ChemInform Abstract: Study on the Synthesis of Brassinolide and Related Compounds. Part 15. Formal Synthesis of Brassinolide via Stereoselective Sulfenate‐ Sulfoxide Transformation.

Zhou, Wei; Shen, Z.‐W.

doi:10.1002/chin.199208286

Cited by 2 publications

(2 citation statements)

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“…From the synthetic point of view, the tremendous effort dedicated to obtain a number of synthetic analogs has led to development of some convenient, effective and general methods of synthesis applicable to this compound class [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. In this work, we describe the synthesis of new 2-deoxybrassinosteroid analogs bearing a shorter side chain but retaining the diol function, i.e., a 3α-hydroxy-24-nor-22,23-dihydroxy-5α-cholestane side chain type.…”

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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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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“…In particular, hyodeoxycholic acid (4) has been used because it contains the modifiable organic functions at suitable positions, satisfying the structural requirements on the A and/or B and A/B trans fusion ring and side chain of active brassinosteroids [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. Hyodeoxycholic acid (HDA) extracted from hog bile was initially used as a precursor for steroid synthesis [27].…”

Section: Introductionmentioning

confidence: 99%

Structural Modifications of Deoxycholic Acid to Obtain Three Known Brassinosteroid Analogues and Full NMR Spectroscopic Characterization

et al. 2016

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An improved synthesis route for obtaining known brassinosteroid analogues, i.e., methyl 2α,3α-dihydroxy-6-oxo-5α-cholan-24-oate (11), methyl 3α-hydroxy-6-oxo-7-oxa-5α-cholan-24-oate (15) and methyl 3α-hydroxy-6-oxa-7-oxo-5α-cholan-24-oate (16), from hyodeoxycholic acid (4) maintaining the native side chain is described. In the alternative procedure, the di-oxidized product 6, obtained in the oxidation of methyl hyodeoxycholate 5, was converted almost quantitatively into the target monoketone 7 by stereoselective reduction with NaBH 4 , increasing the overall yield of this synthetic route to 96.8%. The complete 1 H-and 13 C-NMR assignments for all compounds synthesized in this work have been made by 1D and 2D heteronuclear correlation gs-HSQC and gs-HMBC techniques. Thus, it was possible to update the spectroscopic information of 1 H-NMR and to accomplish a complete assignment of all 13 C-NMR signals for analogues 5-16, which were previously reported only in partial form.

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ChemInform Abstract: Study on the Synthesis of Brassinolide and Related Compounds. Part 15. Formal Synthesis of Brassinolide via Stereoselective Sulfenate‐ Sulfoxide Transformation.

Cited by 2 publications

References 1 publication

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

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

Structural Modifications of Deoxycholic Acid to Obtain Three Known Brassinosteroid Analogues and Full NMR Spectroscopic Characterization

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