Hydrochloric Acid → 1,4-dithiophen-2-yl-2,5-dihydropyrrolo[3,4-c]pyrrole-3,6-dione

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

As a specific example embodiment, potassium tert-butoxide (67.4 g, 0.60 mol) and tert-amyl alcohol (400 mL) are added to a nitrogen-protected oven-dried three-neck round-bottom flask equipped with a mechanical stirrer, a thermometer and a reflux condenser. The mixture is heated to 105° C. for 1.5 h and to this mixture is added 2-thiophenenitrile (55.2 g, 0.50 mol) and the stirring continued at 105° C. for 30 min. A mixture of diisopropyl succinate (40.4 g, 0.20 mol) in tert-amyl alcohol (60 mL) is added dropwise over a period of 3 h with rapid stirring. The mixture is then stirred at 105° C. for a further 2 h, then cooled to 50° C., at which point a mixture of methanol (300 mL) and water (80 mL) is added. The reaction mixture is heated at reflux for 45 min before cooling to room temperature. The mixture is poured over 500 g of ice, then concentrated hydrochloric acid (35% aq) (150 mL) and methanol (750 mL) are added and the mixture is stirred for 45 min. The mixture is filtered and the solid is washed with methanol (200 mL). The solid is then suspended in water (1 L) and stirred for 30 min before being filtered again. This suspension in water, stirring and filtration is repeated a further three times. After filtering for the last time, the solid is oven dried at 80° C. for 16 h, then dried under vacuum to give the product, 3,6-bis(thiophen-2-yl)-2H,5H-pyrrolo[3,4-c]pyrrole-1,4-dione, (49.7 g, 82% yield) as a red solid. This compound is used without further purification. 1HNMR (d6-DMSO, 300 MHz): δ 7.27 (2H, t, J=3.0), 7.89 (2H, dd, J1=6.0, J2=3.0), 8.23 (2H, d, J=3.0), 11.00 (2H, s); 13CNMR (d6-DMSO, 75 MHz): δ 113.6 (2C), 127.1 (2C), 128.3 (2C), 130.5 (2C), 136.6 (2C), 142.6 (2C), 168.2 (2C); m/z (EI+) 300.0 [M]+; Anal. Calc. for C14H8N2O2S2: C, 55.98; H, 2.68; N, 9.33; S, 21.35.

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