Pyridine → HCID 13710341, compound

Participants

Reaction Steps

Under a nitrogen atmosphere, a mixture of 5.0 g of 7-dimethylaminophenothiazin-3-one (commercially known as methylene violet), 75.0 ml of acetic anhydride, 5.0 ml of pyridine and 5.0 g of zinc dust was maintained at reflux temperature for approximately three hours. After cooling to room temperature, the reaction mixture was filtered to remove the insolubles and the filter cake was washed twice, each time with 50.0 ml of acetone. The combined filtrate and acetone washes was poured slowly into water and toluene was added to the resulting mixture. After stirring for approximately thirty minutes, the layers were separated and the water layer was discarded. The organic extract was treated with activated charcoal, filtered and the toluene was removed by evaporation at reduced pressure to obtain a gummy residue. The residue was dissolved with ethyl acetate and the resulting solution was passed through a chromatography column packed with silica gel using ethyl acetate to elute the column. The first four fractions were combined, concentrated, and the solid which formed was collected by filtration and dried to obtain 2.6 g of 7-dimethylamino-3-acetyloxy- 10-acetylphenothiazine (Formula I: R=R1 =R3 =CH), a white powder which melted at 124° to 128° C. The mass spectrum showed significant maxima at 342 (M+) and 299 (M+ -CH3CO). Paper coated with an ink formulation containing the product produced a blue-gray-colored image when contacted with an applied voltage stylus.

Provenance & Evidence