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US 6,610,885 B1Granted
Process for the preparation of contrast agents
AssigneeAmersham Health AS
InventorsTrygve Gulbrandsen, Odd Einar Ingvoldstad, Lars Terje Holmaas
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Abstract
Process for the preparation of contrast agents The invention provides a process for the preparation of an N-alkyl-acylamino-phenyl-carboxylic acid or carboxylic acid derivative by liquid phase acylation and subsequent N-alkylation of a corresponding amino-phenyl-carboxylic acid (or carboxylic acid derivative), the improvement comprising the addition of an alkylating agent to a solution containing the reaction products of said acylation, to effect said N-alkylation.
Claims6
A process for the preparation of iohexol comprising the steps of:
- (a) forming a reaction mixture containing 5-acetamido N,N′-bis(2,3-dihydroxypropyl)-2,4,6-triodoisophthalamide, a base, a solvent and glycidol,
- (b) N-alkylating said 5-acetamido compound with the glycidol to form iohexol, and
- (c) isolating iohexol.
Dependencies are inferred from the claim text.