Synlett 2001; 2001(9): 1383-1386
DOI: 10.1055/s-2001-16795
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Synthesis of Cycloalka[a]- and Cycloalka[c]phenanthrene Aminonitriles from 2-(1-Naphtyl)cycloalkylidene Malonodinitriles Involving Novel Aromatic Rearrangement

Janusz J. Sepiol* , Maciej Gora, Michal K. Luczynski
  • *Department of Organic Chemistry, Jagiellonian University, Ingardena 3, PL 30-060 Krakow, Poland; Fax + 48-12-6 34 05 15; E-mail: sepiol@chemia.uj.edu.pl
Further Information

Publication History

Publication Date:
28 August 2001 (online)

Cyclization of 2-(1-naphthyl)cyclopentylidene malonodinitrile (2a) in polyphosphoric acid (PPA) affords 5-amino-2,3-dihydro-1H-cyclopenta[c]phenanthrene-4-carbonitrile (4a), a product of straightforward cyclization, and 11-amino-16,17-dihydro-15H-cyclopenta[a]phenanthrene-12-carbonitrile (3a), which appears to result through rearrangement of the carbon framework of 2a. Ring closure of 2-(1-naphthyl)cyclohexylidenemalonodinitrile (2b) or ethyl 2-(1-naphthyl)cyclopentylidenecyanoacetate (2c) in concentrated sulfuric acid or PPA give nearly exclusively the following rearranged products: 5-amino-7,8,9,10-tetrahydrochrysene-6-carbonitrile (3b) or ethyl 11-amino-16,17-dihydro-15H-cyclopenta[a]phenanthrene-12-carboxylate (3c), respectively. Aminonitriles 3a and 4a are obtained as an easily separable mixture in 58 : 42 ratio. A suggested mechanism of this new aromatic rearrangement is presented.

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