Pyridine → HCID 178462546, compound

Participants

Reaction Steps

516 mg (1 mmol) 1-ethyl-3-methyl-2-((1E,3E)-4-phenylamino-buta-1,3-dienyl)-5-sulfo-3-(3-sulfo-propyl)-3H-indolium sodium salt and 483 mg (1 mmol) 3-(3-carboxypropyl)-2,3-dimethyl-5-sulfonato-1-(3-sulfopropyl)-3H-indolium sodium salt were dissolved in a mixture of 10 ml acetic acid and 10 ml acetic anhydride followed by the addition of 5 ml pyridine. The solution was stirred under reflux for 15 min. Twenty ml ether was added after cooling to room temperature. The obtained precipitate (mixture of the diastereomers OB-5a and OB-5b) was extracted by suction, washed with ether, and dried.

Provenance & Evidence