The Biosynthesis of the phenethylisoquinoline alkaloid colchicine. Early and intermediate stages
作者:Richard B. Herbert、Abdullah E. Kattah、Eric Knagg
DOI:10.1016/s0040-4020(01)87895-9
日期:1990.1
that in the early stages of biosynthesis the major pathway to colchicine (7) and demecolcine (6) is (13)→(15)→(16)→(19). Condensation of the aldehyde (19) with dopamine affords a set of phenethylisoquinolines which are precursors for the alkaloids (6) and (7) and (21) is identified as the first of these followed by (22) and then (1); (39) is by contrast also an exellent alkaloid precursor; it is deduced
The genetic controlled hydroxylation pattern of the anthocyanin b-ring in Silene dioica is not determined at the p-coumaric acid stage
作者:Ria Heinsbroek、Jan van Brederode
DOI:10.1016/s0031-9422(00)82236-0
日期:1980.1
The basic C-15 skeleton of flavonoids is formed by the head-to-tail condensation of three malonyl-CoA units to one molecule of hydroxycinnamoyl-CoA. The A-ring and part of the heterocyclic ring are derivedfrom the acetateunits, the B-ring from the hydroxycinnamoyl ester. The basic C-15 flavonoid is then further modified to yield the various flavonoid classes. In this biosynthetic pathway, the hydroxylation
黄酮类化合物的基本 C-15 骨架是由三个丙二酰辅酶 A 单元头尾相连形成一分子羟基肉桂酰辅酶 A 的。A-环和部分杂环衍生自乙酸酯单元,B-环衍生自羟基肉桂酸酯。然后进一步修饰基本的 C-15 类黄酮以产生各种类黄酮。在该生物合成途径中,B 环的羟基化模式可以在 C-9 水平上通过适当的羟基肉桂酰辅酶 A 酯开始确定,或在 C-15 水平上通过 C- 15个中间体。在 Silene dioica 中,花色素分子 B 环的羟基化模式以及与 3 位末端糖结合的酰基的羟基化模式受基因 P 控制,而酰基的结合受基因 Ac 控制. 然而,酰基的羟基化模式与花色素分子的 B 环的羟基化模式一致。因此,在仅发现天竺葵苷的 p/p Ac/Ac 植物中,酰基是对香豆酸。在 P/P Ac/Ac 植物中,花色素是花青素,酰基是咖啡酸。这表明纯合隐性 p/p 植物无法合成咖啡酸,咖啡酸在花色素分子的生物合成中用
Synthesis of [quinoline-3-14C]-SSR97193 (ferroquine) from [2-14C]-malonic acid
Intermediates in the formation of puberulin by Agathosma puberula
作者:Stewart A. Brown、Raymond E. March、Douglas E.A. Rivett、H. Joan Thompson
DOI:10.1016/0031-9422(88)83105-4
日期:1988.1
comparably to [ 14 Me] scopoletin in puberulinformation, and in two experiments the incorporations of > 1% were among the best that have been observed for any puberulin precursor. Participation of isofraxidin strongly implicates fraxetin as an intermediate. The sequence: p -coumaric acid → → umbelliferone → aesculetin → scopoletin → fraxetin → isofraxidin → puberulin is proposed as a feasible biosynthetic
摘要 14 C 标记的七叶树素的直接测试产生的结果与其先前假定的作为伞形花酮和东莨菪碱之间的中间体在 A. puberula 生物合成小枝花中的作用一致。对该物种的酸性级分进行质谱分析,该级分应包含其所有游离酚类香豆素,表明存在异弗拉西丁和弗拉西丁,这已通过 GC 确认。[8- O - 14 Me] 异夫拉昔定在小枝素形成中的平均利用与 [ 14 Me] 东莨菪碱相当,并且在两个实验中,> 1% 的掺入是观察到的任何小枝素前体的最佳掺入量。isofraxidin 的参与强烈暗示了 fraxetin 作为中间体。序列:
Carbon-14 labelling of selective H3 receptor antagonists
作者:Steen K. Johansen
DOI:10.1002/jlcr.1018
日期:2005.12
The fast and efficient carbon-14labelling of the three potent H3antagonists NNC 38-1202, NNC 38-1384, and NNC 38-1401 is reported. The two-step synthetic sequence, which included a Knoevenagel reaction, provided the carbon-14-labelled compounds in 38–55% overall yield starting from [2-14C]malonic acid. The compounds were all obtained in high radiochemical purity ( > 99%) and with high specific activity