GB597835A - Improvements in the preparation of etherified rydroxy nitroanilines - Google Patents

Abstract

2-RO-5-nitroanilines, occasionally with 2-RO-4-nitroanilines, wherein O is an oxygen atom and R is an alkyl, alkenyl, aralkyl or aralkenyl group containing at least three carbon atoms, are prepared by mono-nitrating a 2-RO-aniline (which may contain methyl groups in the 3-, 4- or 6-positions), or an N-acylated derivative thereof, with, for example, nitric acid either alone, with strong sulphuric and/or glacial acetic acid or in ethereal solution with acetic anhydride, and if necessary hydrolysing the acrylamino group. The mixture of acylated 2-RO-nitroanilines may be separated by hydrolysing the 2-RO-4-nitroacylaniline in a solution of absolute alcohol in the presence of an alcoholate as catalyst and dissolving it in a dilute mineral acid, the 2-RO-5-nitroacylaniline being recovered from the precipitate by saponification. The acyl group may be an acetyl, benzoyl, carbethoxyl, or toluene sulphonyl group. In examples: (1) 2-n-propyloxyacetanilide is treated with nitric acid to produce the 4- and 5-nitroacetanilides, from which the corresponding nitranilines are separated by selective saponification as above, using sodium propylate in propanol; (2) as in (1) with benzyloxyinstead of n-propyloxy; (3) the crude product of (1) is hydrolysed with dilute hydrochloric acid, when 2-n-propyloxy-4-nitroaniline separates from the solution on exact neutralization and 2-n-propyloxy-5-nitroaniline is obtained by making the filtrate alkaline; (4) and (5) 2-n-propyloxy-acetanilide is treated with nitric acid in strong sulphuric acid and glacial acetic acid and 2-n-propyloxy-5-nitroaniline is obtained by (4) recrystallization from propanol and hydrolysis, and (5) hydrolyses with dilute hydrochloric acid and recrystallization of the hydrochloride; (6) 2-n-propyloxy aniline was nitrated as in (4) and the 2-n-propyloxy-5-nitroaniline purified by recrystallization from propanol and petroleum ether; (7) as in (6) with n-butyloxyinstead of n-propyloxy-; (8) the product of (6) was acetylated and pure 2-n-propyloxy-5-nitroacetanilide was obtained by recrystallization from propanol. Specification 594,816 is referred to. Samples have been furnished under Sect. 2 (5) of products prepared by nitrating 2-allyloxy-acetanilide and working up as in example (3) above to produce (A) 2-allyloxy-4-nitroaniline and (B) 2-allyloxy-5-nitroaniline. The Specification as open to inspection under Sect. 91 comprises also the cases where R is unlimited as regards the number of carbon atoms therein and may also be aryl, and refers to substituents other than methyl in the 3-, 4-and 6-positions. This subject-matter does not appear in the Specification as accepted.