Synthesis of [26-2H3]brassinosteroids

Synthesis of [7,7‐2H2]epibrassinolide

“…This signal had 18% of the intensity of the same signal for compound 5, which corresponds to 82% deuterium content in compound 13. Removal of the acetonide protecting groups in 13 at the last step provided [7, H 2 ]epibrassinolide 14. The use of this compound in biochemical experiments will be reported elsewhere.…”

“…Key transformations include preparation of 6,7-seco steroidal diacid, its cyclization to a cyclic anhydride followed by a regioselective reduction with NaBD 4 . The obtained [7, H 2 ]epibrassinolide can be used in biochemical experiments when the loss of isotopic label should be avoided. …”

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

“…10 This compound proved to be useful for biochemical and physiological investigations, but because of its relatively low isotopic purity (82%) it could not be used in some experiments. 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.…”

Reversible Conversion In The Brassinosteroid Quartet Castasterone, Brassinolide And Their 3β-Epimers

“…The seedlings were extracted according to the procedure described in Materials and Methods. Triply deuterated brassinosteroids, [26-2 H 3 ]3-epicastasterone, and [26-2 H 3 ]3-epibrassinolide [31] (0.4 µg in 10 µl of 75% EtOH each), were added as internal standards. Several solvent partitioning and chromatographic steps resulted in brassinosteroid-containing fractions, which after derivatization with an excess of dansyl-3-aminophenylboronic acid were analyzed by liquid chromatography (HPLC) with electrospray ionization (ESI) and using an established selected ion-monitoring mass-spectrometric (SIM-MS) detection (HPLC-ESI-SIM-MS) method [10,32].…”

“…C24 were separated from the medium and extracted with MeOH (3 × 80 ml) using an Ultra-Turrax homogenizer. [ [31] (0.4 µg in 10 µl of 75% EtOH each) were added as internal standards before evaporation followed by the procedure described below. Identification of endogenous brassinosteroids 1 to 4 was based on a comparison of retention times and relative intensities of molecular ions.…”