Réaction #48896

Équation de réaction

ether

1-ethyl-3-methyl-2-((1E,3E)-4-phenylamino-buta-1,3-dienyl)-5-sulfo-3-(3-sulfo-propyl)-3H-indolium sodium 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}-1-ethyl-3-methyl-5-sulfo-3-(3-sulfo-propyl)-3H-indolium trisodium 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-5b) was extracted by suction
4. 4
   Lavagewashed with ether
5. 5
   Autredried

Mode opératoire

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.

Source