How is N,N'-Bis(1,3-dihydroxy-2-propanyl)-2,4,6-triiodo-5-(lactoylamino)isophthalamide (CAS: 60166-93-0) typically synthesized?

N,N'-Bis(1,3-dihydroxy-2-propanyl)-2,4,6-triiodo-5-(lactoylamino)isophthalamide is synthesized through a multi-step process involving the iodination of 2,4,6-triiodo-5-carboxylic acid and subsequent amidation with 1,3-dihydroxy-2-propanol and lactoyl chloride. The reaction typically requires the use of a Lewis acid catalyst, such as aluminum chloride, to facilitate the amidation step. The final product is isolated through recrystallization from an appropriate solvent, ensuring a high yield of the desired compound.