Dicyclohepta[cd,gh]pentalene—A New Pyrene Isomer

✍ Scribed by Dr. Henning Reel; Prof. Dr. Emanuel Vogel

• Publisher: John Wiley and Sons
• Year: 1972
• Tongue: English
• Weight: 261 KB
• Volume: 11
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.197210131

✦ Synopsis

152-155"C, which is recyclized to (3a) by phosgene in the presence of a tertiary amine. 3,4-Dichloroaniline reacts with (3a) even at ca. 20"C, giving the monothiotriuret (6a), m.p. 163°C. (3a) can be prepared from (la) and phenoxycarbonyl isocyanate in boiling toluene even in absence of a tertiary base.

Experimental :

A solution of (la) (11.6 g, 0.1 mol) in methylene chloride (40 ml) is added, with cooling, to one of N-chlorocarbonyl isocyanate (10.5 g, 0.1 mol) in methylene chloride (60 ml). The white precipitate of (2a) that is immediately formed is filtered off and dried. M. p. 222°C. Yield 19.5 g (95%).

A solution of (2a) (22.15 g, 0.1 mol) in water (50 ml) is added dropwise with cooling, to one of N,N-dimethylaniline (12.1 g, 0.1 mol) in methanol (50 ml). The white precipitate is filtered off and washed with water, giving 70% (13 g) of (3a), m.p. 21@-211"C.