Stable Isotope Characterization of the ortho-Oxygenated Phenylpropanoids: Coumarin and Melilotol
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- 作者：Elisabetta Brenna ; Giovanni Fronza ; Claudio Fuganti ; Francesco G. Gatti ; Valentina Grande ; Stefano Serra ; Claude Guillou ; Fabiano Reniero ; and Francesca Serra
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2005
- 出版时间：November 30, 2005
- 年：2005
- 卷：53
- 期：24
- 页码：9383 - 9388
- 全文大小：92K
- 年卷期：v.53,no.24(November 30, 2005)
- ISSN：1520-5118
文摘
The natural abundance 2H NMR spectra of extractive coumarin 10 and of its dihydroderivative melilotol11 produced by baker's yeast reduction has been compared with synthetic materials. Diagnostic forthe differentiation of 10 are the (D/H)
values, which are in the 128.1-133.6 ppm interval for thenatural compounds but 258.5 and 189.8 ppm for the synthetic materials. Such a dramatic differenceis also found for methyl cinnamate 12, which shows (D/H) values of 127.2 and 515.8 ppm,respectively. In extractive 10, the ratio (D/H)4(para)/(D/H)6(ortho) = 1.24 is similar to that observed instructurally related salicin and methyl salicylate. Coumarin 10 is transformed in salicyl alcohol 9,providing diacetate 14, showing in the natural series the trend (D/H)3(meta) > (D/H)4(para) > (D/H)5(meta)~ (D/H)6(ortho). A similar trend is shown also by the synthetic 10. A clear distinction between extractiveand synthetic 10 is obtained through 
18O determinations on 10 and on chroman 13. The bulk 18Ovalues in the extractive series of 10 are 20.3, 23.6, and 22.6”, while those of the aromatic oxygenare 2.3, 0.5, and -0.5”. In the synthetic sample, the values are 12.6 and 5.6”, respectively. As afinal product, the reduction of 10 leads to the dihydroderivative 11. Both the baker's yeast reductionand the catalytic hydrogenation lead to a marked decrease of the deuterium content of 11, which isstronger for the -position than for the 
-position.Keywords: Coumarin; extractive; synthetic; deuterium NMR; chroman; positional 18O values;dihydrocoumarin; methyl cinnamate
values, which are in the 128.1-133.6 ppm interval for thenatural compounds but 258.5 and 189.8 ppm for the synthetic materials. Such a dramatic differenceis also found for methyl cinnamate 12, which shows (D/H) values of 127.2 and 515.8 ppm,respectively. In extractive 10, the ratio (D/H)4(para)/(D/H)6(ortho) = 1.24 is similar to that observed instructurally related salicin and methyl salicylate. Coumarin 10 is transformed in salicyl alcohol 9,providing diacetate 14, showing in the natural series the trend (D/H)3(meta) > (D/H)4(para) > (D/H)5(meta)~ (D/H)6(ortho). A similar trend is shown also by the synthetic 10. A clear distinction between extractiveand synthetic 10 is obtained through 18O determinations on 10 and on chroman 13. The bulk 18Ovalues in the extractive series of 10 are 20.3, 23.6, and 22.6”, while those of the aromatic oxygenare 2.3, 0.5, and -0.5”. In the synthetic sample, the values are 12.6 and 5.6”, respectively. As afinal product, the reduction of 10 leads to the dihydroderivative 11. Both the baker's yeast reductionand the catalytic hydrogenation lead to a marked decrease of the deuterium content of 11, which isstronger for the -position than for the -position.Keywords: Coumarin; extractive; synthetic; deuterium NMR; chroman; positional 18O values;dihydrocoumarin; methyl cinnamate