Nitric Acid → 4-(Acetylamino)-2-ethoxy-5-nitrobenzoic Acid Methyl Ester

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A mixture of 118.6 parts of methyl 4-(acetylamino)-2-ethoxybenzoate, 200 parts of acetic acid and 156 parts of acetic acid anhydride was stirred and heated to 50° C. After cooling to 15° C. (ice-bath) there were added dropwise 47.1 parts of fuming nitric acid 100% using a bromine funnel: an exothermic reaction occured. The temperature was kept at about 20° C. by cooling in an ice-bath. Upon completion, the temperature was allowed to rise to 40° C. and stirring was continued at this temperature for one hour. If necessary the whole was cooled with ice-water to keep the temperature at about 40° C. When the exothermic reaction was ceased, the whole was allowed to cool for one hour and was further cooled to 0° C. The reaction mixture was poured onto ice-water while stirring. Upon stirring for one hour, the precipitated product was filtered off and dissolved in 1950 parts of dichloromethane. The solution was washed twice with 500 parts of water, dried, filtered and evaporated. The residue was crystallized overnight at room temperature from 2-propanol. The product was filtered off, washed with 2,2'-oxbispropane and dried, yielding 67.6 parts (47.9%) of methyl 4-(acetylamino)-2-ethoxy-5-nitrobenzoate; mp. 110° C. (intermediate 32).

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