Indolo carbazole alkylation

The indol-3-yl-substituted indolo[2,3-()]carbazole 143 has been isolated as a product from the complex mixture generated by the decomposition of urorosein (144) (99CHE561). Interestingly, when subjected to alkylation conditions involving sodium hydride and dimethyl sulfate in THF, 143 was transformed into the N. -dimethyl derivative 145 in 36% yield (00MI2). 

In an effort toward indolo[3,2-h]carbazoles based on Lewis acid-assisted dimerization of benzotriazole derivatives, the necessary starting materials 197 were prepared in good yields from 1-propargylbenzotriazole and 2-iodoaniline followed by alkylation. In the ensuing dimerization step, compounds 197 were treated with zinc chloride in refluxing dichlorometane to afford the indolo[3,2-h]carbazoles 199 or the dihydro derivatives 198 (Scheme 27). Under similar conditions 197, where R = = H, did not undergo dimerization, which suggests that the alkyl... 

All the substituted indolo[3,2-b]carbazoles (5) with long alkyl side-chains form highly crystalline thin films on vacuum deposition. The X-ray diffraction patterns of the thin films, deposited at respective optimum substrate temperatures, give sharp and intense crystalline diffraction peaks (Fig. 4.13). Table 4.2 summarizes the XRD data and extracted interlayer distances of molecular orders of indolo[3,2-h]carbazoles in crystalline thin films. Only 5e, which has no long alkyl chain, has broad XRD diffraction peaks indicative of its amorphous nature. These results... 

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