Calcium nitrate → Probicromil calcium
Reaction equation
[N+]([O-])([O-])=O.[Ca+2:5].[N+]([O-])([O-])=O.[O:10]=[C:11]1[CH:16]=[C:15]([C:17]([O-:19])=[O:18])[O:14][C:13]2[C:20]([CH2:32][CH2:33][CH3:34])=[C:21]3[C:26](=[CH:27][C:12]1=2)[C:25](=[O:28])[CH:24]=[C:23]([C:29]([O-:31])=[O:30])[O:22]3.[Na+].[Na+]>O>[O:28]=[C:25]1[CH:24]=[C:23]([C:29]([O-:31])=[O:30])[O:22][C:21]2[C:20]([CH2:32][CH2:33][CH3:34])=[C:13]3[C:12](=[CH:27][C:26]1=2)[C:11](=[O:10])[CH:16]=[C:15]([C:17]([O-:19])=[O:18])[O:14]3.[Ca+2:5]Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
A solution of calcium nitrate (2.0 g) in water (25 ml) was added to a solution of disodium 4,6-dioxo-10-propyl-4H,6H-benzo[1,2-b:5.4-b']dipyran-2,8-dicarboxylate (2.3 g) in water (25 ml) and the mixture was stirred for 30 minutes at room temperature. The precipitate was filtered off, washed well with water and ethanol and dried in vacuo at 70° C. to give the required calcium salt (1.7 g; 77%), m.p.>300° C.