Heterocyclic Systems with Heteroatoms of the Same Name

Heterocyclic Systems with Heteroatoms of the Same Name 

2- heteroatoms of chalcogenes (S, Se, Te) are interesting because of the augmented 7r-donor properties, and because of this fact, these compounds are used in studies of metal conductivity ( organic metals ). Such substances are deeply colored, which is explained by the high delocalization of the ip-electrons of an X—X group and formation of the 7r-system common with the naphthalene nucleus. 

There are two general approaches to constructing the five-membered 

Following interaction between lithiated naphthalene derivatives and chalcogene, heteroring closure requires the participation of an oxidant. In this case, oxygen of the air may play such a role. On air oxidation, 1,8-dithionaphthol is converted into naphtho[a/]dithiol 216 (65JOC3997). 

Heating 1,8-dichloroanthraquinone with sodium disulfide or diselenide in dimethylformamide (DMF) leads to pentacyclic systems 217 [78IJC(B)673]. The formation of heterocyclic systems of type 217 and 

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