Diels-alder reaction with cyclic sulfones. 9.* Synthesis of 10-oxo-1h-tetrahydrofluo-reno[2,1-b]thiophene dioxides*2 |
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Authors: | E E Shults G N Andreev M M Shakirov I Yu Bagryanskaya G A Tolstikov |
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Institution: | (1) N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia;(2) M. K. Ammosov Yakutsk State University, Yakutsk, 677000, Russia |
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Abstract: | The treatment of 5-aryl-4′,6′-dioxo-2,3,3a,4,5,6-hexahydrospiro-benzothiophene-4,5′-1,3-dioxane] 1,1-dioxides with boron
trifluoride etherate in dichloroethane leads to the formation of products of intramolecular acylation, namely, the corresponding
10-oxo-1H-5,5a,10a,10b-tetrahydrofluoreno-2,1-b]thiophene dioxides. In all cases, 5-aryl-4-carboxyhexahydrobenzob]thiophene 1,1-dioxides were also isolated. The product ratio depends on the structure of the aromatic substituent at C(5)
of the spiro- adducts. The structure of 4-carboxy-5-(2-methoxyphenyl)-7-methyl -2,3,3a,4,5,6-hexahydro-benzob]thiophene 1,1-dioxide was confirmed by X-ray diffraction structural analysis.
*For Communication 9 see 1].
*2Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1503–1512, October, 2008. |
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Keywords: | benzo[b]thiophene dioxides fluoreno[2 1-b]thiophene dioxides intramolecular Friedel-Crafts acylation Diels-Alder reaction |
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