Trifluoroacetic acid → 2-(7-Amino-thianthren-1-yl)-6-morpholin-4-yl-pyran-4-one

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Reaction Steps

To a solution of [6-(6-morpholin-4-yl-4-oxo-4H-pyran-2-yl)-thianthren-2-yl]-carbamic acid tert-butyl ester (11.95 g, 23.4 mmol) in dichloromethane (150 ml) was added trifluoroacetic acid (30 ml) and left under stirring at room temperature overnight. The solvent was dried in vacuo revealing a viscous dark brown liquid. Saturated sodium bicarbonate solution (400 ml) was added to the residue, which was left to stir for 20 minutes. The brown precipitate was filtered, washing with water and left to dry in a vacuum desiccator overnight. The solid was then purified by column chromatography (silica, MeOH/Dichloromethane, 3:97, Rf=0.28). 1HNMR (300 MHz, CDCl3): δH=3.24 (2H, bs); 3.46 (4H, bs); 3.81 (4H, bs); 6.33 (1H, s); 6.58 (1H, m); 6.86 (1H, d); 7.21 (1H, d); 7.30 (1H, t); 7.38 (1H, d); 7.63 (1H, d); m/z (LC-MS, ESP), RT=3.8 min, (M++1)=411

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