Sodium hydride → 1-(4-chlorobutyl)-5,6-dihydro-(1H,4H)-1,2,5-thiadiazolo[4,3,2-ij]quinoline 2,2-dioxide

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Reaction Steps

1-(4-Chlorobutyl)-5,6-dihydro(1H,4H)-1,2,5-thiadiazolo[4,3,2-ij]quinoline can be prepared 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 (20 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-4-chlorobutane (3.93 g) in N,N-dimethylformamide (20 cc) is added. The reaction mixture is stirred at 20° C. for 2 hours and then diluted in a mixture of water (200 cc) and ethyl acetate (200 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 3 to 9 are combined and concentrated to dryness under reduced pressure (2.7 kPa) to give 1-(4-chlorobutyl)-5,6-dihydro-(1H,4H)-1,2,5-thiadiazolo[4,3,2-ij]quinoline 2,2-dioxide (4.5 g).

Provenance & Evidence