Réaction #48897

Équation de réaction

ether

3-methyl-2-((1E,3E)-4-phenylamino-buta-1,3-dienyl)-5-sulfo-1,3-bis-(3-sulfo-propyl)-3H-indolium disodium salt

3-(3-Carboxypropyl)-2,3-dimethyl-5-sulfonato-1-(3-sulfopropyl)-3H-indolium sodium salt

pyridine

→

2-{(1E,3E)-5-[3-(3-carboxy-propyl)-3-methyl-5-sulfo-1-(3-sulfo-propyl)-1,3-dihydro-indole-(2E)-ylidene]-penta-1,3-dienyl}-3-methyl-5-sulfo-1,3-bis-(3-sulfo-propyl)-3 H-indolium tetrasodium salt

Solvants

acetic acid

acetic anhydride

Conditions de réaction

Traitement

1. 1
   Températureunder reflux for 15 min
2. 2
   workup.ADDITIONThe obtained precipitate (mixture of the diastereomers
3. 3
   Extractionand OB-5.5b) was extracted by suction
4. 4
   Lavagewashed with ether
5. 5
   Autredried

Mode opératoire

642 mg (1 mmol) 3-methyl-2-((1E,3E)-4-phenylamino-buta-1,3-dienyl)-5-sulfo-1,3-bis-(3-sulfo-propyl)-3H-indolium disodium 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. Five ml pyridine was added. 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-5.5a and OB-5.5b) was extracted by suction, washed with ether, and dried.

Source