title: Synthesis and biological activity of ring-A difluorinated brassinosteroids.
abstract: In this paper we report the synthesis of four ring-A difluorinated analogs of brassinosteroids. The bioactivity of these new compounds was evaluated using the rice lamina inclination test. The results show that one of these analogs elicits a bioactivity comparable to that of 28-homocastasterone, a highly active natural brassinosteroid. This finding suggests that both hydroxyls at C-2 and C-3 in active brassinosteroids are involved as hydrogen bond acceptors in their interactions with the cellular receptor.
authors.affiliation: Departamento de Química Orgánica and UMYMFOR (CONICET-Facultad de Ciencias Exactas y Naturales), Universidad de Buenos Aires, Pabellón 2, Piso 3, Ciudad Universitaria, C1428EGA Buenos Aires, Argentina.
authors.forename: Sofía L
authors.initials: SL
authors.lastname: Acebedo
authors.forename: Fernando
authors.initials: F
authors.lastname: Alonso
authors.forename: Lydia R
authors.initials: LR
authors.lastname: Galagovsky
authors.forename: Javier A
authors.initials: JA
authors.lastname: Ramírez
mesh_terms: D060406:Brassinosteroids; D002777:Cholestanols / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D013256:Steroids / Q000138:chemical synthesis* / Q000737:chemistry*; D013260:Steroids, Heterocyclic / Q000737:chemistry; D013329:Structure-Activity Relationship
chemical_list: D060406:Brassinosteroids; D002777:Cholestanols; D013256:Steroids; D013260:Steroids, Heterocyclic; C023623:brassinolide