Diatrizoate → 3,5-Diacetylamino-2,4,6-triiodobenzoic acid-2,3-dihydroxypropyl ester
Reaction equation
[Na].[C:2]([NH:5][C:6]1[C:7]([I:21])=[C:8]([C:12]([I:20])=[C:13]([NH:16][C:17](=[O:19])[CH3:18])[C:14]=1[I:15])[C:9]([OH:11])=[O:10])(=[O:4])[CH3:3].Cl[CH2:23][CH:24]([OH:27])[CH2:25][OH:26]>>[OH:27][CH:24]([CH2:25][OH:26])[CH2:23][O:10][C:9](=[O:11])[C:8]1[C:7]([I:21])=[C:6]([NH:5][C:2](=[O:4])[CH3:3])[C:14]([I:15])=[C:13]([NH:16][C:17](=[O:19])[CH3:18])[C:12]=1[I:20]Participants
Procedure
20 g (29 mmol) 3,5-diacetylamino-2,4,6-triiodobenzoic acid-2,3-dihydroxypropyl ester, which can be obtained from the sodium salt of 3,5-diacetylamino-2,4,6-triiodobenzoic acid by reaction with 3-chloropropane-1,2-diol at 105° C. (analogous to Organikum, 12th Edition, Deutscher Verlag der Wissenschaften, Berlin 1973, p.227 et seq.), are dissolved in 80 ml absolute pyridine and cooled to -10° C. To this solution is added dropwise 20 g (130 mmol) of commercially available methacrylic acid anhydride (Fluka) and the mixture is then stirred overnight at room temperature. The resulting clear reaction mixture is mixed with 1 l dilute hydrochloric acid and the white precipitate which forms is filtered off, washed with water to neutral and then reprecipitated from methanol/water. After drying in a fine vacuum (approx. 1 mbar, at room temperature) to a constant weight, 16.1 g (67.1%) colourless powder of amorphous appearance with a DSC melting point of 207° C. is obtained. 1 g of the substance is compressed as described in Example 1 into a tablet and irradiated; there is no discoloration.
Sources & evidence
- ORD record
- ord-2ae27a9fb0e74d0c96e22d61eec85e9a
- Source dataset
- uspto-grants-1998_07
- Patent number
- US05780668
Reaction notes
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