Abstract: A process for purification of water soluble polymers is provided. A polymer of interest can be separated from a mixture of polymers, provided the polymer of interest differs from other polymers in the mixture in the number of reactive terminal groups. The process involves derivatizing polymers at the reactive terminal groups with a derivatizing molecule, bearing either (i) two or three cationic or anionic ionizable groups, and a group capable of covalent bonding to the reactive terminal groups or (ii) three or four ionizable groups, at least one of which is capable of covalent bonding to the reactive terminal groups; followed by ion exchange. The process allows removal of PEG from MPEG, and can be used for polymers having an average size greater than 9,000 Da Derivatization may be reversible in order to allow re-use of recovered contaminant polymers.

Abstract: A process for purification of water soluble polymers is provided. A polymer of interest can be separated from a mixture of polymers, provided the polymer of interest differs from other polymers in the mixture in the number of reactive terminal groups. The process involves derivatizing polymers at the reactive terminal groups with a derivatizing molecule, bearing either (i) two or three cationic or anionic ionizable groups, and a group capable of covalent bonding to the reactive terminal groups or (ii) three or four ionizable groups, at least one of which is capable of covalent bonding to the reactive terminal groups; followed by ion exchange. The process allows removal of PEG from MPEG, and can be used for polymers having an average size greater than 9,000 Da Derivatization may be reversible in order to allow re-use of recovered contaminant polymers.

Abstract: 4-Oxo-4,5-dihydro-3H-pyrrolo[3,2-d] pyrimidine-7-carboxylic acid methyl ester and process for preparing are provided. The process for producing the 4-oxo-4,5-dihydro-3H-pyrrole[3,2-d]pyrimidine-7-carboxylic acid methyl ester comprises condensing 3-amino-1H-pyrrole-2,4-dicarboxylic acid dimethyl ester with formamidine acetate. The 4-oxo-4,5-dihydro-3H-pyrrole[3,2-d]pyrimidine- 7-carboxylic acid methyl ester is useful as a precusor for providing 9-deaza-hypoxanthine, a key intermediate for producing certain PNP inhibitors.

Abstract: 4-Oxo-4,5-dihydro-3H-pyrrolo[3,2-d] pyrimidine-7-carboxylic acid methyl ester and process for preparing are provided. The 4-oxo-4,5-dihydro-3H-pyrrole[3,2-d] pyrimidine-7-carboxylic acid methyl ester is useful as a precursor for providing 9-deaza-hypoxanthine, a key intermediate for producing certain PNP inhibitors.