Gelseminic acid

Rutin (= Quercetin 3-0-Rut Quercetin 3-0-Rha-Glc 3,5,7,3, 4 -Pentahydroxy-flavone 3- 0-Rut Rutoside) (flavonol O-glycoside) Salvianolic acid K (phenylpropanoid) Salviaflaside (glycosylated phenypropanoid) Scopoletin (= Chrysatropic acid Gelseminic acid 7-Hydroxy-6-methoxycoumarin ... 

Hydroxy-6-methoxycoumarin. Scopoletin. Aesculetin 6-methyl ether. Chrysatropic acid. Gelseminic acid, p-Methylaesculetin... 

Gelsemine dissolves in sulphuric acid, giving a colourless solution, which on the addition of a crystal of potassium dichromate becomes red, then violet and finally green. A solution in alcohol gives a pink colour with dimethylaminobeiizaldehyde in hydrochloric acid. 

However, the proposed in vivo transformation of anhydrovobasinediol to gelsemine might involve a series of more extensive alterations of the molecular skeleton which presumably would include (1) oxidation of the 2,7 double bond, (2) an acid-induced 2,7 shift, and (3) allylic rearrangement of the C-20 ethylidene side chain to a C-20 vinyl, so that a humantenine-type precursor... 

Gelsemine, C20H22N2O, mw 366.22 prisms (from acet), mp 178° insol in w sol in ale, ether, chlf, and dilute acids. A poisonous alkaloid obtd from rhizome and root of Gel-semium sempervirens. Used in medicine as an analgesic and antispastnodie Refs 1) Beil 27, [720] 2) T.G. Wormley,... 

Gelsemine, Nitration. Nitration of gelsemine yields only an amorphous material. Nitration of dihydrogelsemine in mixed acid at —7 to +5° gives Dinitrogelsemme, analyzing for C30H22N4O6> mw 458.22, yel ndls (chlf or ale), mp 257—8° sol in chlf, pyridine si sol in acet,. methanol, ale, benz, eth w. The dinttro compd forms a nitrate salt, yel rhomr bic prisms, mp.219—21°dec Ref T.Q. Chou T.T. Chu, JACS 63, 827 (1941) CA 35, 2897 (1941) (Nitration)... 

Gelsemine, C20H22N2O2, mp 178°, [a]D+15.9°, is a strong, mono-acidic base, pK 9.37, which forms salts with only one equivalent of... 

If the molecule is too rigid for the Mannich cyclisation to occur easily, it is possible to carry it out as a separate step. Overman s approach to gelsemine, a very difficult target, involves an anionic aza-Cope rearrangement on 201 and the trapping of the enolate.31 The resulting ketone 202 is cyclised in acidic solution. Evidently the addition of the enol to the protonated imine goes better than the cyclisation of the enolate onto the neutral imine when the final product is as strained as 203. 

In formic acid, the enamine is protonated on carbon to give the very electrophilic immonium ion 208 which cyclises in conformation onto the enol 208a in an intramolecular Mannich reaction to give the bicyclic skeleton 203 required for gelsemine. 

The total synthesis of d/-21-oxo-gelsemine reported by Hart and collaborators (107) features two free radical cyclizations (C-5-C-16 bond formation in gelsemine) to construct both a tricyclic substructure 314 in the terpene part of gelsemine and the spiro-oxindole moiety. The synthesis was initiated with the Diels-Alder reaction between A-methylmaleimide and the diene 302, followed by treatment of the crude cycloadduct with 2,2-dimethyl-l,3-propanediol and a catalytic amount of p-toluenesulfonic acid, to give the perhydro-isoindole 304 in 43% yield. By application of the Grieco dehydra-... 

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