Conversion of rhoeageninediol to coptisine

Reaction of 3‐Aminoquinoline‐2,4‐diones with Isocyanates. Synthesis of Novel 3‐(3′‐Alkyl/arylureido)quinoline‐2,4‐diones and Their Cyclic Carbinolamide Isomers.

“…In accordance with our previous works [1][2][3], all studied compounds provided [M+H] + ions in the positive-ion APCI ms spectra and [M-H]ions in the negative-ion APCI mode, which enabled an unambiguous determination of molecular weights of individual compounds. The fragmentation behaviour also followed the characteristic pattern with the neutral losses as water (∆ m/z 18), NHCO (43), NH 2 CO (44), butene (56), butylamine (73), benzene (78), butylisocyanate (99), phenylisocyanate (119), etc.…”

“…In attempts to influence equilibrium by acid catalysis (p-toluenesulphonic acid in benzene), complicated mixtures of not less than five compounds arose. Under these conditions, a molecular rearrangement probably occurs similar to the rearrangement taking place when reacting amines 1 with urea in acetic acid [1,2], or when boiling compounds 3 and 4 in acetic acid [3]. Transformation of compounds 6 and 7 already take place with ease through boiling in acetic acid, as was found in preliminary experiments.…”

“…The expected 3,3a-dihydro-5H-imidazo[4,5-c]-quinoline-2,4-diones (5) do not arise but a molecular rearrangement takes place, producing novel 2,6-dihydro-imidazo[1,5-c]quinazoline-3,5-diones (2) (Scheme 1). On the contrary, compounds 1 substituted at the lactame nitrogen with alkyl or aryl group react otherwise to give three different types of compounds [2]. Depending on the character of substitution in starting compounds 1, either a molecular rearrangement of the quinolone system to indolinone system comes about with formation of 3-(3-acylureido)-2,3-dihydro-1H-indol-2-ones or 4-alkylidene-1´H-spiro[imidazolidine-5,3´-indole]-2,2´-diones, or expected 3,3a-dihydro-5Himidazo[4,5-c]quinoline-2,4-diones (5) arise.In our recent paper [3] we described that α-aminoketones 1 react with nitrourea in various manner depending on the character of reaction medium.…”

Catharnthus Alkaloids XXXI: Isolation of Ajmalicine, Pericalline, Tetrahydroalstonine, Vindolinine, and Ursolic acid from Catharanthus Trichophyllus Roots

“…Alkaloids (Scheme 11)-The following procedure is a modified version of the method described by Klasek (7). Fraction H" (131 g) was worked up per batch as follows.…”

A New C19-Diterpenoid Alkaloid fromAconitum vilmorinianum

“…由于植物的 产地、气候等因素对其化学成分影响较大, 2008 年, 谭 宁 华 等 [3] 报 道 了 从 该 植 物 中 分 离 得 到 一 个 具 C(8)-C(9)-C(10)三元环体系的新骨架的 C 19 -二萜生物碱. 为了更好的开发利用我国乌头属植物的药用资源, 本课 题组对其进行更深入的系统研究, 从该植物中共分离得 到 20 个化合物(Scheme 1), 其中一个为新的 C 19 二萜生 物碱 epi-16β-hydroxycardiopetaline (1), 其余 19 个已知 化合物分别为: talatisamine (2) [4] , karakoline (3) [5] , sachaconitine (4) [6] , 14-O-veratroylneoline (5) [7] , vilmorrianine A (6) [8] , yunaconitine (7) [9] , condelphine (8) [10] , 14-acetyl-sachaconitine (9) [11] , indaconitine (10) [12] , 14-acetylkarakoline (11) [13] , 14-acetyltalatizamine (12) [14] , cammaconine (13) [15] , isotalatizidine (14) [16] , 8-deacetylyunaconitine (15) [17] , 16β-hydroxycardiopetaline (16) [18] , pseudaconine (17) [19] , columbianine (18), denudatine (19) [20] , panicutine (20) [21] . 新 化 合 物 的 结 构 应 用 HRESIMS, 1D-和 2D-NMR, 单晶 X 射线衍射等方法予 以确证.…”