Synthesis of 2,3-dihydronaphtho[2,3-d][1,3]thiazole-4,9-diones and 2,3-dihydroanthra[2,3-d][1,3]thiazole-4,11-diones and novel ring contraction and fusion reaction of 3H-spiro[1,3-thiazole-2,1'-cyclohexanes] into 2,3,4,5-tetrahydro-1H-carbazole-6,11-diones

• Lidia S. Konstantinova,
• Kirill A. Lysov,
• Ljudmila I. Souvorova and
• Oleg A. Rakitin

Beilstein J. Org. Chem. 2013, 9, 577–584, doi:10.3762/bjoc.9.62

• ., ring contraction and fusion products. A plausible mechanism was proposed for the formation of the products. Keywords: anthracene-1,4-diones; 1H-carbazole-6,11-diones; fused thiazoles; fusion reaction; heterocycles; naphthoquinones; ring contraction; sulfur–nitrogen; Introduction The 1,4

• this paper we report a study of a reaction between dialkylaminonaphtho- and anthraquinones and sulfur monochloride in the presence of tertiary amines, a selective synthesis of fused thiazoles, and some of their chemical transformations. Results and Discussion We examined in detail the reaction of 2

• observations. Further on, we extended this reaction to other naphthoquinones 3. Fused thiazoles 1 were obtained with yields from moderate to high. NMR spectroscopy of thiazoles 1 showed that in all the cases either the primary, secondary or tertiary carbon atom attached to the nitrogen atom was included in the