- Synthesis of deuterium-labeled cinnamic acids: Understanding the volatile benzenoid pathway in the flowers of the Japanese loquat Eriobotrya japonica
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Cinnamic acids are widely distributed in plants, including crops for human use, and exhibit a variety of activities that are beneficial to human health. They also occupy a pivotal position in the biosynthesis of phenylpropanoids such as lignins, anthocyanins, flavonoids, and coumarins. In this context, deuterium-labeled cinnamic acids have been used as tracers and internal standards in food and medicinal chemistry as well as plant biochemistry. Therefore, a concise synthesis of deuterium-labeled cinnamic acids would be highly desirable. In this study, we synthesized deuterium-labeled cinnamic acids using readily available deuterium sources. We also investigated a hydrogen–deuterium exchange reaction in an ethanol-d1/Et3N system. This method can introduce deuterium atoms at the ortho and para positions of the phenolic hydroxy groups as well as at the C-2 position of alkyl cinnamates and is applicable to various phenolic compounds. Using the synthesized labeled compounds, we demonstrated that the benzenoid volatiles, such as 4-methoxybenzaldehyde, in the scent of the flowers of the Japanese loquat Eriobotrya japonica are biosynthesized from phenylalanine via cinnamic and 4-coumaric acids. This study provides easy access to a variety of deuterium-labeled (poly)phenols, as well as to useful tools for studies of the metabolism of cinnamic acids in living systems.
- Koeduka, Takao,Nishitani, Shiori,Watanabe, Bunta
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- Isotope labeled 'HEA Moiety' in the synthesis of labeled HIV-protease inhibitors - Part 1
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[(S)-1′-((N-tert-Butyloxycarbonyl)amino)-2S-[2H 5]phenyl-ethyl]oxirane 11, made from [2H 5]-bromobenzene, was transformed into the HIV-protease inhibitors [2H5J-DPH 153893 and [2H5]-DPH 140
- Ekhato, I. Victor,Liao, Yuan,Plesescu, Mihaela
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p. 821 - 835
(2007/10/03)
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- Mechanism leading to the observed product of intramolecular aryl Diels-Alder reaction
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A mechanistic investigation into the recently reported intramolecular aryl Diels-Alder reaction was carried out using deuterium labeling. These studies led to the conclusion that the initial Diels-Alder adduct is isomerized to a highly conjugated tetra-ene intermediate which undergoes a stereospecific suprafacial 1,5-dienyl hydrogen shift to give the observed product.
- Chackalamannil, Samuel,Doller, Darío,Eagen, Keith
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p. 5101 - 5103
(2007/10/03)
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