W. Krasodomski, Michał Łuczyński, J. Wilamowski
Jul 21, 2003
Citations
0
Influential Citations
10
Citations
Journal
Tetrahedron
Abstract
Abstract The study has been carried out to evaluate the feasibility of synthesis of 1-methyl-, 2-methyl-, 1,2-dimethyl-, and 1-ethyl-2-methylphenanthrene through the annulation of the naphthalene system with the exploitation of the dicyanovinyl moiety of 2-naphthylalkylidenemalonodinitriles as an active electrophile in cold solutions of concentrated sulfuric acid. 2-(2-Naphthyl)propanal ( 3 ), 1-(2-naphthyl)propan-2-one ( 9 ), 3-(2-naphthyl)butan-2-one ( 14 ), and 3-(2-naphthyl)pentan-2-one ( 19 ) had been condensed with malonodinitrile to afford 2-naphthylalkylidenemalonodinitriles which were then cyclised to give 4-amino-1-methylphenanthrene-3-carbonitrile ( 5 ), 4-amino-2-methylphenanthrene-3-carbonitrile ( 11 ), 4-amino-1,2-dimethylphenanthrene-3-carbonitrile ( 16 ), and 4-amino-1-ethyl-2-metylphenanthrene-3-carbonitrile ( 21 ). The nitrile function has been removed from the aminonitriles, with the exception of 21 , through hydrolysis and decarboxylation in alkaline ethanolic solutions under elevated pressure (∼3 MPa) and temperature 220–230°C to give the respective 4-amino-methylphenanthrenes. Diazotisation of the phenanthreneamines and the reaction with hypophosphorus acid has lead to the methylphenanthrenes in moderate yields (50–52%).