DE1292658B - Process for the production of ª ‰ -aminoaethyl aromatics - Google Patents

Description

The invention relates to a process for the preparation of / j'-aminoethyl aromatics. It is known, / j'-Phenylethylamine by hydrogenating Obtain benzyl cyanide in liquid ammonia (Org. Synth., Coil. Vol. 3, p. 7200 f. [1955]). the However, the production of alkylated or arylated / i'-amino aromatics on the nitrogen is still required Much greater effort, since starting from // - phenylethylamine by alkylation with alkyl halides or reaction of its benzene compound with alkyl halides and alcohols can be won. It is also known, // - Aminoäthylgruppen directly into an aromatic System to be introduced by optionally alkylated or arylated aziridines on the nitrogen atom is assumed (G. J. Bras, Ber. Akad. Wiss. USSR, 87, 589). However, these known methods have distinct disadvantages because they are technically very expensive or, in the case of aziridines, the starting materials in the monomer state are not resistant and are also known to be particularly dangerous respiratory and skin giflc are.

A process for the preparation of / j'-aminoethyl aromatics has now been found, which is characterized is that one Oxazolidone- ^) of the general formula

R ²

3 °

where R ¹ to R ^:! Hydrogen, alkyl radicals with 1 to 4 carbon atoms and R ^{: i} additionally denotes an aromatic radical and the radicals indicated can be identical or different, on aromatic hydrocarbons of the general formula

40

where R 'to R ^{(i denote} hydrogen, alkyl radicals having 1 to 4 carbon atoms and the radicals indicated can be identical or different, in the presence of at least equimolar amounts, preferably 1.2 to 2.5 mol, based on the oxazolidone used - (2), on Friedel-Crafts catalysts at a temperature in the range from 50 to 250 ° C. in the liquid phase, optionally with the addition of a solvent which is inert under the reaction conditions.

This method is new and has not yet been described in the literature. It has the advantage that the raw materials used are stable, easily accessible and non-toxic.

Oxazolidone- (2) suitable for the implementation are preferably unsubstituted compounds on the ring carbon atoms, e.g. B. oxazolidone- (2), 3-methyl-oxazolidone- (2), 3-ethyl-oxazolidone- (2), 3-p-pyl- and 3-isopropyl-oxazolidone- (2), 3-butyl-oxazolidone- (2), 3-Phenyl-oxazolidon- (2), 3-o- (m-, p-) tolyl- () xazolidon- (2), furthermore you can still use the ring carbonates substituted oxazolidones- ^), such as f> 5 4 - methyl - oxa / .olidone - (2), 4,4-dimethyl - oxazolidone - (2), 3 - methyl - 4,4 - dimethyl - oxa / .olidone - (2), 3-phenyl-4,4-dimethyl-oxa / olidone- (2), 5-methyloxazolidone - (2), 5,5 - dimethyl - oxazolidone - (2), 3 - methyl - 5,5 - dimethyl - oxazolidone - (2), 3 - phenyl-5,5-dimethyl-oxazolidone- (2), be used.

Suitable aromatic hydrocarbons are benzene and straight or branched chain ones lower alkyl radicals monosubstituted benzenes, such as toluene, ethylbenzene, propylbenzene, isopropylbenzene, Butylbenzene, 2 and 3 times substituted by straight or branched chain alkyl radicals Benzenes, where the substituents can optionally be mixed, such as o-xylene, m-xylene, p-xylene, o-, m- and p-diethylbenzene, the corresponding propyl, isopropyl, butyl and isobutylbenzenes, Mesitylene, pseiidocumene, hemillitol, p-cymene or o-, m-, p-ethyl toluene, in question.

The use of catalysts of the Friedel-Crafls type, such as, for. B. AlCLi, FeCl. !, ZnCls. BFa. The amount of catalyst can be varied within wide limits, but at least 1 mol of catalyst to 1 mol Oxazolidone- (2) must come. It is expedient to use 1.2 to 2.5 moles of catalyst per mole Oxazolidone- (2).

The reaction is carried out at a temperature of 50 to 250.degree. C., preferably 80 to 200.degree. However, the temperature should be chosen so high that .sich from the oxazolidone (2) used in each case CO2 to be split off in a reasonable Time splits off.

The reaction takes place in the liquid phase. Provided it is possible that the aromatic hydrocarbon used for the reaction is used as a solvent at the same time used. For this purpose it is used in a 2 to 2 () fold excess. But it is also possible to use a solvent suitable for F'riedel-Crafts reactions, such as. B. Ligroin, CS ^, nitrobenzene. This is then in used in such amounts that the reactants are sufficiently dissolved.

In one way of carrying out the process according to the invention, the catalyst is combined with a 5- to 20-fold excess of the aromatic hydrocarbon, based on the oxazolidone- (2), placed in the reaction vessel equipped with a good stirrer. This is where appropriate the oxazolidone (2) was added in portions with external cooling. Then it will be like that heated for a long time until the evolution of gas has ceased. The amine formed in the reaction is after known methods worked up. For example, acid-insoluble organic substances are separated off Share by pouring the reaction solution into water or dilute acid. After separation and purification of the aqueous phase, this is made alkaline and the free base is removed Filtration or extraction isolated.

Those produced by the process of the invention Products are used in pure form or in the form of their salts as pharmaceuticals or bactericides used.

example 1

160 g (1.2 mol) of AlCIa with 250 ml of dry Benzene covered and with cooling and thorough stirring in portions with 87 g (1.0 mol) of oxazolidone (2) offset. The mixture is then refluxed for 12 hours. The approach is then in 1 1 of a mixture of equal parts 10%

HCl and ice entered. The aqueous acidic phase is extracted with 200 ml of ether and 25% NaOH is added until the aluminum hydroxide has completely dissolved. Extraction with ether gives a basic reaction product which, in the fractional distillation, 28 g (23 ¹¹ O of theory) of p'-phenylethylamine as a colorless liquid with a boiling point of 75 to 77 C / 10 Torr and /; = 1.5332 returns.

The product is IR-identical to authentic / j-phenylethylamine.

160 g

Example 2
[1.2 moles) AlCly, 300 ml p-xylene and 87 g

(1.0 mol) Oxazolidon- (2) are as in Example 1 implemented and heated to 140 C for 8 hours. An analogous work-up gives 1,4-dimethyl-2- (2'-aminoethyl) benzene as a colorless liquid with a bp. 107 to 109 C / K) Torr.

Example 3

53 g (0.4 mol) of AlCl ₃ , 250 ml of benzene and 28.5 g (0.2 mol) of 3-n-butyl-oxazolidone- (2) are reacted according to Example 1; Reflux period 12 ¹ ^ hours. Work-up yields 4.9 g (14% of theory) of n-butyl- / i-phenylethylamine as a colorless liquid with a boiling point of 70 ° C. 0.3 Torr and η = 1.5003.

Example 4

89 grams (0.66 moles) of AlQi. 250 ml of benzene and 55 g (0.33 mol) of 3-phenyl-oxazolidone- (2) are refluxed according to Example 1 for 47 hours. 46.0 g (70 ¹ V ₁₁ of theory) of N-phenylv-phenylethylamine are obtained as a colorless liquid with a boiling point of 106 C 0.05 Torr, η = 1.6016.

Boiled under reflux for 20 hours according to Example 1 and worked up according to Example 5. 31g are obtained (44% of theory) N- [p-tolyl] - / i'-phenylethylamine as a colorless liquid with a boiling point of 120 to 121 ° C. 0.01 torr.

Example 7

58.5 g (0.33 mol) of 3- [p-tolyl] oxazolidone- (2). 89 g (0.66 mol) of AlCIy and 250 ml of toluene are added Example 1 Boiled under reflux for 15 hours and worked up according to Example 5. The yield is after two distillation, 22 g (29% of theory) of N- [p-tolyl] - / i-lolylethylamine in the 130 boiling range to 140 C. 0.01 torr.

The product is a mixture of isomers (cf. Example 5) in which the p-isomer strongly predominates.

Claims (1)

Claim: Process for the production of ί-aminoethyl aromatics. characterized, that one Oxazolidone- (2) of the general formula R ² 35 Example 5 55 g (0.33 mol) of 3-phenyl-oxazolidone- (2), 89 g (0.66 mol) of AlO: i and 250 ml of absolute toluene are used heated to reflux according to Example 1K) hours. The approach is then immediately in 1 1 20 "» ige KC) H entered and worked up by extraction with ether as usual. One obtains through fractionated Distillation 39 g (55 "/ n of theory) of pure N-phenyl - /; - tolylethylamine as a colorless oil from Bp. 120 to 128 C / 0.1 Torr. The product consists of an isolation mixture with respect to that of the Toluene-derived methyl group. B e i s ρ i e 1 6 58.5 g (0.33 mol) of 3- [p-tolyl] oxazolidone- (2), 89 g (0.66 mol) of AlCly and 250 ml of absolute benzene where R ¹ to R ^:! Hydrogen, alkyl radicals with 1 to 4 carbon atoms and R ^{: i} also denotes an aromatic radical and the radicals indicated can be identical or different, with at least equimolar amounts of aromatic hydrocarbons of the general formula R ⁴
R ⁵
R ⁶ where R 'to R ^{11 are} hydrogen, alkyl radicals with 1 to 4 carbon atoms and the specified radicals can be identical or different, in the presence of at least equimolar amounts, preferably 1.2 to 2.5 mol, based on the oxazolidone ( 2). on Friedel-Crafts catalysts at a temperature in the range from 50 to 250 ° C. in the liquid phase, optionally with the addition of a solvent which is inert under the reaction conditions.