Phenolic alkaloids

Columbamine. (Items 1, 6, 9, 11, 18, 22 list, p. 328.) This base probably occurs among the phenolic alkaloids of ealumba root, but it has only been isolated in the form of dl-tetrahydrocolumbamine, Cj,H4gN(OH)(OMe)3, m.p. 223-4° (p. 291), which on methylation furnishes dZ-tetrahydropalmatine. 

The latter is a microcrystalline powder, m.p. 265° (efferv.), [a] + 210° (N/10 HCl), gives a Millon reaction and like all the phenolic alkaloids of this group is readily oxidised by nitric acid. 

The specimen examined by King - contained a mixture of alkaloids, which was partially separated by a special process into (a) non-quaternary bases, and (b) quaternary bases. From the former, which was a mixture of phenolic alkaloids, Boehm s protocuridine and a new isomeride of this, u oprotocuridine, were isolated. 

A method for the estimation of the total alkaloids and of non-phenolic alkaloids (emetine fraction) is given in the British Pharmacopoeia, 1932, Addendum VI, which requires the drug to contain not less than 2 per cent, of alkaloids, of which at least 55 per cent, must be non-phenolic bases, calculated as emetine. The British Pharmacopoeia also gives an assay process for emetine in emetine bismuth iodide, the form in which the drug is chiefly used in medicine it is required to contain not less than 25 and not more than 28 per cent, of emetine. In the United States Pharmacopoeia, XIII, both Cephcelis Ipecacuanha and C. acuminata are recognised and must contain not less than 2 per cent, of ether-soluble alkaloids. 

Many thousands of secondary plant compounds have been identified and 400000 are suspected to exist. These numbers provide a great incentive for chemical prospecting (Eisner, 1989). The most prevalent, broad classes of plant secondary compound are phenolics, alkaloids, and terpenoids (Table 11.1). 

Pierce Chemical Co. (14) supplies the reagent under the name Methelute. Their literature describes applications for various sedatives, barbiturates, xanthine bases, phenolic alkaloids and Dilantin. Supelco Inc. also supplies the reagent for barbiturate determinations (30). Care should be taken to insure the column is stable to traces of methanol. Also, chromatographic temperatures must be high enough to insure adequate rates of reaction. 

Anhydrolycorinone, Hippadine, Kalbretorine, Oxoassoanine, Pralosine. The efficient coupling of 7-stannylated indoline 218 and 6-bromopiperonal promoted by Pd(0) complex provided another route [60] to anhydrolycorinone (201), hippadine (202) and the phenolic alkaloid, kalbretorine (222) [61]. 

The basic fraction of Berberis baluchistanica Ahrendt yielded (+)-bal-uchistine (79), C36H38N206, mp 222-224°C (MeOH), [a]g> +333° (c = 0.075, MeOH). The UV spectrum, max 283 nm (EtOH), showed a shift to 290 nm, typical of a phenolic alkaloid, on addition of base. Reaction of 79 with di-... 

N-Methylation of secondary amines is usually accomplished either with CH20/HC02H (Leuckart/Clarke-Eschweiler reaction) or with CH20 followed by NaBH4 reduction. Methyl iodide treatment of secondary or tertiary bisben-zylisoquinoline alkaloids leads ultimately to the bis quaternary salts, and, in the presence of base, phenolic alkaloids are also O-alkylated. For example, lin-doldhamine (165) on treatment with ethyl bromide in 0.5 N ethanolic KOH gave the N,N,0,0,0-pentaethy 1 derivative (108, Section II,C,56) daurisoline was similarly permethylated with Mel and base (68, Section II,C,19). 

Acylation (specifically, acetylation) of secondary nitrogens has occasionally been used to separate or characterize bisbenzyltetrahydroisoquinoline alkaloids, as in the case of tiliamosine (Section II,C, 138). O-Acetylation has been used principally as an adjunct to NMR studies of phenolic alkaloids. For example, comparison of thalictrogamine and its 0,0-diacetate enabled assignment of the hydroxys (209, Section VI,A,2,a). 

The phenolic alkaloid tylophorinidine (C22H2304N mp 216-218° Md5 +105°) was subjected to a spectral reexamination and the... 

E. Brochmann-Hanssen and T. O. Oke, Gas chromatography of barbiturates, phenolic alkaloids, and xanthine bases Flash-heater methylation by means of trimethylanilinium hydroxide, J. Pharm. Sci., 55 370(1969). 

Enzymes of the peroxidase-type which use hydrogen peroxide as the oxidizing species, are capable of performing oxidative coupling of phenolic alkaloids (16). The commercially available horseradish peroxidase as well as peroxidase preparations from potatoes and other sources have been used in conjunction with hydrogen peroxide to perform these transformations. The... 

Secondary plant compounds compounds such as phenols, alkaloids, tannins, organic acids, saponins, terpenes, steroids, essential oils, and glycosides which can deter herbivory and detritivory. 

It has not yet been proven that the coupling of phenolate radicals takes place in the biosynthesis of phenolic alkaloids. However, there is no evidence against, and much circumstantial support for, this proposal. The brilliant work of Zenk1517 has shown that the oxidative step in morphine biosynthesis is carried out by a single P-450 type iron porphyrin enzyme, which has been isolated pure and cloned from the appropriate... 

Exploration of the role of phenolic coupling in alkaloid biosynthesis was continued in a long series of elegant publications51 by Dr D. S. Bhakuni who was associated with the work cited above on morphine biosynthesis. A. R. Battersby and his colleagues also made many important contributions in phenolic alkaloid biosynthesis and participated in the key studies of morphine biosynthesis.52... 

The structure of the phenolic alkaloid, mitoridine (XXVII R = OH), was secured by the demethylation of purpeline (50). 

The central vacuole is a relatively simple aqueous phase that can act as a storage reservoir for metabolites or toxic products. For example, the nocturnal storage of organic acids, such as malic acid, takes place in the central vacuoles of Crassulacean acid metabolism plants (mentioned in Chapter 8, Section 8.5A), and certain secondary chemical products, such as phenolics, alkaloids, tannins, glucosides, and flavonoids (e.g., antho-cyanins), often accumulate in central vacuoles. Compared with the central vacuole, the cytoplasm is a more complex phase containing many colloids and membrane-bounded organelles. Because the central vacuole contains few colloidal or other interfaces, any matric pressure in it is... 

H. serrata and its related genera have been used as folk herbs for the treatment of memory disorder and schizophrenia in the east of China. Phytochemical studies disclosed that these plants contained mainly serratene-type triterpenes and Lycopodium alkaloids.In the early 1970s, Chinese scientists reported that the total alkaloids of H. serrata could relax the striated muscle and alleviate the symptom of myasthenia gravis on the animal model. Biodirected assay caused the phenolic alkaloids fraction to be spotlighted and the following chemical component isolation resulted in the finding of HA. ... 

Tanaha and Zenk isolated three new phenolic alkaloids 13, 14, and 16 from the cell cultures of E. califomica after the action of a yeast elici-tor [41]. These alkaloids are intermediates in the biosynthesis of chelirabi-ne, chelilutine, and macarpine, respectively. 

Liensinine (LXIII), a phenolic alkaloid of molecular formula C37H42O6N2 (mp 95°-99°), was isolated from the drug Lien Tze Hsin [embryo of Nelumbium speciosum Willd. Nelumbo nucifera Gaertn.)] of continental China 36) and from the embryo of Japanese lotus 37). 

Five aporphines and an unknown base (HBr, m.p. 215—218 "C) also isolated Main alakloids were aporphines, but two minor phenolic alkaloids thought to be 1-benzyltetrahydroisoquinolines were also isolated Four aporphine alkaloids also isolated. 

Of five new alkaloids which have been characterized, ledeborine (167 R = Me, r2 = r3 = H, R = OH) is a phenolic alkaloid isolated from Corydalis ledebouriana. The remaining alkaloids, namely raddeanamine (168), rad-... 

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