1-Bromo-3-chloropropane → 1-(3-chloropropyl)-5,6-dihydro(1H,4H)-1,2,5-thiadiazolo[4,3,2-ij]quinoline 2,2-dioxide

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Reaction Steps

1-(3-Chloropropyl)-5,6-dihydro(1H,4H)-1,2,5-thiadiazolo[4,3,2-ij]quinoline 2,2-dioxide can be obtained as follows: a solution of 5,6-dihydro-(1H,4H)-1,2,5-thiadiazolo[4,3,2-ij]quinoline 2,2-dioxide (4 g) in dry N,N-dimethylformamide (30 cc) is added dropwise to a suspension of sodium hydride (0.69 g, 80% suspension in oil) in N,N-dimethylformamide (20 cc). After 30 minutes' stirring, a solution of 1-bromo-3-chloropropane (3.25 g) in N,N-dimethylformamdide (20 cc) is added. The reaction mixture is stirred at 25° C. for 2 hours and is then diluted in a mixture of water (300 cc) and ethyl acetate (300 cc). The organic phase is washed with water (3×200 cc), is dried over magnesium sulphate and is concentrated to dryness under reduced pressure (2.7 kPa). The residue is chromatographed on a column of silica gel (0.2-0.063-mm particle size, 4-cm diameter, 50-cm height), and eluted at a pressure of 0.7 bars of nitrogen with a mixture of cyclohexane and ethyl acetate (80-20 by volume), 125-cc fractions being collected. Fractions 4 to 12 are combined and concentrated to dryness under reduced pressure (2.7 kPa) to give 1-(3-chloropropyl)-5,6-dihydro-(1H,4H)-1,2,5-thiadiazolo[4,3,2-ij]quinoline 2,2-dioxide (4.2 g) in the form of a yellow oil.

Provenance & Evidence