2.2 g of cystamine dihydrochloride were dissolved in 20 ml of water and adjusted to pH 10 with NaOH. 2.1 g of p-azidobenzenesulfonyl chloride were suspended in this solution and the suspension was stirred at room temperature for 5 hours. The precipitated N-(p-azidobenzenesulfonyl)cystamine was reacted with 2 g of succinic anhydride and stirred overnight. The resulting solution was acidified with HCl, subsequently filtered and washed with water. The residue was dried at room temperature in a high vacuum and gave 1.53 g of N-(p-azidobenzenesulfonyl) N'-(3-carboxypropionyl) cystamine. The IR showed bands at 3283 (amide NH) 2134 (azide), 1714 (acid carbonyl), 1650 (amide), 1589+1547 (aromatic), 1284 (COOH), 1328+1180 (arylsulfonyl ), 839 (p-disubst.benzene). TLC (silica gel--NH3 conc./EtOH=1%) Rf=0.7. m.p.: dec. at 163°.
