Phenothiazine → Sodium 3-(10H-phenothiazin-10-yl)propane-1-sulfonate

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Reaction Steps

A portion of sodium hydride (17.7 g, 0.44 moles) dispersed in mineral oil is first washed with petroleum ether (b.p. 40-60° C.) and then suspended in 200 mL dry tetrahydrofuran, in a 2 L three-neck flask. A solution of phenothiazine (80.0 g, 0.4 moles) dissolved in tetrahydrofuran (400 mL) is added under argon through a cannula. The mixture is shaken, always under argon, for one hour at room temperature and then for 30 minutes at 50° C. The mixture acquires an orange colour, following the formation of the phenothiazine anion. After the suspension has cooled to 0° C., a solution of 1,3-propanesultone (35 mL, 0.4 moles) in tetrahydrofuran is added also through a cannula. The colour of the mixture changes almost immediately to clear yellow. The mixture is stirred at 0° C. for thirty minutes after the addition of the sultone and then at room temperature for another thirty minutes.

Provenance & Evidence