Process of selectively blocking amino functions in aminoglycosides using transition metal salts and intermediates used thereby

The process for selectively blocking amino groups with an acyl blocking group, Y, in a polyamino-organic compound, at least one of said amino groups having an available neighboring hydroxyl group, and at least one of said amino groups being either devoid of, or sterically less available to, an available neighboring hydroxyl group;

• which comprises the reaction of said polyamino-organic compound in an inert organic solvent, with a salt of a divalent transition metal cation selected from the group consisting of copper (II), nickel (II), cobalt (II) and cadmium (II) or with mixtures thereof, whereby is formed a complex of said polyamino-organic compound between said transition metal salt and said available neighboring amino and hydroxyl group pairs;
• followed by the reaction in situ of the resulting polyamino-organic compound-transition metal salt complex with an amine blocking reagent having an acyl blocking group Y;
• thence reaction of the resulting polyamino-organic compound-transition metal salt complex having acyl blocking groups, Y, on non-complexed amino groups, with a transition metal precipitating reagent or with ammonium hydroxide, whereby said transition metal cation is removed.