Synthesis of (22R,23R)‐ and (22S,23S)‐[4‐14C]‐24‐EPIBRASSINOLIDE

Seo, Shujiro; Nagasaki, T.; Katsuyama, Yoshihiko; MATSUBARA, F.; Sakata, Takako; Yoshioka, M.; Makisumi, Yasuo

doi:10.1002/jlcr.2580271205

Cited by 16 publications

(9 citation statements)

References 9 publications

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“…The first approach to BR radiolabeling was reported by Seo et al Carbon‐14 was introduced into the position C‐(4) of the steroid skeleton at an early stage of a synthetic sequence of more than 10 steps. This led to low radiochemical yields of 3.2% and 4.5%, respectively, of synthesized (22 R ,23 R )‐ and (22 S ,23 S )‐24‐[4‐ 14 C]epibrassinolide.…”

Section: Introductionmentioning

confidence: 99%

Enantiospecific tritium labeling of 28-homocastasterone

Elbert

Patil

Marek

2017

J. Label Compd. Radiopharm

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A regiospecific and enantiospecific synthesis of tritium-labeled 28-homocastasterone is reported. Appropriate chlorocarbonate, efficiently synthesized from the starting 28-homocastasterone in an overall yield of 46%, undergoes catalytic tritium dechlorination by the T /Pd[0]/Et N system, providing 28-[3β- H]homocastasterone, in a good yield, radiochemical purity (>97%), and with a high specific activity (5.8 Ci/mmol).

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Section: Introductionmentioning

confidence: 99%

Enantiospecific tritium labeling of 28-homocastasterone

Elbert

Patil

Marek

2017

J. Label Compd. Radiopharm

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“…For investigations of biosynthesis, metabolism, transport and distribution especially the preparation of radioactive labelled brassinosteroids is important, whereas only few studies in this direction have been done hitherto.Thus, starting from dolicholide via catalytically tritiation [24,28-3H2]-brassinolide and [24,28-3H2]-24-epibrassinolide were prepared [4]. Also a synthetic pathway leading to [4-1%]-24-epibrassinolide has been published [5].…”

Section: Introductionmentioning

confidence: 99%

“…In this communication we report a convenient method for the preparation of [5,7,7-3H3]-24-epibrassinolide (I) starting from 24-epicastasterone tetraacetate (U or bis-isopropylidenedioxy-24-epicastasterone 0. Compounds l a n d 8 are readily available key intermediates of the 24-epibrassinolide synthesis from ergosterol [6].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of tritium labelled 24‐epibrassinolide

Kolbe

Marquardt

Adam

1992

Labelled Comp Radiopharmac

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SUMMARYDeuterium and tritium 5,7,7-tris-labelled 24-epibrassinolide were prepared by base catalyzed exchange reaction using 24-epicastasterone tetraacetate I or bis-isopropylidenedioxy-24-epicastasterone 8 and labelled water. Baeyer-Villiger oxidation of the obtained labelled 6-ketones 2 and 3 with CF3C03H gave after alkaline deacetylation of the resulting 4 and 5 the desired tris-labelled 24-epibrassinolides 6 and 2, respectively, or starting from 9 under simultaneous oxidation and deprotection in one step the same final products.

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“…1 More than 70 of these plant-growth regulators have been discovered so far. 7 The rst approach to BR radiolabeling was reported by Seo et al 8 Carbon-14 was implanted into position C-(4) of the steroid skeleton at an early stage of a synthetic sequence of more than ten steps. 6 The highest biological activity has been found in BRs containing 2a,3a-and 22R,23R-diol functions and a lactone or ketone moiety in ring B (Fig.…”

Section: Introductionmentioning

confidence: 99%