Synthesis of 3,4,5,6-tetrahydrobenzo[c]phenanthridin-3-ones

✍ Scribed by A. N. Pyrko

• Book ID: 104781703
• Publisher: Springer US
• Year: 1990
• Tongue: English
• Weight: 133 KB
• Volume: 26
• Category: Article
• ISSN: 0009-3122
• DOI: 10.1007/bf00473978

✦ Synopsis

In 1971, the synthesis was reported of the tetrahydrobenzacridine (V), which was originally assigned the tetrahydrobenzo[c]phenanthridine structure (Ia). The erroneous nature of the structure assigned was shown by Cortes et al. [2] on the basis of x-ray diffraction data.

We have synthesized compounds (Ia, b) by intramolecular cyclization of the enaminoketones flla, b), obtained from ~xnaphthylamine ( 111) and the [~-triketones OVa, b).

5,5-Dimethyl-2.[ct-(2-naphthylaminobenzylidene]cyclohexane.l,3.dione (IIa). A mixture of 2.44 g (10 mmoles) of benzoyldimedone and 1.43 g (10 mmoles) of a-naphthylamine in 60 ml of toluene was boiled for 2 h with a Dean and Stark attachment. The toluene was evaporated, and the residue crystallized from 20 ml of ethyl acetate to give 3.33 g (90%/of the enaminodiketone (IIa), mp 202-202~ IR spectrum (KBr): 1536 (C--C); 1580, 1658 (C=O); 3440 cm -1 (NH). PMR spectrum (CDC13): 15.05 (1H, s, NH); 8.10 (1H, d, J --7.5 Hz, 8"-I-I); 7.70-6.90 (9H, m, arom.); 6.74 (1H, d, J = 7.3 Hz, 2"-H); 2.64 and 2.38 (2H each, s, CH2); 1.16 ppm (6H, s, 2CH3). M + 369.