title: Synthesis and bioactivity of natural and C-3 fluorinated biosynthetic precursors of 28-homobrassinolide.
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.
authors.affiliation: Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, 1428, Buenos Aires, Argentina. lyrgala@qo.fcen.uba.ar
authors.forename: L R
authors.initials: LR
authors.lastname: Galagovsky
authors.forename: E G
authors.initials: EG
authors.lastname: Gros
authors.forename: J A
authors.initials: JA
authors.lastname: Ramírez
mesh_terms: D002778:Cholestanones / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D005461:Fluorine / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry / Q000379:methods; D015394:Molecular Structure
chemical_list: D002778:Cholestanones; D005461:Fluorine; C070163:homobrassinolide