Alternative syntheses of 2α,3α,17β-trihydroxy-7-oxa-B-homo-5α-androstan-6-one and some androstane brassinolide analogs

Kohout, Ladislav; Černý, V.; Strnad, Miroslav

doi:10.1135/cccc19871026

Cited by 11 publications

(8 citation statements)

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“…Synthesis. The simplest fluoro analogue of this series, compound 10 (see Scheme 1), was prepared from the known 17 i-steroid 11: the treatment with sulfuric acid, followed by the reaction of intermediate 3β-alcohol 12 with (diethylamino)sulfur trifluoride (DAST) 12 afforded the 3R-fluoro compound 13, and on deprotection, the target compound 10. Alternatively, i-steroid 14 was first converted into 3β-alcohol and 3R -fluoride 15 and 16, respectively; the 17-oxo group was then selectively reduced with sodium borohydride in pyridine, yielding the above 17βalcohol 10.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Brassinosteroids: Synthesis and Activity of Some Fluoro Analogues

Slavı́ková¹,

Kohout²,

Budêšínský³

et al. 2008

J. Med. Chem.

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Three types of 5alpha-androstane and ergostane analogues of brassinolide, containing a fluorine atom in either the 3alpha or the 5alpha positions or in 3alpha and 5alpha positions, were prepared using standard operations (reaction of 3beta-alcohols with (diethylamino)sulfur trifluoride, cleavage of epoxide with HF in py or BF 3.Et 2O). The 5alpha-fluorine was found to affect chemical reactivity (e.g., electrophilic addition to the Delta (2)-double bond) as well as physical properties (e.g., NMR, chromatographic behavior) of the products. Cytotoxicity of the products was studied using human normal and cancer cell lines with 28-homocastasterone as positive control and their brassinolide type activity was established using the bean second-internode test with 24-epibrassinolide as standard. The equivalence of F and OH groups was observed in some of the active compounds. The anticancer and the brassinolide-type activity do not correlate with each other: ergostane derivatives were most active in the former test while androstane derivatives were best in the latter.

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Section: Resultsmentioning

confidence: 99%

“…The same sequence was repeated with 3R,5-cyclo-5R-ergost-22-en-6-one (17), which was converted into 3β-hydroxy ketone 18. DAST was again used to produce the corresponding fluoride 19.…”

Section: Resultsmentioning

confidence: 99%

Brassinosteroids: Synthesis and Activity of Some Fluoro Analogues

Slavı́ková¹,

Kohout²,

Budêšínský³

et al. 2008

J. Med. Chem.

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“…Kohout and his coworkers combined 2,3,17-trihydroxy-7-oxa-B-homo-5-androstan-6-one containing the steroid moiety of BL with amino acids and found weak activity for some compounds using a bean hypocotyls elongation bioassay. 23) These compounds have an ester bond in the side chain moiety. Synthesis of the ester analogs is attractive, because the ester bond is easily constructed from alcohols and carboxylic acids to derive various analogs.…”

Section: Synthesis Of Brassinosteroids Of Varying Acyl Side Chains Anmentioning

confidence: 99%

Synthesis of Brassinosteroids of Varying Acyl Side Chains and Evaluation of Their Brassinolide-like Activity

Uesusuki

Watanabe

Yamamoto

et al. 2004

Bioscience, Biotechnology, and Biochemistry

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Brassinosteroids containing various side chain moieties were synthesized and their activity was determined as the reciprocal logarithm of the ED(50) (50% effective dose per plant in moles) in the rice lamina inclination assay using synergist indole-3-acetic acid (IAA). The introduction of a hydroxyl group in the alpha-position to the carbonyl group of the ester structure significantly enhanced the activity. 2alpha,3alpha-Dihydroxy-17beta-[(2R,3S)-2-hydroxy-3-methylpentanoyl]oxy-B-homo-7-oxa-5alpha-androstan-6-one showed the highest activity, for which the pED(50) was determined to be 10.5 under synergistic conditions with IAA. Under identical conditions, the pED(50) values of brassinolide and castasterone were determined to be 13.6 and 12.3 respectively. With respect to the alpha-carbon of the acyl moiety, the R-form was 10 times more potent than the corresponding S-form. Substituting the terminal structure (Et) of the side chain to that of the most potent compound, brassinolide (i-Pr), did not increase the activity.

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“…Despite their biological activity was reduced compared to the natural BS, some interesting tendencies were found concerning substituents at C-16 and C-17. This compound was available starting from stigmasterol [118], androstenolone [119], or, as described in Scheme 6.43, from pregnenolone (263) [120]. A series of 3-substituted cholestane derivatives with a lactone moiety in ring B (e.g., 261, 262) was synthesized for antiproliferative studies [117].…”

Section: Bs Analogsmentioning

confidence: 99%