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Updated: Aug 19, 2026

Functionalized Spirocyclic Heterocycle Synthesis and Cytotoxicity Assay
Published on: February 9, 2021
Synthesis and bioactivity of C-29 brassinosteroid analogues with different functional groups at C-6
Javier A Ramírez1, Carme Brosa, Lydia R Galagovsky
1Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria (C1428EGA), Buenos Aires 1428, Argentina.
Abstract:
In this paper, we report the synthesis and bioactivity of four synthetic analogues of 28-homobrassinosteroids, in order to evaluate the influence in bioactivity when the C-6 keto group is replaced by different functional groups. The synthetic analogues are 6-deoxo-28-homocastasterone [(22R,23R)-stigmasta-2alpha,3alpha,22,23-tetraol], 6alpha-hydroxy-28-homocastasterone [(22R,23R)-stigmasta-2alpha,3alpha,6alpha,22,23-pentaol], 6beta-hydroxy-28-homocastasterone [(22R,23R)-stigmasta-2alpha,3alpha,6beta,22,23-pentaol], and [(22R,23R)-6alpha-fluorostigmasta-2alpha,3alpha,22,23-tetraol]. Results indicate that replacement of the 6-keto moiety by an beta or alpha hydroxyl group led to a decrease in activity, whereas the 6-deoxo analogue showed a very low activity, confirming the importance of an electronegative moiety at C-6 to observe hormonal potency. The 6alpha-fluorinated analogue elicited a low activity, similar to that of the 6-deoxo analogue.
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