Water → 4-(8-Benzyloxy-7-methoxy-2-oxo-2,3-dihydroimidazo[4,5-c]quinolin-1-yl)-3-fluorobenzonitrile

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Reaction Steps

4-(3-Amino-6-benzyloxy-7-methoxyquinolin-4-ylamino)-3-fluorobenzonitrile (2.99 g, 7.2 mmol) was dissolved in dichloromethane (69 ml) together with Hünig's base (iPr2EtN, 1.43 ml). The solution obtained was subsequently added dropwise with ice-bath cooling to a mixture of trichloromethyl chloroformate (diphosgene, 938 μl, 7.72 mmol) and dichloromethane (42 ml). When the addition was complete, the mixture was stirred at room temperature for a further 30 min. Saturated Na2CO3 (30 ml) and water (170 ml) were subsequently added. After stirring for a further 30 min, the mixture was extracted twice with ethyl acetate (225 ml each time). The combined organic phases were washed once with water (150 ml), dried over Na2SO4, filtered and evaporated to dryness in vacuo. The residue was chromatographed over flash silica gel (solvent gradient ethyl acetate/0-17% by vol. of ethanol), giving 4-(8-benzyloxy-7-methoxy-2-oxo-2,3-dihydroimidazo[4,5-c]quinolin-1-yl)-3-fluorobenzonitrile (1.87 g, 4.3 mmol) as solid. MS: 441.1 (M+H+), TLC (HPTLC): Rf=0.44 (ethyl acetate/ethanol 8:1, parts by volume).

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