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ChemicalBook CAS DataBase List EOSIN B
56360-46-4

EOSIN B synthesis

4synthesis methods
-

Yield: 90%

Reaction Conditions:

with sulfuric acid;nitric acid at 0 - 20; for 12 h;

Steps:

Synthesis of the free dyes eosin Y (2) and eosin B (4)
Eosin B (EoB, 4): DBF (3, CycloLab, 300 mg, 0.612 mmol) was dissolved inconcentrated sulfuric acid (15 mL) and cooled to 0 °C. A mixture of 0.210 mL of nitricacid and 0.600 mL of sulfuric acid was added dropwise to the reaction mixture undervigorous stirring and cooling. The progress of the reaction was monitored by TLC(EtAc/methanol/NH3 (25%) 8:2:1). After 12 h of stirring at rt, TLC monitoring showedcomplete conversion of starting material and the reaction mixture was poured ontocrushed ice. The formed yellow precipitate was filtered, washed with water (3 × 10mL) and dried to constant weight at 105 °C under reduced pressure (10 mbar) in thepresence of P2O5 and KOH. The final product, EoB 4 was obtained after drying ayellow solid material in 90% (320 mg) yield.

References:

Benkovics, Gábor;Afonso, Damien;Darcsi, András;Béni, Szabolcs;Conoci, Sabrina;Fenyvesi, éva;Szente, Lajos;Malanga, Milo;Sortino, Salvatore [Beilstein Journal of Organic Chemistry,2017,vol. 13,p. 543 - 551] Location in patent:supporting information

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