Thiophen Analogues of Polycyclic Hydrocarbons

Miscellaneous Thiophen Analogues of Polycyclic Hydrocarbons.—Starting from compound (513), the annelated acenaphthylene (514) and derivatives thereof were prepared via condensation with ethyl thioglycollate. The analogous c-annelated system (515) was obtained by the reaction of (516a) 

Treatment of phenanthrene with hydrogen sulphide and an alumina catalyst at 630 °C gives the compound (517). Its spectral properties and those of its sulphoxide and sulphone were discussed. Other examples of the direct insertion of a sulphur bridging atom into an aromatic molecule are reviewed. 

Bastian, A. Ebnother, and E. Jucker, Helv. Chim. Acta, 1971, 54, 283. 

In connection with work on the synthesis of the sulphur isostere of lysergic acid, a number of derivatives of naphtho[l,8-Ac]thiophen (518) have been prepared. The ketone (519) is noticeably basic and dissolves in concentrated hydrochloric acid, presumably forming the aromatic ion (520).  

Three phenalenothiophens (521)—(523) have been synthesized by unambiguous methods from the corresponding phenalenothiophenones (524)— (526), which in turn were prepared by electrophilic ring-closure of the corresponding 3-(a-naphthyl)thiophen-2-carboxylic acid, 2-(a-naphthyl)-thiophen-3-carboxylic acid, and 3-(a-naphthyl)thiophen-4-carboxylic acid. The reaction of (527) with glycerol, sulphuric acid, and iron leads to the 

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