Ellipticine alkaloids antitumor activity

The strong interest in the synthesis of pyrido[4,3-h]carbazole alkaloids started in the late 1960s with the disclosure of the antitumor activity of ellipticine (228) and 9-methoxyellipticine (229) (see Scheme 2.56) in several animal and human tumor systems. This discovery made these alkaloids to important synthetic targets and induced extensive studies of structure modification. These synthetic efforts have... 

Among the carbazole alkaloids the most noteworthy is ellipticine (28). It and a number of synthetic analogs exhibit significant antitumor activity. The mechanism of action is believed to involve interaction with DNA (79MI30602). 

SYNTHESIS AND ANTITUMOR ACTIVITY OF ELLIPTICINE ALKALOIDS AND RELATED COMPOUNDS... 

Ellipticine alkaloids and related compounds synthesis and antitumor activity of, 39, 239 (1990)... 

Chapter 7. Synthesis and Antitumor Activity of the Ellipticine Alkaloids and Related Compounds... 

The antitumor activity of these alkaloids has led to renewed interest in their synthesis. Saxton s synthesis of ellipticine (CCXCVI Volume VIII, pp. 477-480), the most adaptable to large-scale production, has been shortened by two steps by the direct cyclization of the intermediate (CCXCVII) in 90-100% phosphoric acid. The same route has been used to synthesize 9-methoxyellipticine (CCXCIX) from 5-methoxyindole (CCXCVIII) 88). This alkaloid, earlier thought to be 8-methoxy-ellipticine (CCC) on the basis of UV- and fluorescence-spectra 47), is identical with the methoxyellipticine referred to in Volume VIII. 

Gribble, G. W., Synthesis and antitumor activity of ellipticine alkaloids and related compounds, in The Alkaloids, Vol. 39 (A. Brossi, ed.), 239-352, Academic Press, New York, 1990. 

Ellipticine (E) 1 is an indolic alkaloid with antitumor activity. Some of its phenolic derivatives as N-methyl-9-hydroxyellipticine (Celiptinium), obtained from 9-hydroxy ellipticine (9-OH E), exhibit high cytotoxicity. 38 Syntheses of 9-OH E are not satisfactory considering yields and cost, justifying the attempts at the direct conversion of E to 9-OH E via 9-oxoellipticine (9-0X0 E). Potassium nitrosodisulfonate (Fremy s salt), a valuable oxidant for the synthesis of quinone-imine from heterocyclic amines,139 was used. Under these conditions the conversion of E to 9-0X0 E was observed for the first time. Its reduction to 9-OH E is then easily achieved with ascorbic acid. The radical nature of Fremy s salt [ 0-N(S03K)2] led us to carry out the oxidation reaction under sonication in order to increase the yields via an easier electron transfer.1 1... 

The antitumor alkaloid ellipticine (5,1 l-dimethyl-6//-pyrido[4,3-b]carbazole) has been isolated from many species of Ochrosia and Aspidosperma. Ellipticine and its derivatives are highly active versus several experimental neoplasms, and the compound has been widely subjected to studies devoted to its total synthesis, the preparation of derivatives, and metabolism. Metabolic transformation studies with ellipticines have been conducted, using microorganisms, in vivo and in vitro... 

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