ChEBI: A dimeric, non-ionic, water-soluble, radiographic contrast agent, used particularly in coronary angiography.
Dimethyl 5-nitroisophthalate (215 g) and 1-amino-2,3-propandiol (196 g)were refluxed in methanol (500 ml). After twenty hours the solution was
cooled and stored in a refrigerator overnight. The product 5-nitro-N,N'-
bis(2,3-dihydroxypropyl)-isophthalamide was filtered and washed with
methanol. Yield: 270 g (84%). M.p. 128-132°C.
5-Nitro-N,N'-bis(2,3-dihydroxypropyl)-isophthalamide (18.1 g) was suspended
in water (250 ml), conc. hydrochloric acid (4.2 ml) and 10% PdO/charcoal
(0.5 g) were added, and the mixture hydrogenated in a Parr apparatus for one
day. After filtration the filtrate was heated at 80-90°C and 3.88 M NaICl2
(42.5 ml) was added through a dropping funnel over 1 hour. The solution was
heated for 2.5 hours. After cooling to 20°C 5-amino-2,4,6-triiodo-N,N'-
bis(2,3-dihydroxypropyl)-isophthalamide crystallized out.
5-Amino-2,4,6-triiodo-N,N'-bis(2,3-dihydroxypropyl)-isophthalamide (110 g)
was suspended in acetic anhydride (480 ml) and heated to 50°C.
Concentrated sulfuric acid (3 ml) was then added. The starting material was
dissolved after a few minutes, and the reaction mixture was heated at 60°C
for 75 min. After cooling the residue dissolved in methanol (300 ml) with
water (150 ml) the solution was heated to 50°C and the pH adjusted to about
10.5 by 10 N sodium hydroxide. After 4-5 hours the pH didn't decrease, and
the hydrolysis was complete. The reaction mixture was cooled to 20°C and
neutralized by adding hydrochloric acid. After stirring overnight 5-Acetamido-
2,4,6-triiodo-N,N'-bis(2,3-dihydroxypropyl)-isophthalamide was filtered and
washed with water. Yield: 94 g (80%). Melting point 275°C, dec.
2-Methoxyethanol (300 ml) and sodium hydroxide (20 g) was added to the
reactor at 50°C, and 5-acetamido-N,N'-bis(2,3-dihydroxypropyl)-2,4,6-
triiodoisophtalamide (304 g) was added after two hours of stirring. All solids
were allowed to dissolve overnight before cooling to 30°C and adjustment to
pH 12 with diluted hydrochloric acid. Epichlorohydrin (11 g) was added to the
solution after further cooling to 15°C, and the reaction was allowed to proceed
for 51 hours. As a result 1,3-bis(acetamido)-N,N'-bis[3,5-bis(2,3-
dihydroxypropylaminocarbonyl)-2,4,6-triiodophenyl]-2-hydroxypropane was
obtained.
Iodixanol is a viscous, isosmolar,nonionic, water-soluble dimer with 49% iodine content.It is formulated as an isotonic solution for intravascular injectionand indicated for excretory urography, angiography,and CT procedures.
