Syntheses Based on Naphthalene Derivatives

The heterocyclization of peri-aminonaphthoyl compounds allows the preparation of three main types of benzo[crf]indole series, namely, bases 113, benzo[crf]indolium salts 114, and benzo[crf)indole-2-ones 115. Because closure to the nitrogen heterocycle is so facile, peri-amino-substituted naphthaldehydes and naphthyl ketones, even under conditions of their formation, are converted into benzo[crf]indoles 113. Those unsubstituted in position 2, as well as 2-alkyl-substituted benzo[cd]indoles 113 (R = H, Aik), have not been isolated because of their easy oxidation by air. 

8-Amino-4-methoxy-l-methoxymethylnaphthalene 120, obtained from the chloromethyl derivative 111, is transformed into azide 121. The latter undergoes photolytic heterocyclization to the labile 5-methoxyben-zo[cd]indole 117 which, on reduction by lithium aluminium hydride followed by acetylation, is converted into the stable l-acetyI-5-methoxy-l, 2-dihydrobenzo[o/]indole 119 (R = OMe) [71JCS(C)721]. The reduction of methyl or phenyl 8-nitro-1 -naphthyl ketones by hydrogen and platinum dioxide or by iron in acetic acid leads to a mixture of products (59M634). 

on heating perchlorates of 5-alkoxy-l-aminonaphthalene 125 (R = Me, Et) with alkyl carboxylic anhydrides in the presence of catalytic ammounts of perchloric acid, N-protonated 2-alkyl-benzo[cd]indolium 

The method just described allows high yields of the various N-protonated, N-alkylated, and N-acylated benzo[cd]indolium salts, both 

The course of reaction and the character of the final products are determined by electronic effects of substituents at the aryl ring (Ar) of N-protonated azomethine 130. The most interesting is the reaction leading to 2-styrylbenzo[crf]indolium salts 132 the formation of which can be represented as the result of a rearrangement of intermediate 134. The latter is afforded by C-acylation of azomethine perchlorate 130. 

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