Alkaloids derived from anthranilic acid

Distribution of Pyrroloquinazoline Alkaloids Biological Activity Quinazolinocarboline Alkaloids Quinoline, Furoquinoline, Acridone, and 4-Quinoline Alkaloids 

Anthranilic acid (1) is an intermediate in the biosynthesis of tryptophan (see Chapter 7) (Fig. 31.1). A number of alkaloids, best known from the family Rutaceae, are biosynthesized from this important primary compound. 

Small amounts of A-methylanthranilate occur in a number of essential oils (Groger, 1980). Another simple representative, damascenine (2), is found in the seeds of Nigella damascena L. (Ranunculaceae) (Fig. 31.2). This alkaloid has been shown to come from shikimic acid via anthranilic acid (Cordell, 1981). [ CHsl-Methionine is an efficient precursor of all three bound methyl groups (Groger, 1980 Geiss-man and Crout, 1969). 

Dianthalexin (4) and related 7V-benzoylanthranilic acid derivatives are formed in response to fungal attack in Dian-thus (Caryophylaceae) (Ponchet et al., 1984). 

Other compounds apparently are derived from 3-hydrox-yanthranilic acid (3), for example, several compounds from Tecoma starts (Bignoniaceae), are catabolic products of tryptophan (Groger, 1980 Geissman and Crout, 1969). 3-Hy-droxyanthranilic acid is involved in the biosynthesis of several fungal pigments and in actinomycins from strains of Streptomyces. Actinomycin A was isolated soon after penicillin, but it was too toxic for general use. Actinomycin D 

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The route of formation of the carbazole nucleus is still far from understood, and has been variously considered to arise from 3-prenylquinolone via a pathway involving shikimic acid (394) and mevalonic acid (MVA) (400) (Scheme 3.1) (1,112,362-366), anthranilic acid (397) and prephenic acid (404) via a pathway involving shikimic acid (394) (Scheme 3.2) (367), and also tryptophan (408) involving the mevalonate (400) pathway (Scheme 3.3) (133). All of these pathways lack experimental proof. However, based on the occurrence of the diverse carbazole alkaloids derived from anthranilic acid (397) in the family Rutaceae, the pathway... 

This approach though also has some complications, particularly when the alkaloid has more than one nitrogen and more than one biosynthetic amino acid precursor unit. For example, evodiamine and rutaecarpine, from the fruits of Euodia mtaecarpa (Rutaceae), can be classified as alkaloids derived from tryptophan. In addition, one of the nitrogen atoms of each alkaloid is derived from an anthranihc acid unit. Therefore, these alkaloids can be classified as alkaloids derived fiom tryptophan and as alkaloids derived from anthranilic acid. In this volume, these alkaloids are discussed in Chapter 2.19 as alkaloids derived from tryptophan. 

In the biosynthetic pathway of the alkaloids derived from anthranilic acid, the carbon atom corresponding to the carboxyl carbonyl group is included in the resulting alkaloids, except for those alkaloids with the phen-azine skeleton. The main groups of alkaloids derived from anthranilic acid are classified as quinoline, acridone, and quinazoline alkaloids. These alkaloids are typically isolated from rutaceous plants, except for febrifugine and related alkaloids, which possess the quinazoline skeleton these are isolated from plants of the Saxifragaceae family. 

Both the H- and C-NMR (nuclear magnetic resonance) spectra and techniques for the isolation and characterization of several groups of alkaloids derived from anthranilic acid have been reviewed (Crabb, 1982 Gray, 1993). The results of feeding studies leading to several alkaloids derived from anthranilic acid have been tabulated (Leete, 1983). 

Alkaloids Derived from Anthranilic Acid O OCH3... 

Groger, D. Alkaloids derived from tryptophan and anthranilic acid. In Encyclopedia of Plant Physiology, New Series, Vol. 8, Secondary Plant Products (E. A. Bell, B. V. Charlwood, eds.), pp. 128-159. Springer, Berlin-Heidelberg-New York 1980 Johne, S., Groger, D. Natiirlich vorkommende Chinazolin-Derivate. Pharmazie 25, 22-44 (1970) Luckner, M., Johne, S. Alkaloids derived from anthranilic acid. In Biochemistry of Alkaloids (K. Mothes, H. R. Schiitte, M. Luckner, eds.), Deutscher Verlag der Wissenschaften, Berlin 1985... 

Luckner, M., Johne, S. Alkaloids derived from anthranilic acid. In Biochemistry of Alkaloids (K. Mothes, H. R. Schiitte, M. Luckner, eds.). VEB Deutscher Verlag der Wissenschaften, Berlin 1985... 

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