Labeled brassinosteroids for biochemical studies

Abstract

The present paper describes the results of our studies on the synthesis of brassinolide biosynthetic precursors as tools for investigations of new biosynthetic routes leading to brassinosteroids. The corresponding labeled compounds containing three or six deuterium atoms at terminal methyl group(s) of the side chain (in a position ensuring lack of isotopic exchange) were prepared starting from stigmasterol or bisnorcholenic acid. Two strategies for the construction of the carbon skeleton of the side chain were applied in this study: Claisen rearrangement of allylic alcohols and convergent synthesis based on the coupling of 22-aldehydes with appropriate chiral sulfone. More than 20 brassinolide precursors (actual or suspected) have been prepared for metabolic studies that enabled identification of new brassinosteroids and biosynthetic subpathways to brassinolide in Secale cereale and Arabidopsis thaliana.

Chemistry and biochemistry of13C hyperpolarized magnetic resonance using dynamic nuclear polarization

“…Substitution of deuterium ( 2 H) into molecules for analytical study, above its natural abundance (0.0156%), has historically been used to follow chemical and biochemical reactions, 92 and to characterize molecular structure from small molecules 93 to proteins. 94 As a spin 1 nucleus, deuterium is a quadrupole and exhibits scalar coupling ( J -coupling) with other spin 1/2 nuclei using the standard 2 n + 1 rule.…”

Synthesis of deuterium‐labeled (24R)‐methyl brassinosteroids

“…Based on the experience we have gained in brassinolide biosynthetic studies, [11][12][13][14][15] labeling the terminal part of the steroidal side chain was considered as an appropriate solution of the problems connected with low isotopic purity. The present work is an extension of our studies 16 toward synthesis of labeled brassinosteroids for biochemical and other biological applications and deals with the preparation of [26-2 H 3 ]epibrassinolide and its biosynthetic precursors.…”

Synthetic Aspects of Brassinosteroids

“…In most cases, their presence in plants was proven by instrumental methods using the corresponding derivatives as internal standards [44]. Isotopically labeled BSs are especially useful for that purpose [45]. These compounds have to meet certain requirements [46].…”