1-Chloro-2,4-Dinitrobenzene → 6-Methoxy-3-acetylamino-aniline hydrochloride

Participants

Reaction Steps

197 parts of 37% strength hydrochloric acid are added dropwise, at 20°-25° C. in the course of 30 minutes, with stirring, to a dark solution, obtained according to Example 1 of European Pat. No. 0,011,048 by reaction of 213 parts of 2,4-dinitrochlorobenzene with 42 parts of sodium hydroxide in 632 parts of methanol, subsequent hydrogenation on Pd/charcoal at 60° C. and then acetylation with 98 parts of acetic anhydride in the presence of 22 parts of magnesium oxide at 0°-5° C., of 6-methoxy-3-acetylamino-aniline which, according to "high performance liquid chromatography analysis" ("HPLC analysis") contains 8.9 parts of 2,4-bis-acetylaminoanisole and 3.5 parts of 2,4-diaminoanisole, as well as black decomposition products formed by oxidation, in addition to 153 parts of the target product. The mixture is subsequently stirred for 1 hour and cooled to 0°-5° C. and the 6-methoxy-3-acetylamino-aniline hydrochloride precipitated is isolated by filtration. The product is washed twice with 100 parts of methanol to give, after drying in vacuo, 188.5 parts of 6-methoxy-3-acetylamino-aniline hydrochloride, which, besides about 5% of magnesium chloride, contains no organic by-products detectable by thin-layer chromatography ("TLC") or HPLC analysis. The product isolated thus corresponds to 179.1 parts of 100% pure 6-methoxy-3-acetylamino-aniline hydrochloride, which corresponds to a yield of 82.7% of theory, based on the 2,4-dinitrochlorobenzene employed.

Provenance & Evidence