Alkaloids Derived From Tryptophan

L-Tryptophan is an aromatic amino acid containing an indole ring system, having its origins in the shikimate pathway (Chapter 4) via anthranilic acid. It acts as a precursor of a wide range of indole alkaloids, but there is also definite proof that major rearrangement reactions can convert the indole ring system into a quinoline ring, thus increasing further the ability of this amino acid to act as an alkaloid precursor (see page 359). Tryptamine and its N-methyl and N,N-dimethyl derivatives...

Restoring Meth Alkaloid

Effects Marijuana Metabolism

Kreysigia multiflora (Liliaceae Convallariaceae). (S )-Autumnaline has also been found to act as a precursor for colchicine (Figure 6.66), an alkaloid containing an unusual tropolone ring. Colchicine is found in species of Colchicum*, e.g. Colchicum autumnale (Liliaceae Colchicaceae), as well as many other plants in the Liliaceae. Colchicine no longer has its nitrogen atom in a ring system, and extensive reorganization of the autumnaline structure is thus necessary. The seven-membered tropolone...

Purine Alkaloids

The purine derivatives caffeine*, theobromine*, and theophylline* (Figure 6.135) are usually referred to as purine alkaloids. As alkaloids they have a limited distribution, but their origins are very closely linked with those of the purine bases adenine and guanine, fundamental components of nucleosides, nucleotides, and the nucleic acids. Caffeine, in the form of beverages such as tea*, coffee*, and cola* is one of the most widely consumed and socially accepted natural stimulants. It is also...

Alkaloids

Alkaloids are classified according to the amino acid that provides both the nitrogen atom and the fundamental portion of the alkaloid skeleton, and these are discussed in turn. Ornithine gives rise to pyrrolidine and tropane alkaloids, lysine to piperidine, quinolizidine, and indolizidine alkaloids, and nicotinic acid to pyridine alkaloids. Tyrosine produces phenylethylamines and simple tetrahydroisoquinoline alkaloids, but also many others in which phenolic oxidative coupling plays an...

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Curare is the arrow poison of the South American Indians, and it may contain as many as 30 different plant ingredients, which may vary widely from tribe to tribe according to local custom. Curare is prepared in the rain forests of the Amazon and Orinoco, and represents the crude dried extract from the bark and stems of various plants. The young bark is scraped off, pounded, and the fibrous mass percolated with water in a leaf funnel. The liquor so obtained is then concentrated by evaporation...