Pyridine → HCID 178462542, compound

Participants

Reaction Steps

500 mg (1 mmol) 1-ethyl-3-methyl-2-((E)-2-phenylamino-vinyl)-5-sulfo-3-(3-sulfo-propyl)-3H-indolium sodium salt 2 and 387 mg (1 mmol) 3-(3-carboxypropyl) -2,3-dimethyl-1-ethyl-3H-indolium iodide 3 salt were dissolved in a mixture of 10 ml acetic acid and 10 ml acetic anhydride. Subsequently, 5 ml pyridine was added. The solution was stirred under reflux for 15 minutes. After cooling to room temperature (about 20° C. to about 22° C.), 20 ml ether was added. The precipitate that was obtained, which was a mixture of the diastereomers 4.1 and 4.2, was extracted by suction, washed with ether, and dried. The residue was purified by column chromatography: RP-18: methanol/water 1/1.

Provenance & Evidence