Alkaloids hydrocyanation

Incompat Acids, alkalies, alum, ammonia water, amyl nitrite benzoates betanaphthol, phenol, calomel, chloral hydrate, copper sulfate, ferric chloride ferrous sulfate chromium trioxide (chromic acid), cinchona alkaloids, hydrocyanic acid iodides iodine Lead subacetate mercuric chloride, orthoform potassium permanganate, resorcinol, sod. bicarbonate sod. salicylate (in powder) soln arsenic and mercury iodide, spirit nitrous ether (unless prescribed with sod, bicarbonate), syrup ferrous iodide, tartar emetic tannic acid, thymol, urethane, infusions of catechu, cinchona, rose leaves and uva ursi tinctures of catechu, ferric chloride, cinchona, hamanielis iodine, kino, and rhubarb. 

Elder leaves contain the alkaloid sambucine, a precursor of hydrocyanic acid, which is somewhat toxic. Thus, the leaves are used only topically in ointments for sprains or bruises. Bruised leaves can be rubbed on the body or worn under a hat to prevent being pestered by insects. Cooled strained leaf tea can be applied to plants to discourage aphids. 

New catalyst design further highlights the utility of the scaffold and functional moieties of the Cinchona alkaloids. his-Cinchona alkaloid derivative 43 was developed by Corey [49] for enantioselective dihydroxylation of olefins with OsO. The catalyst was later employed in the Strecker hydrocyanation of iV-allyl aldimines. The mechanistic logic behind the catalyst for the Strecker reaction presents a chiral ammonium salt of the catalyst 43 (in the presence of a conjugate acid) that would stabilize the aldimine already activated via hydrogen-bonding to the protonated quinuclidine moiety. Nucleophilic attack by cyanide ion to the imine would give an a-amino nitrile product (Scheme 10). 

Achillea alpina L. A. millefolium L. Shi Cao (Siberian yarrow) (aerial part) Alkaloids, essential oils, achillin, flavonoides, betonicine, achilleine, d-camphor, oxalic acids, ether oils, hydroxycinnamic acids, hydrocyanic acids, hydroxybenzoic acids, anthocyanidines, anthraquinones, phytosterines, carotene, coumarins, monoterpene, sesquiterpene glucosides, desacetylmatricarin.33-222-450 Antibacterial, treat menopause, abdominal pain, acute intestinal disorder, wound infection, snakebite. 

L. Berczeller has shown that the presence of acids, chlorides, bromides, iodides, thiocyanates, and morphine accelerate the reaction while the presence of tartrates, sulphates, oxalates, carbonates, mercuric chloride, bromide, iodide, and cyanide, most alkaloids, colloids, proteins, etc., inhibit the reaction. Hydrocyanic acid, unlike other acids, also inhibits the reaction. A. Skrabal has shown that Landolt s reaction has a temp, coeff. greater than unity, so that the velocity of the reaction increases with a rise of temp. but if the system contains an excess of sodium sulphate, the temp, coeff. is less than unity, and the velocity of the reaction decreases with a rise of temp. 

It was mentioned at the beginning of this chapter that alkaloids were among the first catalysts to be used for asymmetric hydrocyanation of aldehydes. More recent work by Tian and Deng has shown that the pseudo-enantiomeric alkaloid derivatives 5/6 and 7/8 catalyze the asymmetric addition of ethyl cyanoformate to aliphatic ketones (Scheme 6.6) [50]. It is believed that the catalytic cycle is initiated by the alkaloid tertiary amine reacting with ethyl cyanoformate to form a chiral cyanide/acylammonium ion pair, followed by addition of cyanide to the ketone and acylation of the resulting cyanoalkoxide. Potentially, the latter reaction step occurs with dynamic kinetic resolution of the cyano alkoxide intermediate... 

Draw structures of ligands derived from the chiral framework of glucose, tartaric acid, binaphthol, and cinchona alkaloids that are used for efficient asymmetric hydrocyanation, epoxidation, hydroformylation, and alkene dihydroxylation reactions respectively. 

Optically pure cyanohydrins serve as highly versatile synthetic building blocks [24], Much effort has, therefore, been devoted to the development of efficient catalytic systems for the enantioselective cyanation of aldehydes and ketones using HCN or trimethylsilyl cyanide (TMSCN) as a cyanide source [24], More recently, cyanoformic esters (ROC(O)CN), acetyl cyanide (CH3C(0)CN), and diethyl cyanophosphonate have also been successfully employed as cyanide sources to afford the corresponding functionalized cyanohydrins. It should be noted here that, as mentioned in Chapter 1, the cinchona alkaloid catalyzed asymmetric hydrocyanation of aldehydes discovered... 

CLXXX, treatment with i Q.hydrocyanic acid, and hydrolysis to inte-gerrinecic acid, CLXXXI. This acid was fed to S. adnatus and the resulting rosmarinine was shown to have 89% of the activity in the carboxyl group of the senecic acid indicative of the acid being incorporated after synthesis into the alkaloid. 

These may be isolated by steam distillation. It is usual to make two such distillations, the first from acid solution, the second from alkaline. About 50-100 gm of tissue is homogenized, mixed with an equal quantity of water, acidified with tartaric acid and steam-distilled until a volume ecpial to the original sample taken has been collected. This distillate will contain neutral and acidic compounds such as hydrocyanic acid, phenol, and phosphorus. The tissue slurry is now made alkaline with sodium hydroxide solution and again subjected to steam distillation. This second distillate will contain basic compounds. The tip of the condenser should be immersed in dilute hydrochloric acid to trap the more volatile bases. The plant alkaloids most likely to be present are nicotine, coniine, arecoline, ephedrine, and sparteine, but a number of synthetic drugs, notably amjihetamine and other sympathomimetic bases, also occur in this fraction. Pethidine may also be isolated by steam distillation. The... 

Phytochemistry Tubers contain poisonous saponins, which produce hydrocyanic acid as a result of hydrolysis, alkaloids (possibly volatile cicutine), lipids, pectic substances, fructosans and 28-30 starch. A carotenoid, lycopene, was found in the fruits (Khahnatov 1964 Chernenko et al. 2000). 

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