Hoechst Aktiengesellschaft

Manfred Hintzmann

Hartmut Heise

Theodor Papenfuhs

Dieter Heck

A process for the preparation of 4-acylamino-2-aminoalkoxybenzenes of the general formula (1) ##STR1## in which R denotes an alkyl-C.sub.1 -C.sub.6 - or alkoxy-C.sub.1 -C.sub.4 -alkylene-C.sub.1 -C.sub.4 group and R' denotes a methyl or ethyl group, by pumping a solution or suspension of a 2,4-dinitroalkoxybenzene of the general formula (2) ##STR2## in which R has the abovementioned meaning, in a butyl acetate into a stirred suspension of a nickel catalyst on a kieselguhr carrier in butyl acetate, which has been initially introduced into an autoclave, at a hydrogen pressure of about 5 to about 50 bar, and a temperature of about 60.degree. to about 120.degree. C., at a rate which corresponds to the rate of hydrogenation of 2,4-dinitroalkoxybenzene to 2,4-diaminoalkoxybenzene, dehydrating the reduction solution by azeotropic distillation, after the hydrogenation, and acylating the resulting 2,4-diaminoalkoxybenzene with about 0.90 to 0.99 mole of the anhydride of an alkylmonocarboxylic acid having 2 to 3 carbon atoms, relative to 1 mole of 2,4-diaminoalkoxybenzene, at about -5.degree. to about +15.degree. C.

Process for the preparation of 4-acylamino-2-aminoalkoxybenzenes

A process for the preparation of o-nitrophenetole by allowing about 1.05 to about 1.4 mole of ethanol to act on 1 mole of o-nitrochlorobenzene in the presence of a phase-transfer catalyst in approximately 40 to approximately 70 percent by weight alkali metal hydroxide solution at temperatures from about 50.degree. to about 80.degree. C. in such a way that the ethanol concentration in the reaction mixture does not exceed 1.5 percent by weight throughout the course of the reaction.

Process for the preparation of o-nitrophenetole

A process for the preparation of 2,4-dinitrophenyl ethers of the general formula (1) ##STR1## in which R denotes an alkyl(C.sub.1 -C.sub.6) or alkoxy(C.sub.1 -C.sub.4)alky(C.sub.1 -C.sub.4) group by reacting 1 mole of 2,4-dinitrochlorobenzene in the anhydrous alcohol which is required for the ether formation and is of the general formula (2)

Process for the preparation of 2,4-dinitrophenyl ethers

Process for the preparation of pure 3-acetylaminoanilines of the general formula (1) ##STR1## in which R denotes a hydrogen atom or an alkoxy group with 1-4 carbon atoms, by reduction of 1,3-dinitrobenzene in an alkanol with 1-4 carbon atoms to the 1,3-diaminobenzene or by reaction of 2,4-dinitrochlorobenzene with sodium hydroxide in an alkanol with 1-4 carbon atoms and subsequent reduction to the 2,4-diaminoalkoxybenzene, and in each case subsequent monoacetylation in the alkanol mentioned to give the 1-amino-3-acetylamino-benzene or the 2-amino-4-acetylamino-alkoxy-benzene and isolation of the compound of the above formula (1) obtained in the alkanolic solution, which optionally contains water, which comprises carrying out the isolation by precipitation of the compound of the above formula (1), in the form of the hydrohalide, from the alkanolic solution by means of hydrogen halide or aqueous hydrogen halide acid and subsequent filtration.

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Hofheim am Taunus, Germany

Manfred Hintzmann