Bioactive conjugates of cellulose with amino compounds

In a process for making conjugates of at least one amino compound containing at least one unsubstituted N-attached hydrogen atom, with at least one polymer which is selected from the group consisting of cellulose, polysaccharides other than cellulose and polyvinyl alcohol and its copolymers, and which contain a plurality of free hydroxy groups, which process comprises at least steps (a) and (b) of the following steps (a), (b) and (c), namely:

• (a) derivatizing the at least one polymer by reaction with at least one reactant for free hydroxy groups in said polymer, such reactant being selected from the group consisting of cyanogen halides, carbonate esters, halogenated s-triazines, haloformates, sulfonyl halides and N-heterocyclic compounds containing nuclear-bound active halogen atoms,
• (b) reacting the thus-derivatized polymer with at least one amino compound, and optionally
• (c) reconverting to hydroxy groups any polymer-bound groups which are the product of reacting polymer-bound hydroxy groups with such reactant;
• the improvement which comprises effecting a preactivation step prior to step (a) in order to increase the capacity of the at least one polymer for reaction with such at least one reactant, wherein said preactivation step consists of contacting said at least one polymer in absence of reactants for hydroxy groups, for a period of time sufficient to increase the capacity of the at least one polymer for reaction with such at least one reactant, with at least one N-heterocyclic compound selected from the group consisting of pyridine, pyrrole and pyridazine, partially hydrogenated analogs thereof, fully hydrogenated analogs thereof, and any of the foregoing which contain at least one substituent selected from C.sub.1-6 alkyl, C.sub.1-6 alkoxy, fluorine, chlorine, bromine and trifluoromethyl.