Process for the preparation of 4-hydroxalkylamino-2-nitro-anisoles
View Patent ↗A process for the preparation of 4-hydroxyalkylamino-2-nitro-anisoles of the general formula (I) wherein m is 2 or 3; by reaction of a 4-halogeno-3-nitro-aniline of formula (II) with a chloroalkyl-chloroformate of formula (III), alkaline ring closure of the resulting carbamate and nucleophilic replacement of the halogeno atom by a methoxy group to form a derivative of formula (IV), and finally ring opening of the resulting cyclic carbamate by treatment with methanolic alkali metal hydroxide, followed by neutralization with inorganic or organic acids, wherein the complete reaction is executed in a non-aqueous medium; as well as process for the preparation of 2-amino-4-hydroxyalkylamino-anisoles of formula (V)
1. A process for the preparation of 4-hydroxyalkylamino-2-nitro-anisoles of the general formula (I)
wherein m is 2 or 3;
wherein a 4-halogeno-3-nitro-aniline of formula (II) is caused to react with a chloroalkyl-chloroformate, followed by an alkaline ring closure of the resulting carbamate and a nucleophilic replacement of the halogeno atom by a methoxy group to form a derivative of formula (IV), and then followed by a ring opening of the resulting cyclic carbamate by a treatment with methanolic alkali metal hydroxide, and finally followed by a neutralization with an inorganic or organic acid, wherein the complete reaction is executed in a non-aqueous medium.
2. A process according to claim 1 , wherein said 4-halogeno-3-nitro-aniline of formula (II) is a 4-chloro-3-nitro-aniline or a 4-fluoro-3-nitro-aniline.
3. A process according to claim 1 , wherein said non-aqueous medium is an inert dipolar aprotic solvent.
4. A process according to claim 1 , wherein the first two reaction steps are performed at a temperature of from about 40° C. to about 60° C.
5. A process according to claim 1 , wherein said nucleophilic replacement of the halogeno atom is carried out with 3 equivalents of alkali methoxide per equivalent of said derivative of formula (IV).
6. A process according to claim 1 , wherein said alkali metal hydroxide is a sodium hydroxide or a potassium hydroxide.
7. A process for the preparation of 2-amino-4-hydroxyalkylamino-anisoles of the general formula (V)
wherein m is 2 or 3;
wherein the process according to claim 1 is followed by a reduction of said 4-hydroxyalkylamino-2-nitro-anisole of formula (I).
8. A process according to claim 7 , wherein a catalytic hydrogenation is used for the reduction of said 4-hydroxyalkylamino-2-nitro-anisole of (I).