Collect. Czech. Chem. Commun.
2004, 69, 1631-1642
https://doi.org/10.1135/cccc20041631
Rearrangement of Substituted 2,4,4,6-Tetraaryl-4H-thiopyrans to Triaryl-3aH-benzo[3,4]cyclopenta[1,2-b]thiophene
Jiří Kroulíka,*, Jan Čejkab, Petr Sedmerac, Alexandr Jegorovd, Bohumil Kratochvílb and Josef Kuthana
a Department of Organic Chemistry, Institute of Chemical Technology, Prague, 166 28 Prague 6, Czech Republic
b Department of Solid State Chemistry, Institute of Chemical Technology, Prague, 166 28 Prague 6, Czech Republic
c Institute of Microbiology, Academy of Sciences of the Czech Republic, 142 20 Prague 4, Czech Republic
d IVAX-CR., Research Unit, Branišovská 31, 370 05 České Budějovice, Czech Republic
Abstract
An intensive bromination of 2,6-diaryl-4,4-diphenyl-4H-thiopyrans can lead through 3,5-dibromo derivatives to unexpected 2,8-diaryl-3-bromo- and 2,8-diaryl-3,5-dibromo-3a-phenyl-3aH-benzo[3,4]cyclopenta[1,2-b]thiophene as demonstrated on examples where the respective aryl groups are phenyl or 4-fluorophenyl. On the other hand, analogous spiro- [fluorene-9,4'-thiopyran]s do not exhibit the rearrangement evidently due to a rigid conformation of the fluorene moiety. The reaction mechanism for the rearrangement is proposed.
Keywords: Thiopyrans; Bromination; Benzo[3,4]cyclopenta[1,2-b]thiophene; Thiapentalene; Rearrangements; Sulfur heterocycles.
References: 22 live references.
