PROCESS FOR THE PREPARATION OF 2-ALKOXY-5-N (SUBSTITUTED OR UNSUBSTITUTED) SULPHAMIDO-BENZOIC ACIDS

摘要

1,204,406. Sulphamide benzoic acid derivatives. SOC. D'ETUDES SCIENTIFIQUES ET INDUSTRIELLES DE L'ILE - DE - FRANCE. 22 March, 1968 [23 March, 1967; 31 March, 1967; 6 April, 1967], No. 14067/68. Heading C2C. The invention comprises compounds of the Formula I: in which A is an alkyl C 1 _ 5 or alkenyl radical C 1-5 and B is an amino or mono- or dialkylamino radical of low molecular weight C 1-5 in which the alkyl groups may be joined together by a -CH 2 - group or a N, O or S atom, to form a heterocycle having up to 5 carbon atoms, and the N atom may be linked to an alkyl group of low molecular weight C 1-5 , which may be prepared by treating a 2-alkoxy-5-chlorosulphonylnitrobenzene with ammonia or an amine, reducing the 2-alkoxy-5-N-(substituted or unsubstituted)-sulphamido-nitrobenzene formed, diazotizing the amino derivative formed and converting the diazo compound into a nitrile by the Sandmeyer method to obtain the nitrile I. This may subsequently be hydrolysed, if desired, to the acid. The preparations of 2- methoxy-5-sulphamido-benzonitrile, 2-ethoxy- 5 - dimethylsulphamido - benzonitrile and the corresponding benzoic acids are described. Heterocyclic ring systems defined by B include pyrrolidine, piperidine, imidazolidine, piperazine, morpholine or thiazolidine. p-Chlorosulphonyl-ethoxybenzene is prepared by treating ethoxybenzene with sulphuric chlorohydrin. 2 - Ethoxy - 5 - chlorosulphonyl-nitrobenzene is prepared by nitrating p-chlorosulphonyl-ethoxybenzene. 2 - Methoxy - 5 - chlorosulphonyl - nitrobenzene is prepared by treating the sodium or ammonium salt of 3-nitro-4-methoxy-benzene sulphonic acid with phosphorus pentachloride. Ammonium 3 - nitro - 4 - methoxybenzene sulphonite is prepared by reacting ammonia with 2 - methoxy - 5 - chlorosulphonyl - nitrobenzene which is prepared by reacting sulphuric chlorohydrin with 2-nitro anisole which is prepared by reacting o-nitrophenol with dimethyl sulphate. Sodium 3 - nitro - 4 - methoxybenzene sulphonate is prepared by reacting phenol with sulphuric acid and sodium nitrate.