Hydrolysis of Di(aziridin-l-yl)sulphoxide to Ethyleneimine

Abstract

DI(AZIRIDIN-l-YL)SULPHOXIDE (DESO), which was synthesized as a potential anti-tumour agent, has been shown to possess the property of liberating ethyleneimine in the presence of phosphate ion¹. This communication reports a more detailed investigation of this effect. Ethyleneimine assay involved the colorimetric measurement (at 420 mµ) of the chloroform extract able dye obtained by reaction of the base with 1,2-naphthaquinone-4-sodium sulphonate in barbitone buffer (0.1 M, pH 9.6). The production of ethyleneimine from DESO was verified by comparing the absorption curves of the dyes derived from ethyleneimine and DESO (absorption maxima 303 and 425 mµ). On incubating DESO (2 mg/ml., 37° C) for 2 h in barbitone buffer over the pH. range 6.4–8.0 there was never more than 3 per cent hydrolysis, but at pH. 6.5 in phosphate buffer there was 74 per cent conversion to ethyleneimine. DESO was also quite stable on incubation in water, but addition of phosphate buffer resulted in the rapid production of ethyleneimine¹.