- Toxicity of (22R,23R)-22,23-dihydroxystigmastane derivatives to cultured cancer cells
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Toxicity of eight 22,23-dihydroxystigmastane derivatives (four pairs of (22R,23R)- and (22S,23S)-isomers differing in steroid backbone structure) to human breast carcinoma MCF-7 cells was compared. For every pair of structurally related compounds, (22R,23
- Misharin, Alexander Yu.,Mehtiev, Arif R.,Zhabinskii, Vladimir N.,Khripach, Vladimir A.,Timofeev, Vladimir P.,Tkachev, Yaroslav V.
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- New route for the synthesis of (22S,23S)-28-homobrassinolide
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A new and highly efficient synthesis of (22S,23S)-28-homobrassinolide (3) has been achieved. (2α,3α,22S,23S)-Tetrahydroxy-5α-stigmastan-6-one (4), a key intermediate for the synthesis of 3, and (2α,3α)-dihydroxy-5α-stigmast-22-en-6-one (6), a versatile intermediate for the synthesis of 3, and several naturally occurring brassinosteroids have been obtained in excellent yield from stigmasta-2,(22E)-dien-6-one (5) by catalytic RuO4 hydroxylation. Sodium perborate, a cheap and large-scale industrial chemical is used for Baeyer-Villiger oxidation of B-ring ketone 9 to its lactone 10.
- Massey, Archna P.,Pore, Vandana S.,Hazra, Braja G.
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p. 426 - 430
(2007/10/03)
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- SYNTHESIS OF 22S,23S-BRASSINOSTEROIDS BASED ON STIGMASTEROL
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The analogs of 29C-brassinosteroids based on stigmasterol , i.e., 22S,23S-homocastasterone and 22S,23S-homobrassinolide, were synthesized.Electrophilic additions at the Δ22-bond, hydroxylation with osmium tetroxide, and epoxidation followed by conversion of the epoxide into the diol were used for the construction of the 22S,23S-diol grouping.
- Akhrem, A. A.,Lakhvich, F. A.,Khripach, V. A.,Kovganko, N. V.,Zhabinskii, V. N.
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p. 686 - 692
(2007/10/02)
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- Synthesis of (2R,3S,22S,23S)-2,3,22,23-Tetrahydroxy-B-homo-7-aza-5α-stigmastan-6-one, an Aza-analogue of Homobrassinolide
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(2R,3S,22S,23S)-2,3,22,23-Tetrahydroxy-B-homo-7-aza-5α-stigmastan-6-one, an aza-analogue of homobrassinolide, has been synthesized starting with 5α-stigmasta-2,22-dien-6-one.Osmylation of the trimethylsilyl enol ether of this dienone afforded (2R,3S,7S,22S,23S)-2,3,7,22,23-pentahydroxy-5α-stigmastan-6-one, which by oxidation of the acyloin group, after protection of the glycolic systems, afforded (by esterification) an aldehydo ester, which is the key intermediate for the production of the final compound by reductive amination.
- Anastasia, Mario,Allevi, Pietro,Ciuffreda, Pierangela,Fiecchi, Alberto,Scala, Antonio
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p. 2117 - 2122
(2007/10/02)
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- SYNTHESIS OF (22S,23S)-HOMOBRASSINOLIDE AND BRASSINOLIDE FROM STIGMASTEROL
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(22S, 23S)-Homobrassinolide (2α, 3α, 22S, 23S-tetrahydroxy-24S-ethyl-B-homo-7-oxa-5α-cholestan-6-one) and brassinolide (2α, 3α, 22R, 23R-tetrahydroxy-24S-methyl-B-homo-7-oxa-5α-cholestan-6-one) were synthesized from stigmasterol and shown to promote plant growth.
- Mori, Kenji,Sakakibara, Masayuki,Ichikawa, Yoshitaka,Ueda, Hiraki,Okada, Katsuhide,et al.
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p. 2099 - 2110
(2007/10/02)
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- Synthesis of (22R,23R)-28-Homobrassinolide
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(22R,23R)-28-Homobrassinolide (18), an analog of brassinolide (1), was synthesized from stigmasterol (3).Keywords - brassinolide; plant growth-promoting substance; active analogs of brassinolide; structure-activity relationship; stigmasterol; plant hormones; Baeyer-Villiger oxidation
- Takatsuto, Suguru,Ikekawa, Nobuo
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p. 4181 - 4185
(2007/10/02)
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- Synthesis and Plant Growth-promoting Activity of Brassinolide Analogues
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The analogues of brassinolide, 15, 19-23 and 30, were synthezised via key intermediate 5 from stigmasterol.Compound 15 which has the same functional groups as brassinolide on rings A and B showed one tenth of the activity of brassinolide in the lamina inclination test on rice seedlings.However, other analogues with modified ring A were poorly active, and an analogue with modified ring B, 6-oxa-ketone 30, showed only one hundredth of the activity of its 7-oxa-ketone isomer, 29, suggesting that the 2α,3α-dihydroxy-7-oxa-6-ketone moiety is one of the requisites fro the biological activity.
- Wada, Kojiro,Marumo, Shingo
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p. 2579 - 2586
(2007/10/02)
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