Synthesis of asymmetric [<sup>75</sup>Se]selenoethers via carbodiimides

Blum, Till; Neumaier, Bernd; Coenen, Heinz H.

doi:10.1002/jlcr.488

Cited by 13 publications

(6 citation statements)

References 23 publications

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“…We have previously reported 3MSeP-ITC and 4MSeB-ITC in broccoli [30], but this is the first report of 4MSeB3-ITC (experimental data in Section 2.2). Also 3MSePOH has not previously been reported in nature, although it has been produced synthetically [62].…”

Section: Discussionmentioning

confidence: 99%

Selenium Application During Radish (Raphanus sativus) Plant Development Alters Glucosinolate Metabolic Gene Expression and Results in the Production of 4-(methylseleno)but-3-enyl glucosinolate

McKenzie

Matich

Hunter

et al. 2019

Plants

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Selenium (Se) is an essential micronutrient for human health, entering the diet mainly through the consumption of plant material. Members of the Brassicaceae are Se-accumulators that can accumulate up to 1g Se kg−1 dry weight (DW) from the environment without apparent ill effect. The Brassicaceae also produce glucosinolates (GSLs), sulfur (S)-rich compounds that benefit human health. Radish (Raphanus sativus) has a unique GSL profile and is a Se-accumulating species that is part of the human diet as sprouts, greens and roots. In this report we describe the effects of Se-fertilisation on GSL production in radish during five stages of early development (from seed to mature salad greens) and on the transcript abundance of eight genes encoding enzymes involved in GSL metabolism. We tentatively identified (by tandem mass spectrometry) the selenium-containing glucosinolate, 4-(methylseleno)but-3-enyl glucosinolate, with the double bond geometry not resolved. Two related isothiocyanates were tentatively identified by Gas Chromatography-Mass Spectrometry as (E/Z?) isomers of 4-(methylseleno)but-3-enyl isothiocyanate. Se fertilisation of mature radish led to the presence of selenoglucosinolates in the seed. While GSL concentration generally reduced during radish development, GSL content was generally not affected by Se fertilisation, aside from the indole GSL, indol-3-ylmethyl glucosinolate, which increased on Se treatment, and the Se-GSLs, which significantly increased during development. The transcript abundance of genes involved in aliphatic GSL biosynthesis declined with Se treatment while that of genes involved in indole GSL biosynthesis tended to increase. APS kinase transcript abundance increased significantly in three of the four developmental stages following Se treatment. The remaining genes investigated were not significantly changed following Se treatment. We hypothesise that increased APS kinase expression in response to Se treatment is part of a general protection mechanism controlling the uptake of S and the production of S-containing compounds such as GSLs. The upregulation of genes encoding enzymes involved in indole GSL biosynthesis and a decrease in those involved in aliphatic GSL biosynthesis may be part of a similar mechanism protecting the plant’s GSL complement whilst limiting the amount of Se-GSLs produced.

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Section: Discussionmentioning

confidence: 99%

Selenium Application During Radish (Raphanus sativus) Plant Development Alters Glucosinolate Metabolic Gene Expression and Results in the Production of 4-(methylseleno)but-3-enyl glucosinolate

McKenzie

Matich

Hunter

et al. 2019

Plants

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“…Furthermore, no volatile radio-selenium side products were observed. However, the choice of [ 75 Se]SeH 2 8 as starting material limits the maximum possible specific activity since it can only be formed in presence of carrier [10].…”

Section: Resultsmentioning

confidence: 99%

Alternative syntheses of [^73,75Se]selenoethers exemplified for homocysteine[^73,75Se]selenolactone

Ermert¹,

Blum²,

Hamacher³

et al. 2001

Radiochimica Acta

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The present work describes two radiosynthetic pathways to prepare homocysteine[ 75 Se]selenolactone 1 starting from n.c.a. [ 75 Se]selenite 2. It was achieved either by alkylation reaction of n.c.a. methyl[ 75 Se]selenide 4 or by hydrolysis of alkylated 1,3-dicyclohexyl[ 75 Se]selenourea 11. N.c.a. methyl[ 75 Se]selenide 4 is available using sulfur as non-isotopic carrier. However, the radiochemical yield of the substitution of 2-tert.-butoxycarbonylamino-4-bromobutyric acid ethylester 5 with n.c.a. methyl-[ 75 Se]selenide is only in the range of 15%-20%. Birch reduction of protected n.c.a. [ 75 Se]selenomethionine 6 formed leads to a RCY of 5%-10% homocysteine[ 75 Se]selenolactone 1. Alternatively, the synthesis of homocysteine[ 75 Se]selenolactone 1 is possible by hydrolysis of the corresponding [ 75 Se]selenouronium salt 11 available by addition of 2-tert.-butoxycarbonylamino-4-bromobutyric acid ethylester 5 to 1,3-dicyclohexyl[ 75 Se]selenourea 10. A method was developed for the synthesis of 1,3-dicyclohexyl[ 75 Se]selenourea 10 by addition of c.a. [ 75 Se]SeH 2 to 1,3-dicyclohexylcarbodiimide, which leads to 20%-30% RCY of c.a. homocysteine[ 75 Se]selenolactone 1.

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“…It is directly used in nucleophilic substitution reaction using the corresponding bromide or tosylate precursors. 156 However, this method is limed to symmetric ca [ 75 157 The second possibility for asymmetric alkyl [ 75 158 The amino acid L-[ 75 Se]selenomethionine (2-amino-4methylselanylbutyric acid) was the most prominent radioselenium-labelled radiopharmaceutical being used as a pancreatic imaging agent. 159 Furthermore, L-[ 75 Se]selenomethionine is taken up into the brain and incorporated into brain protein and thus might be useful for PET in the form of L-[ 73 Se]selenomethionine.…”

Section: Labelling Methods For Radioseleniummentioning

confidence: 99%

“…Basic hydrolysis of [ 75 Se]selenouronium salts yields alkyl[ 75 Se]selenolates, which can be alkylated in situ to yield asymmetric [ 75 Se]selenoethers. An attempt to transfer this method to the nca form failed because the synthesis of hydrogen[ 75 Se]selenide is possible only in the presence of a carrier …”

Section: Selenium‐73mentioning

confidence: 99%

Labelling with positron emitters of pnicogens and chalcogens

Neumaier

2017

Labelled Comp Radiopharmac

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The increasing importance of the positron emission tomography (PET) in clinical diagnosis led to the development of a multitude of radiotracers labelled with positron‐emitting radionuclides of groups 15 (pnicogens) and 16 (chalcogens) of the periodic table of elements. The positron emitters of the endogenous occurring elements nitrogen, phosphorus, oxygen, and sulphur are characterized by very short half‐lives compared with the most commonly used PET radionuclides carbon‐11 or fluorine‐18. Therefore, the potential of their synthesis and possible applications in PET is challenging and limited. On the other hand, the nonstandard positron emitters arsenic‐72, arsenic‐74, and selenium‐73 have half‐lives in the range of hours to days and, thus, are of interest for PET studies of processes with long biological half‐lives, but novel methods have to be developed for their application, especially in the no‐carrier‐added state. This review summarizes recent research concerning the positron emitters of pnicogens and chalcogens for radiolabelling applications.

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Synthesis of asymmetric [⁷⁵Se]selenoethers via carbodiimides

Cited by 13 publications

References 23 publications

Selenium Application During Radish (Raphanus sativus) Plant Development Alters Glucosinolate Metabolic Gene Expression and Results in the Production of 4-(methylseleno)but-3-enyl glucosinolate

Selenium Application During Radish (Raphanus sativus) Plant Development Alters Glucosinolate Metabolic Gene Expression and Results in the Production of 4-(methylseleno)but-3-enyl glucosinolate

Alternative syntheses of [^73,75Se]selenoethers exemplified for homocysteine[^73,75Se]selenolactone

Labelling with positron emitters of pnicogens and chalcogens

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Synthesis of asymmetric [75Se]selenoethers via carbodiimides

Cited by 13 publications

References 23 publications

Selenium Application During Radish (Raphanus sativus) Plant Development Alters Glucosinolate Metabolic Gene Expression and Results in the Production of 4-(methylseleno)but-3-enyl glucosinolate

Selenium Application During Radish (Raphanus sativus) Plant Development Alters Glucosinolate Metabolic Gene Expression and Results in the Production of 4-(methylseleno)but-3-enyl glucosinolate

Alternative syntheses of [73,75Se]selenoethers exemplified for homocysteine[73,75Se]selenolactone

Labelling with positron emitters of pnicogens and chalcogens

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Product

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Synthesis of asymmetric [⁷⁵Se]selenoethers via carbodiimides

Alternative syntheses of [^73,75Se]selenoethers exemplified for homocysteine[^73,75Se]selenolactone