ChemInform Abstract: SYNTHESIS OF SOME BENZOPYRANO‐ AND THIOPYRANOAZOLES

Synthesis of Triazolo[c]coumarins and Differences in the Fluorescence Properties of Their Isomers

“…were stirred at 120 °C under neat condition for 8 h. The reaction mixture was directly purified by flash column chromatography (Diol-silica gel: 10 g, 5% AcOEt/hexane) to afford anti-5 as a yellow green oil (108.0 mg, 0.207 mmol, 79%) and syn-5 as a white solid (26.2 mg, 50.1 μmol, 19%). anti-5: 1 H-NMR (400 MHz, CDCl 3 ) δ = 7.22-7.16 (overlapped, 3H), 6.96-6.92 (overlapped, 2H), 6.66 (d, J = 8.8 Hz, 1H), 6.28 (dd, J = 8.8, 2.4 Hz, 1H), 6.16 (d, J = 2.4 Hz, 1H), 4.55 (ddd, J = 13.6, 8.0, 6.0 Hz, 1H), 4.36-4.24 (overlapped, 3H), 3.36 (m, 4H), 3.09 (m, 2H), 1.28 (t, J = 7.2 Hz, 3H), 1.20 (t, J = 7.0 Hz, 6H), 0.74 (s, 9H), 0.10 (s, 3H), À 0.13 ppm (s, 3H); 13 4.88 (t, J = 8.2 Hz, 1H), 4.22 (q, J = 7.2 Hz, 2H), 3.35 (q, J = 7.1 Hz, 4H), 3.22 (dd, J = 10.8, 5.6 Hz, 1H), 3.22 (t, J = 8.2 Hz, 1H), 1.18 (t, J = 7.0 Hz, 6H), 1.17 (t, J = 7.0 Hz, 3H), 0.77 (s, 9H), À 0.04 ppm (s, 6H); 13 C-NMR (100 MHz, CDCl 3 ) δ = 159.9, 154. 5…”

“…m.p. 129.3-130.5 °C; 1 H-NMR (400 MHz, CDCl 3 ) δ = 7.25-7.19 (overlapped, 3H), 7.04-7.02 (overlapped, 2H), 6.79 (s, 1H), 6.67 (d, J = 8.4 Hz, 1H), 6.36 (d, J = 2.4 Hz, 1H), 6.32 (dd, J = 8.8, 2.4 Hz, 1H), 4.47 (t, J = 7.6 Hz, 2H), 4.42 (q, J = 7.1 Hz, 2H), 3.38 (q, J = 7.1 Hz, 4H), 3.14 (m, 2H), 1.39 (t, J = 7.2 Hz, 3H), 1.20 (t, J = 7.0 Hz, 6H); 13 C-NMR (100 MHz, CDCl 3 ) δ = 163.5, 155.8, 150.9, 139.0, 137.0, 136.7, 131.4, 128.7 (2 C), 128.7 (2 C), 126.9, 105.0, 101.1, 100.0, 61.9, 49.9, 44.9 (2 C), 35.9, 14.1, 12.5 ppm (2 C); IR (NaCl plate) ν = 3169 (br, OH), 1725 (s, C=O), 1622 (vs, N-Ar) cm À 1 ; MS (EI) m/z (%): 408 (67) [M] + , 393 (6), 363 (11), 244 (16), 105 (16); HRMS (EI) m/z calcd. for C 23 H 28 N 4 O 3 : 408.2161 [M] + , found: 408.2162.…”

“…m.p. 97.0-97.8 °C; 1 H-NMR (400 MHz, CDCl 3 ) δ = 10.5 (s, 1H), 7.64 (d, J = 8.8 Hz, 1H), 7.33-7.23 (overlapped, 3H), 7.18-7.16 (overlapped, 2H), 6.32 (d, J = 2.8 Hz, 1H), 6.24 (dd, J = 9.2, 2.8 Hz, 1H), 4.92 (dd, J = 9.0, 6.2 Hz, 1H), 4.92 (t, J = 7.6 Hz, 1H), 4.38 (q, J = 7.2 Hz, 2H), 3.76 (q, J = 7.1 Hz, 4H), 3.21 (m, 2H), 1.39 (t, J = 7.2 Hz, 3H), 1.19 ppm (t, J = 7.0 Hz, 6H); 13…”

“…m.p. 134.5-135.0 °C; 1 H-NMR (400 MHz, CDCl 3 ) δ = 7.55 (m, 1H), 7.34-7.18 (overlapped, 5H), 6.65 (m, 2H), 4.93 (m, 2H), 3.44 (q, J = 7.2 Hz, 4H), 3.32 (m, 2H), 1.23 ppm (t, J = 7.0 Hz, 6H); 13…”

“…The synthesis of 3,4-triazole-fused coumarin (triazolo[c]coumarin) has been reported using seven synthetic methods. [7][8][9][10][11][12][13] What they have in common is a synthetic approach that leads to triazolo[c]coumarin after construction of the coumarin skeleton. We hypothesized that the Huisgen cycloaddition could be exploited by lactonization at the end.…”