Methanol → Xanthene

Participants

Reaction Steps

In a 500 ml four-neck flask, 41.0 parts of a sulfofluoran compound of the following chemical formula (5), 312 parts of methanol, 6.79 parts of N-methyl-2,6-xylidine and 6.13 parts of N-methyl-o-toluidine were put and refluxed for 30 hours. The reaction solution was filtered at 60° C. to remove insoluble substances therefrom. Then, the solvent was removed under a reduced pressure, until the amount of the reaction solution reached about 70 ml. The reaction solution was poured into 200 parts of 6% hydrochloric acid. Then, 600 parts of water was added thereto and the mixture was stirred at room temperature for 30 minutes. Then, a wet cake was obtained by filtration. The wet cake was suspended in 100 parts of water and stirred at 60° C. for 2 hours. Then, the wet cake was obtained again by filtration, washed with hot water at 60° C. and then dried, thereby obtaining the xanthene-based dye A represented by the following chemical formula (6).

Provenance & Evidence