators.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of 2-Deoxybrassinosteroids Analogs with 24-nor, 22(S)-23-Dihydroxy-Type Side Chains from Hyodeoxycholic Acid

et al. 2018

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Natural brassinosteroids are widespread in the plant kingdom and it is known that they play an important role in regulating plant growth. In this study, two new brassinosteroid analogs with shorter side chains but keeping the diol function were synthesized. Thus, the synthesis of 2-deoxybrassinosteroids analogs of the 3α-hydroxy-24-nor, 22,23-dihydroxy-5α-cholestane side chain type is described. The starting material is a derivative from hyodeoxycholic acid (4), which was obtained with an overall yield of 59% following a previously reported five step route. The side chain of this intermediate was modified by oxidative decarboxylation to get a terminal olefin at the C22-C23 position (compound 20) and subsequent dihydroxylation of the olefin. The resulting epimeric mixture of 21a, 21b was separated and the absolute configuration at the C22 carbon for the main product 21a was elucidated by single crystal X-ray diffraction analysis of the benzoylated derivative 22. Finally, lactonization of 21a through a Baeyer-Villiger oxidation of triacetylated derivative 23, using CF3CO3H/CHCl3 as oxidant system, leads to lactones 24 and 25 in 35% and 14% yields, respectively. Deacetylation of these compounds leads to 2-deoxybrassinosteroids 18 and 19 in 86% and 81% yields. Full structural characterization of all synthesized compounds was achieved using their 1D, 2D NMR, and HRMS data.

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“…In addition to their intrinsic biological activity, many naturally occurring steroids have been employed as starting materials for the synthesis of bioactive compounds that include drugs [1], ecdysteroids [2], citotoxic steroids [3][4][5], and plant growth promoting substances [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

NMR Characterization and Crystal Structure of 22-Phenyl-3β-acetoxy-bisnorchol-5-en-22-one

2014

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Palladium catalyzed cross coupling between 3b-acetoxy-bisnorchol-5-en-22-oic acid and phenylboronic acid produced the hereto unknown 22-phenyl-3b-acetoxybisnorchol-5-en-22-one which crystallizes in the monoclinic system with space group P2 1 . The presence of 17b-substituent that bears both the C21 methyl group and the introduced phenylketone moiety provides a twisted conformation on C13-C14 for the D ring with asymmetry parameters (Altona et al., Tetrahedron 24:13-32, 1968): D = 711.4, s m = 47.3 (2), DC 2 (C13-C14) = 5.7 (3), DC s (C13) = 14.0 (3) and DC s (C14) = 21.6 (3)°. The angle 77.20 (8)°between planes of the steroid-ABCD framework and phenyl ring evidences the relative orthogonal positions of these fragments. The 1 H and 13 C NMR characterization of the obtained compound are described.

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Synthesis and plant growth promoting activity of polyhydroxylated ketones bearing the 5α-hydroxy-6-oxo moiety and cholestane side chain

Cited by 15 publications

References 16 publications

Synthesis of Five Known Brassinosteroid Analogs from Hyodeoxycholic Acid and Their Activities as Plant-Growth Regulators

Synthesis of Five Known Brassinosteroid Analogs from Hyodeoxycholic Acid and Their Activities as Plant-Growth Regulators

Synthesis of 2-Deoxybrassinosteroids Analogs with 24-nor, 22(S)-23-Dihydroxy-Type Side Chains from Hyodeoxycholic Acid

NMR Characterization and Crystal Structure of 22-Phenyl-3β-acetoxy-bisnorchol-5-en-22-one

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