Collect. Czech. Chem. Commun.
2002, 67, 645-664
https://doi.org/10.1135/cccc20020645
Reactivity of [1]Benzothieno[3,2-b][1]benzothiophene - Electrophilic and Metallation Reactions
Bedřich Košata, Václav Kozmík and Jiří Svoboda*
Department of Organic Chemistry, Institute of Chemical Technology, Prague, 166 28 Prague 6, Czech Republic
Abstract
Electrophilic nitration, formylation and acetylation of the title heterocycle 1 were studied. Monosubstitution proceeds preferentially in position 2 and to a lesser extent in position 4. Lowering the reaction temperature substantially increases regioselectivity of nitration and acetylation. Substitution reactions of the 2-substituted derivatives of 1 led to the corresponding 2,7-disubstituted derivatives as major products. Formation of other regioisomers was also observed. Metallation of 1 with butyllithium preferably proceeds in position 1; subsequent reaction with N,N-dimethylformamide, carbon dioxide or iodine gives rise to corresponding 1-substituted derivatives. Long-chain 2,7-disubstitued derivatives exhibit liquid-crystalline properties.
Keywords: [1]Benzothieno[3,2-b][1]benzothiophene; Electrophilic substitution; Nitration; Formylation; Acetylation; Regioselectivity; Metallation; Liquid crystals.
References: 22 live references.
