To a stirring solution of (492 g, 1.68 mmoles) benzoylmercaptoacetyl-N-hydroxysuccinimide and (150 mg, 0.84 mmoles) 1,3-diaminoacetone hydrochloride monohydrate in (15 mL) dioxane was added (850 mg, 8.40 mmoles) triethylamine. The reaction stirred 3.5 days followed by rotavapping off the dioxane to a yellow oil and adding (3 mL) water to a yellow solid. The solid was crushed, filtered, washed with water, and dried in vacuo yielding 242 mg, 65% N,N'-bis-(S-benzoylmercaptoacetyl)-1,3-diaminoacetone (m.p. 134°-140° C.).
