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

• interface temperature was set at 180 °C. 2-(Dialkylamino)naphthoquinones 3 were prepared as described [24]. 2-(Dialkylamino)anthracene-1,4-diones 4 were prepared from anthracene-1,4-dione by a similar procedure [25]. General procedure for the synthesis of 3-methyl-2,3-dihydronaphtho[2,3-d][1,3]thiazole-4,9

• a solution of the appropriate 2-(dialkylamino)naphthoquinone 3 or 2-(dialkylamino)anthracene-1,4-dione 4 (1.00 mmol) in chlorobenzene (40 mL) was added at −30 °C. The reaction mixture was stirred for 0.5 h at −20 °C, and triethylamine (1.4 mL, 10 mmol) was added at this temperature. The reaction

• )anthracene-1,4-diones 4, sulfur monochloride and Hünig’s base: Sulfur monochloride (0.72 mL, 9.00 mmol) was added dropwise to a stirred solution of the appropriate 2-(dialkylamino)anthracene-1,4-dione 4 (1.00 mmol) and N-ethyldiisopropylamine (0.86 mL, 5.00 mmol) in tetrahydrofurane (65 mL) under argon at

Functionalization of anthracene: A selective route to brominated 1,4-anthraquinones

• Kiymet Berkil Akar,
• Osman Cakmak,
• Orhan Büyükgüngör and
• Ertan Sahin

Beilstein J. Org. Chem. 2011, 7, 1036–1045, doi:10.3762/bjoc.7.118

• derivatives that are difficult to prepare by other routes. The studies also reveal the broad range of reactivity and selectivity of the stereoisomeric anthracene derivatives. Keywords: anthracene derivatives; anthracene-1,4-dione; aromatization; bromination; bromoanthracene; methoxyanthracene; silver-induced

• constitute potentially important keys for the synthesis of pharmaceutical chemicals [4][5][6][7], natural products [8][9] and donor properties [10][11]. Anthraquinone 28 may be used as precursor for 9,10-disubstituted-2-phenoxy-anthracene-1,4-dione derivatives that are difficult to synthesize by other routes

• the structure of the compound. It is clear that 1,4-diol 27 should be easily converted to anthracene-1,4-dione 28. Thus, compound 27 was made to react with PCC at room temperature for 3 days. After the reaction, a simple short silica gel filtration and crystallization from CH2Cl2, gave the expected