1-Chloro-2,4-Dinitrobenzene → 2,4-Dinitrophenetole

Participants

Reaction Steps

Into a 2-liter resin kettle, equipped with stirrer, reflux condenser and thermometer, was charged 632 g. ethanol. To the ethanol was added carefully, below 50° C., in 15-20 minutes, 42.0 g. sodium hydroxide. To this was added, in 15 to 20 minutes, 213 g. 2,4-dinitrochlorobenzene, with the temperature maintained below 50° C. The resulting mixture was heated to reflux and held at reflux for 3 hours to give an ethanol solution of 2,4-dinitrophenetole. After cooling to room temperature, the ethanolic reaction solution was treated with 340 g. iron powder and 200 ml. water, exhibiting a mild exotherm. A solution of 12 ml. hydrochloric acid, 12 ml. glacial acetic acid and 100 ml. water was added dropwise over 1 hour at a rate to maintain 62°-75° C. This reaction mass was refluxed under a nitrogen atmosphere for 3 hours, then cooled to 0° to 5° C., and assayed for 2,4-diaminophenetole by perchlorate titration. To the cooled reaction mass was added 80 g. sodium hydroxide (50% aqueous solution), and then an exact equivalent amount of acetic anhydride, about 90-94 g. acetic anhydride, depending on the perchlorate assay. The temperature was maintained at 0° to 5° C. during this addition. The acetic anhydride was added dropwise over a period of about 2.5 hours. Following the addition of the acetic anhydride, the pH was adjusted to 6.8-7.0. The reaction product was treated with 20 g. of activated charcoal and 10 g. of diatomaceous earth at 80° C. and filtered to clarify. The filter residue was washed three times with 50 ml. of hot 1:1 ethanol-water. The combined filtrate and washings was heated to distill off ethanol, until the pot temperature reached 98° C. The aqueous pot residue was cooled to 10°-15° C. and filtered to give substantially pure crystalline product, assayed at 126 g. of 3-amino-4-ethoxyacetanilide, 65-70% of theory, based on the 2,4-dinitrochlorobenzene starting material.

Provenance & Evidence