Synthesis of alkylphenanthrenes from naphthylalkylidenemalonodinitriles. A route to 1-methyl-, 2-methyl-, and 1,2-dimethylphenanthrene

✍ Scribed by Wojciech Krasodomski; Michał K Łuczyński; Jarosław Wilamowski; Janusz J Sepioł

• Book ID: 104205521
• Publisher: Elsevier Science
• Year: 2003
• Tongue: French
• Weight: 173 KB
• Volume: 59
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(03)00884-6

✦ Synopsis

The study has been carried out to evaluate the feasibility of synthesis of 1-methyl-, 2-methyl-, 1,2-dimethyl-, and 1-ethyl-2methylphenanthrene 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. 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-3carbonitrile (5), 4-amino-2-methylphenanthrene-3-carbonitrile (11), 4-amino-1,2-dimethylphenanthrene-3-carbonitrile ( 16), and 4-amino-1ethyl-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 220-2308C 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%).