Phytochemistry 2001-11-01

Synthesis and bioactivity of natural and C-3 fluorinated biosynthetic precursors of 28-homobrassinolide.

L R Galagovsky, E G Gros, J A Ramírez

Index: Phytochemistry 58(6) , 973-80, (2001)

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Abstract

In this paper we describe the synthesis of two new fluorinated brassinosteroids: (22R,23R)-22,23-dihydroxy-3alpha-fluorostigmastan-6-one and (22R,23R)-22,23-dihydroxy-3beta-fluorostigmastan-6-one. Their bioactivities were evaluated in the rice lamina inclination test and compared with that of 28-homocastasterone, 28-homotyphasterol and 28-homoteasterone, possible biosynthetic precursors of 28-homobrassinolide. Results confirmed expected similarities between the biosynthesis of 24-ethylbrassinosteroids (named as the 28-homo series) and that described for 24-methylbrassinosteroids, and also indicated that these precursors might exhibit per se activities.