Reaction equation
[NH2:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[CH:8]=[C:7]([S:12]([OH:15])(=[O:14])=[O:13])[CH:6]=[CH:5]2.[Na].[OH-].[Na+].Cl[C:20]([O:22][CH2:23][C:24]1[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=1)=[O:21]>O>[C:20]([NH:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[CH:8]=[C:7]([S:12]([OH:15])(=[O:13])=[O:14])[CH:6]=[CH:5]2)([O:22][CH2:23][C:24]1[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=1)=[O:21]Participants
Procedure
To a suspension of 6-aminonaphthalene-2-sulfonic acid, sodium salt (3 g, 12.2 mmol) in 70 mL of water is added solid NaOH (1.01 g, 25 mmol) at room temperature. The mixture is stirred for 1 hour, and benzyl chloroformate (3.43 mL, 24 mmol) is then added. The resulting mixture is stirred over a period of 16 hours. The crude product is treated as in EXAMPLE 24, Part A to give 4.70 g of crude N-CBz-6-aminonaphthalene-2-sulfonic acid, sodium salt. A mixture of the sulfonic acid, sodium salt (2.3 g, 6.10 mmol) in 15 mL of thionyl chloride is heated at 80° C. for 5 hours. The mixture is allowed to cool to room temperature and concentrated in vacuo. The residue is diluted with EtOAc and washed successively with water (2×), saturated NaHCO3 solution and saturated NaCl. The organic layer is dried over anhydrous MgSO4, filtered and concentrated to give a solid. The crude product is triturated from 50% EtOAc/hexanes to afford the title compound (0.50 g, 1.33 mmol) as a beige solid.
Workup
- stirringThe resulting mixture is stirred over a period of 16 hours
Sources & evidence
- ORD record
- ord-b50a8aa83eaa45b4875264bf95275b9a
- Source dataset
- uspto-grants-1999_09
- Patent number
- US05958918
Linked notes
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