Back to results
US 5,605,976 AGranted
Method of preparing polyalkylene oxide carboxylic acids
AssigneeEnzon, Inc.
InventorsAnthony J. Martinez, Richard B. Greenwald
Life of this patent
Estimating the term…
Abstract
The present invention is directed to methods of preparing high purity polyalkylene oxide carboxylic acids. The methods include reacting a polyalkylene oxide such as polyethylene glycol with a t-butyl haloacetate in the presence of a base followed by treatment with an acid such as trifluoroacetic acid. The resultant polymer carboxylic acids are of sufficient purity so that expensive and time consuming purification steps required for pharmaceutical grade polymers are avoided.
Claims23
A method of preparing a polyalkylene oxide containing a terminal carboxylic acid, comprising:
- i) reacting a polyalkylene oxide with a tertiary alkyl haloacetate in the presence of a base to form a tertiary alkyl ester of polyalkylene oxide carboxylic acid;
- and
- ii) reacting said tertiary alkyl ester with an acid to form said polyalkylene oxide carboxylic acid.
Dependencies are inferred from the claim text.