Beilstein J. Org. Chem. 2013, 9, 2669–2674.
(d, 1H, J = 9.5 Hz, H-4), 7.77 (d, 1H, J = 9.5 Hz, H-5), 8.14 first extraction, precipitation of the product occurred between
(dd, 1H, J = 8.0, 1.4 Hz, H-6), 9.04 (dd, 1H, J = 4.4, 1.4 Hz, the organic and water phases due to its low solubility in ethyl
H-8); 13C NMR (75 MHz, CDCl3) δ 123.1, 124.0, 128.6, 130.6, acetate. In this case, the water phase was separated to leave the
136.0, 144.4, 150.1, 158.5, 160.7; anal. calcd for C9H5N3Se: C, precipitate in the organic phase in a separatory funnel. Methanol
46.17; H, 2.15; N, 17.95, found: C, 46.20; H, 2.14; N, 18.00.
(15 mL) was added to this suspension to dissolve the precipi-
tated product and the resulting yellow solution was put aside.
Pyrido[2,3-f]quinoxaline (8). Diimine 7 (113 mg, 0.51 mmol) The water phase was extracted with 5 additional portions of
was added to a stirred solution of hydrochloride 5 (100 mg, ethyl acetate. The combined organic phases were dried with
0.51 mmol) in MeOH (8 mL) and stirring was continued at Na2SO4, filtered and evaporated under reduced pressure to
room temperature for 1.5 h. The volatiles were evaporated afford 4-chlorodiaminoquinoline 11 (0.28 g, 77%) as a
under reduced pressure and the residue was purified by FLC yellow–brown solid which was characterised without further
(silica gel, CHCl3/MeOH 100:1, Rf = 0.25) to afford pyrido- purification; mp > 150 °C (dec.). 1H NMR (300 MHz, DMSO-
quinoxaline 8 (75 mg, 81%) as an off-white solid; mp d6) δ 5.13 (br s, 2H, NH2), 5.23 (br s, 2H, NH2), 7.27 (s, 2H,
147–149 °C (Ref. [16] mp 146.5–147.5 °C). 1H NMR (300 H-7, H-8), 7.28 (d, 1H, J = 4.5 Hz, H-3), 8.29 (d, 1H, J = 4.5
MHz, CDCl3) δ 7.69 (dd, 1H, J = 8.1, 4.3 Hz, H-8), 8.03 (d, 1H, Hz, H-2); 13C NMR (75 MHz, DMSO-d6) δ 114.8, 118.9,
J = 9.1 Hz, H-5), 8.08 (d, 1H, J = 9.1 Hz, H-6), 8.30 (dd, 1H, J 121.5, 121.6, 125.8, 132.8, 136.8, 144.52, 144.53; anal. calcd
= 8.1, 1.6 Hz, H-7), 9.01 (d, 1H, J = 1.9 Hz, H-3), 9.10 (d, 1H, J for C9H8ClN3: C, 55.83; H, 4.16; N, 21.70, found: C, 55.93; H,
= 1.9 Hz, H-2), 9.21 (dd, 1H, J = 4.3, 1.6 Hz, H-9); 13C NMR 4.12; N, 21.79.
(75 MHz, CDCl3) δ 123.6, 128.1, 128.4, 130.1, 136.1, 141.3,
144.4, 144.5, 145.5, 145.7, 150.7; anal. calcd for C11H7N3: C,
Supporting Information
72.92; H, 3.89; N, 23.19; found: C, 72.97; H, 3.90; N, 23.17.
Supporting Information File 1
9-Chloro-[1,2,5]selenadiazolo[3,4-f]quinoline (10). A mix-
ture of selenadiazolo[3,4-f]quinolone 9 (2.0 g, 8.0 mmol) and
POCl3 (4 mL, 6.56 g, 42.8 mmol) was stirred at 90 °C for 3 h.
After the reaction was complete, the mixture was cooled to 0 °C
in an ice bath followed by the addition of crushed ice (~30 g) in
one portion under stirring. Once the ice was melted, the
resulting brown solution was stirred for 45 min and subse-
quently alkalised with a 20% NaOH solution under cooling in
the ice bath. The grey–brown precipitate was collected by
suction, washed with water and dried. Purification by FLC
(silica gel, CHCl3, Rf = 0.21) afforded 9-chloroselenadiazolo-
quinoline 10 (1.90 g, 89%) as a pale yellow solid; mp
225–226 °C. 1H NMR (300 MHz, TFA-d) δ 8.02 (d, 1H, J = 9.7
Hz, H-4), 8.06 (d, 1H, J = 6.3 Hz, H-8), 8.26 (d, 1H, J = 9.7 Hz,
H-5), 8.69 (d, 1H, J = 6.1 Hz, H-7); 13C NMR (75 MHz, TFA-
d) δ 125.2, 126.1, 129.9, 134.5, 143.3, 145.8, 155.2, 158.6,
159.7; anal. calcd for C9H4ClN3Se: C, 40.25; H, 1.50; N, 15.65;
found: C, 40.21; H, 1.51; N, 15.67.
1H and 13C NMR spectra of compounds 2–6, 8, 10 and 11.
Acknowledgements
The authors wish to express their gratitude to the Scientific
Grant Agency (VEGA project 1/0660/11) and to the Slovak
Research and Development Agency (contracts nos. APVV-
0339-10 and APVV-0038-11) for the financial support received.
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