Kelly David R, Baker Simon C, King David S, de Silva Deepa S, Lord Gwyn, Taylor Jason P
The Tatem Laboratories, School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK.
Org Biomol Chem. 2008 Feb 21;6(4):787-96. doi: 10.1039/b716915a. Epub 2008 Jan 21.
During studies directed towards the discovery of nitrile hydrolysing enzymes from thermophiles, vanillin aldoxime was incubated with the thermophilic organism, Geobacillus sp. DDS012 isolated from Italian rye grass (Lolium multiflorum) silage. The predominant product was a dihydro-dimer, which could only be characterised by LC-MS. This was initially imagined to be the product of cycloaddition of vanillin aldoxime with the corresponding nitrile oxide, but preparation of the supposed adduct and model studies excluded this possibility. The rate constant for the second order dimerisation of 4-O-acetyl vanillin nitrile oxide was measured (1.21 x 10(-4) M(-1) s(-1), 0.413 M, 25 degrees C) and the (13)C-NMR signal for the nitrile oxide carbon was observed (delta(C) 34.4, br. t (1)J(13)C,(14)N circa 50 Hz). Treatment of vanillin aldoxime with potassium persulfate and iron sulfate gave material with the same LC-MS properties as the natural product, which is therefore identified as 5,5'-dehydro-di-(vanillin aldoxime) 1d formed by phenolic oxidative coupling.
在旨在从嗜热菌中发现腈水解酶的研究过程中，将香草醛肟与从意大利黑麦草（多花黑麦草）青贮饲料中分离出的嗜热微生物嗜热栖热放线菌（Geobacillus sp. DDS012）一起培养。主要产物是一种二氢二聚体，只能通过液相色谱 - 质谱联用仪（LC - MS）进行表征。最初认为这是香草醛肟与相应的腈氧化物环加成的产物，但制备假定的加合物及模型研究排除了这种可能性。测定了4 - O - 乙酰香草醛腈氧化物二级二聚反应的速率常数（1.21×10⁻⁴ M⁻¹ s⁻¹，0.413 M，25℃），并观察到腈氧化物碳的¹³C - NMR信号（δ(C) 34.4，宽峰，t (¹J₁₃C,₁₄N约50 Hz)）。用过硫酸钾和硫酸铁处理香草醛肟得到了与天然产物具有相同LC - MS性质的物质，因此将其鉴定为由酚氧化偶联形成的5,5'-脱氢 - 二 -（香草醛肟）1d。
