Nickel acetate tetrahydrate → Nickel Acetate

Add nickel (II) acetate tetrahydrate (24.8 gms. 10 mmol) to a stirred solution of kanamycin A (9.7 gms., 20 mmol) in dimethylsulfoxide (400 ml.). Stir at room temperature for 30 minutes, then to the resulting nickel (II) salt complex thereby formed add N-benzyloxycarbonyloxyphthalimide (13.0-15.6 gms., 44-52.6 mmol) in dimethylsulfoxide (70 ml.) over a 10 minute period. Stir at room temperature for one hour, then pour the reaction mixture into ether (2500 ml.) and shake one minute. Allow the oil to settle and decant the supernatant dimethylsulfoxide ether. Repeat this procedure two more times using 1500 ml. and 1000 ml., respectively, of ether. Dissolve the resultant gummy residue in methanol (1000 ml.) and concentrated ammonium hydroxide (50 ml.). Bubble hydrogen sulfide through the solution and separate the resultant precipitate of nickel (II) sulfide through a pad of Celite and wash the residue with methanol. Stir the combined filtrate and methanol wash with Amberlite IRA-401S (OH⃝) ion exchange resin (300 gms.), filter off the resin and evaporate the filtrate in vacuo. Triturate the resultant gummy residue with a 50:50 mixture of acetonitrile:ether and filter the resultant white solid to obtain 3,6'-di-N-benzyloxycarbonylkanamycin A; yield 12.5 gms. (83.5% theory); [α]D26 +78° (c, 4.84 in 50% aqueous methanol). Analysis Calculated for: C34H48O15N4.H2O; C, 56.2; H, 6.75; N, 6.94%. Found: C, 51.02; H, 6.26; N, 6.85%. E. Treat each of the following aminoglycosides with a mixture of cupric acetate hydrate and nickel (II) acetate tetrahydrate or with cobalt (II) acetate tetrahydrate or with cadmium (II) acetate dihydrate according to the procedures of Examples 11A through 11D, respectively.