反应详情

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.

1. customobtained
2. customat 0°-5° C.
3. customas well as black decomposition products formed by oxidation, in addition to 153 parts of the target product
4. stirringThe mixture is subsequently stirred for 1 hour
5. temperaturecooled to 0°-5° C.
6. customthe 6-methoxy-3-acetylamino-aniline hydrochloride precipitated
7. customis isolated by filtration
8. washThe product is washed twice with 100 parts of methanol
9. customto give
10. dry with materialafter drying in vacuo, 188.5 parts of 6-methoxy-3-acetylamino-aniline hydrochloride, which, besides about 5% of magnesium chloride