- Partial Synthesis of Gibberellin A9 and Gibberellin A9; Gibberellin A5 and Gibberellin A5; and Gibberellin A20 and Gibberellin A20
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The 3α-alcohols, obtained by reduction of 3-didehydrogibberellin A3 methyl ester 13-acetate with lithium borohydride, borodeuteride, and borotritiide, have been converted into the 3β-chloro-derivatives and, hence, by reduction with tri-n-butylstannane followed by hydrolysis, into gibberellin A20, gibberellin A20, and gibberellin A20. Gibberellin A20 has been prepared from the product of the reduction of the 3-thiobenzoate of the 3α-alcohol with tri-n-butylstannane.The 3β-alcohols, minor products of these reductions, have been dehydrated and hydrolysed to give gibberellin A5 and gibberellin A5.The 3α-alcohol, from the lithium borohydride reduction of 3-didehydrogibberellin A7 has been transformed into the 3β-chloro-derivative and the 3-thiobenzoate which, with tri-n-butylstannane, or with tri-n-butylstannane, followed by hydrolysis, yielded gibberellin A9, gibberellin A9, or gibberellin A9.In an analogous way, the product of reduction of 3-didehydrogibberellin A4 with lithium borodeuteride was converted into gibberellin A9.The mass spectral fragmentation of the methyl esters and methyl ester trimethylsilyl ethers of gibberellins are also discussed.
- Beale, Michael H.,Gaskin, Paul,Kirkwood, Paul S.,MacMillan, Jake
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p. 885 - 891
(2007/10/02)
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