DE319970C - Process for the preparation of p-nitrophenylurea derivatives - Google Patents

Description

. Process for the preparation of p-nitrophenylurea derivatives. By - Implementation of phosgene and p-nitroaniline according to patent 318237 (addition to patent 241822) easily accessible p-nitrophenylurea chloride with amines According to the present process, new or previously difficult to access ureas to win.

The great reactivity of the long-known p-nitrophenylurea chloride (American chemical journal 19, p. 318) opposite amines was surprising as it has never been used for such reactions and has a reaction-inhibiting effect of the p-position nitro group was to be feared, as for example Eug. Bamberg in reports 3o, page 1249, for the o-p-nitrodiazobenzenic acid ester would have. In fact, such a reaction-inhibiting effect of the p-position Nitro group in the p-nitrophenyl urine chloride without further detection. For example Aniline 'in a solution of excess phosgene in inert agents, e.g. B. Benzene or nitrobenzene, brought at ordinary temperature, forms over the initially resulting mixture of phenylurea chloride and hydrochloric acid Aniline removes hydrochloric acid after a long period of time the diphenylurea. The phenylurea chloride initially formed therefore has hydrochloric acid compared to it. Base has a much greater reactivity than the excess phosgene. In the Carry out the same experiment using suspended in nitrobenzene However, p-nitroaniline only forms p-nitrophenylurea chloride. So is the p-nitrophenylurea chloride in indifferent agents to the hydrochloric acid Base less reactive than Pliosgen and consequently less reactive than phenylurea chloride.

Different - on the other hand the conditions are, if an attempt is made, the two -Urea chlorides in aqueous suspension with z. B. amines dissolved in water in Bring reaction. During this process, phenylurea chloride rapidly breaks down into phenyl isocyanate and proves to be very inert in this form, so that unsymmetrical ureas cannot be made this way. In contrast, it sits down the much more stable p-nitrophenylurea chloride in aqueous suspension smoothly to unsymmetrical ureas. The reaction of the p-nitrophenylurea chlorides with amines is therefore unpredictable in indifferent agents as well as in water, - since a smooth implementation could not be expected a priori.

Examples. 1. 19.5 parts of p-nitrophenylurea chloride and 13.8 parts p-Nitraniline are heated in 300 parts of nitrobenzene with stirring until all hydrochloric acid has escaped. The yellow conversion product obtained is after Sucked off to cool, washed with fuel and dried. It's identical to that well-known p-p-dinitrodiphenylurea, which is a greenish yellow lacquer dye is. Instead of nitrobenzene, other inert solvents or suspending agents can also be used be applied.

In addition, the formation and further conversion of the p-nitrophenylurea chloride can be combined into one operation in the example. This is achieved by the action_-vpn z Mgl. I? Hosgen on 2. Mol. P-Nitranilin und_riachherige, high heating of the but can also arise directly zggjäef ::, 2 mol. p-nitroaniline come into effect in solvents that are not too hot: If in the above example, instead of p nitramline, other bases, e.g. B. aniline; Toluidines, naphthylamines, aminoanthraquinones, halonitroamines, etc., under suitable conditions, e.g. B. Application. excess bases or other hydrochloric acid binding agents, mixed p-nitrophenylureas are formed.

2. 23.1 parts of sodium sulfanil are mixed with 250 parts of water, 13.6 parts kryst. Sodium acetate or the equivalent amount of soda with the addition of 20.8 parts of p-nitrophenylurea chloride pebbles until a uniform yellow Porridge has arisen. The same is dissolved in hot water, filtered and after Sucked off to cool, washed with a little water and dried. The thus obtained p-pl @ nitrodiphenylurea sulfonic acid sodium salt is a yellow colored crystal powder which is much more difficult to dissolve in water than sodium sulphate. By suitable reduction, e.g. B. Sodium sulfur solution ulw., The corresponding forms more soluble, uncolored amino compound.

In this example, the sulfanilic acid salt can be represented by "the isomers, are replaced by equivalent homologous and substituted su'fosaure salts, the same by naphthylamine sulfonic acid, aminonaphto: sulfonic acid _ salts, etc., whereby products are obtained, which are generally less soluble than the salts of the used Sulfonic acids.

3. 2o, 8 parts of p-pl-diamino @ tilbenedisulfosaures sodium are with 13.6 kg of kryst. Sodium acetate or a corresponding other hydrochloric acid binding agent Means in 60o parts of water with the addition of 2o.8 parts of p-nitrophenylurea chloride Vigorously stirred or balled until the product appears uniform. The obtained, f-strong yellow colored ethylene - bis -_p-pl-nitrodiphenylureasidfosaure. Sodium is due to its more difficult solubility analogous to the information in the example s worked up. It already has a weakly substantive character. Through reduction and further exposure to p-nitrophenylurea chloride can turn it into valuable new ones Products are transferred.

Instead of the p-pl-diaminostilbene disulfonic acid salts, other, z. B. benzidinsulfosaure salts etc. can be used.

Claims (2)

PATENT CLAIMS: x. Process for the preparation of p-I`titrophenylurustoffderivaten, characterized in that p-nitrophenylurea chloride with primary or secondary bases or their substitution products, such as, in particular, sulfonic acids, Oxysulfonic acids, etc., with or without hydrochloric acid binding agents. 2. Special Execution of the method according to claim x, consisting in that one in the Rä3le the representation of the symmetrical p-p1-dinitrodiphenylurea on 2 mol. p-nitroaniline x Mol. Phosgene at not too high initial temperatures to the effect. _