4-Nitrophenyl chloroformate activation dextran

On the other hand, polymeric carriers can also be modified to introduce reactive groups. Polysaccharides such as dextran and inulin may be activated [149] by periodate oxidation to create aldehyde groups, by succinic anhydride activation to create carboxylic groups, or by p-nitrophenyl chloroformate activation to create reactive ester groups. 

Recently we have reinvestigated (16) the activation of dextran with 4-nitrophenyl chloroformate (VII). The content of the 4-nitrophenyl carbonate groups in activated dextran can be easily determined... 

This data demonstrate that during the activation of dextran with 4-nitrophenyl chloroformate different types of carbonate groups are formed and that, depending on the reaction conditions, the degree of activation might be much higher than what one would conclude from the data obtained from the "conventional" alkaline hydrolysis and U.V. assay of the 4-nitrophenyl groups. 

Figure 4. Total carbamate content ( ) and 4-nitrophenyl carbamate content (O) during the activation of dextran with 4-nitrophenyl chloroformate [anhydro glucosides]0 =0.1 M [chlorofor-mate]Q = 50 mM.

Carbamate content, activation of dextran with 4-nitrophenyl chloroformate, 193,194/... 

---