Antitumour Heterocycles. Part 16.1 The Synthesis of 7,10-Dimethoxyellipticine and its Pyrrolo[2,3-f]carbazole and Pyrrolo[3,2-f] Analogues

Abstract

The final examples in our ellipticine/pyrrolocarbazole synthesis programme are 7,10-dimethoxyellipticine 1a and the corresponding pyrrolocarbazoles 2a and 3a which have been synthesised from 4,6-dimethoxyindole.

Isolation and Synthesis of Biologically Active Carbazole Alkaloids

“…883 In 1997, Shannon and his group observed the formation of a N-C3-linked dimer during the transformation of a 3-bromocarbazole to a 3-cyanocarbazole by reaction with copper(I) cyanide in N,N-dimethylformamide under reflux. 884 However, this procedure was not applied to the synthesis of naturally occurring dimeric carbazoles. Additional total syntheses of dimeric carbazole alkaloids are described in section XI.6.…”

“…Furukawa and co-workers obtained a mixture of murrafoline-D ( 1230 ), -G ( 1231 ), and -H ( 1232 ) (see Scheme ) by refluxing a solution of murrayafoline-A ( 2 ) and girinimbine ( 458 ) in aqueous methanol for 27 h in the presence of ion-exchange resin (Nafion 117). , Chakrabarti and Chakraborty described the reaction of girinimbine ( 458 ) with BF 3 etherate in dichloromethane at room temperature, which afforded murrafoline-H ( 1232 ) in 21% yield . In 1997, Shannon and his group observed the formation of a N−C3-linked dimer during the transformation of a 3-bromocarbazole to a 3-cyanocarbazole by reaction with copper(I) cyanide in N , N -dimethylformamide under reflux . However, this procedure was not applied to the synthesis of naturally occurring dimeric carbazoles.…”

A General and Efficient Copper Catalyst for the Amidation of Aryl Halides

“…Both the Ullmann reaction (copper-catalyzed N -arylation of amines) and the related Goldberg reaction (copper-catalyzed N -arylation of amides) predate the palladium-catalyzed amination methodology by many decades. While applications of the Ullmann and Goldberg reactions in academic and industrial laboratories are well-documented, the methods have remained relatively undeveloped.…”

Synthesis of Highly Substituted Diphenylacetamides and Diphenylsulfonamides by the Goldberg Coupling Reaction

“…In a preliminary paper on the Goldberg coupling reaction of aryl halides with amides, the effect of a variety of substituents in the reactants was investigated and it was shown that the yields are markedly susceptible to the presence of electron withdrawing groups in both reactants. 1 The effect of substituent methyl groups on the reaction yield was not investigated but this could be important if the products such as 1 or 2 were to be used for the synthesis of 1,4dimethylcarbazoles 3 (Scheme 1) as precursors of ellipticines. Until now, carbazoles have been fruitful precursors of ellipticines.…”

“…We now report the synthesis of a series of multisubstituted diphenylacetamides 1 and diphenylsulfonamides 2 which embody 2,5-dimethyl substituents, thus extending our earlier work. 1 The diphenylacetamides (1a-f) were prepared by Goldberg coupling, as shown in the Table 1. The different effect of substituents in the coupling components on the yields obtained is noteworthy (16-81%).…”