DE941288C - Process for the preparation of substituted 2-imino-4-thiazolines or of salts thereof or of substituted 2-aminothiazoles - Google Patents

Description

Process for the preparation of substituted 2-imino-4-thiazolines or of salts of the same or of substituted 2-aminothiazoles It has been found that you can easily substituted 2-imino-4-thiazolines or salts thereof as well as substituted 2-aminothiazoles can be obtained by using an enolizable α-rhodanecarbonyl compound with a primary amine or one formed from a primary amine and an acid Salt mixes with the exclusion of water, the mixture is heated and that at the onset Reaction eliminated water removed from the mixture, whereupon a obtained salt of a substituted 2-imino-q.-thiazoline in the presence or absence an aqueous mineral acid heated or neutralized in the usual way and continue optionally heated a free substituted 2-imino-4-thiazoline base obtained will.

In this reaction, the hydroxyl group of the enol form of the a-rhodanecarbonyl compound and a hydrogen atom of the amino group of the primary amine are first split off as water, an inconsistent intermediate product being formed in which the nitrogen atom of the amino group of the amine is bonded to the carbon atom of the original carbonyl group of the carbonyl compound . In this intermediate product, ring closure then takes place between the amino nitrogen atom and the carbon atom of the rhodane group with migration of the remaining hydrogen atom of the amino group to the rhodane nitrogen atom, a 2-imino-4-thiazoline being formed which has the following constitution In terms of structure, the course of the reaction is as follows In this reaction scheme, R1 and R2 denote the non-reactive radicals of the α-rhodanecarbonyl compounds and R3 denotes an organic radical which is bonded to the amino group of the primary amine. In general, R 1 and R 2 are hydrogen or hydrocarbon radicals containing from 1 to 10 carbon atoms, while R 3 is a hydrocarbon radical having from 1 to 10 carbon atoms.

It is generally preferable when carrying out the reaction to use an amine salt of an acid, since: this leads to the formation of the corresponding acid salt of 2-imino-4-thiazoline, which is generally in the anhydrous reaction medium is insoluble and, as a result, is easily isolated in excellent yield can. The latter compound can then be easily quantified by neutralization convert to the free iminothiazoline base. The application of the hydrochloride of the amines. as acid salts is technically advantageous, but you can use other hydrohalides, z. B. the hydrobromides and hydroiodides, and other salts of amines with acids, z. B. with sulfuric acid, phosphoric acid and other mineral acids.

If a free amine is used in the reaction, the 2-imino-4-thiazoline free base which forms is difficult to igolate because of its solubility in the reaction mixture and because it rearranges easily on heating to form the tautomeric, more stable 2-aminothiazole Accordingly, when a free amine is used, a 2-aminothiazole can also be obtained as a process product in the distillation of the reaction mixture after the reaction according to the invention.

So that the procedural conditions are met with certainty it is advisable to use a mixture of the rhodanecarbonyl compound and the primary amine or its hydrochloride with a substantially anhydrous organic diluent which forms an azeotropic mixture with water, and then heats the mixture with azeotropic abortion of the water under reflux. The amount of abortion Water is also a measure of the degree of conversion up to which the reaction is advanced. Suitable organic diluents which are azeotropic with water Form mixtures and boil between 50 and 100 degrees, a suitable temperature range to carry out the reaction are, for. B. 'Benzene, toluene, amyl alcohol, isoamyl alcohol, n-butyl alcohol, isobutyl alcohol, secondary butyl alcohol, tertiary butyl alcohol, ethyl acetate, Propyl alcohol and mixtures of alcohol and carbon tetrachloride, Trichlorethylene and alcohol, trichlorethylene and allyl alcohol, trichlorethylene and n-propyl alcohol, Alcohol and ethyl acetate, alcohol and benzene, butanol and benzene, allyl alcohol and Benzene, n-propyl alcohol and benzene, benzene and heptene and the like.

However, it is also sufficient to heat the anhydrous reactants alone in an open vessel at such a temperature; that the vapor pressure of the water sufficient to remove it, e.g. B. at 5o to ioo ° to the one described above To allow reaction to occur.

Any enolizable a-rhodanecarbonyl compound can be used as a reactant according to the invention, ie a-rhodanaldehydes or a-rhodanecetones of the general formula where R, and R2 denote hydrogen or hydrocarbon radicals. However, R 1 and R 2 can also be radicals which, in addition to carbon and hydrogen, contain other elements in non-reactive form, e.g. B. hydrocarbon radicals in which hydrogen is replaced by halogen or by groups in which hydrocarbon radicals are bonded via ether-like oxygen or sulfur atoms, or by nitro groups. All of these α-rhodanaldehydes and ketones are known and can be easily prepared by known methods, e.g. B. by reaction of sodium rhodanide with a-Halogena.Idehyden and ketones.

. Suitable starting compounds of the a-rhodanaldehydes are a-rhodanacetaldehyde and its homologues and substitution products, from the a-rhodan ketones e.g. B. 3-Rhodanpropanon- (2), 3-Rhodanbutanone- (2) and their saturated and unsaturated homologues and substitution products.

a-Rhodanketones, in which the radical R, of the above general formula is a hydrocarbon radical are, because of their easy accessibility, as reactants particularly suitable.

The primary amines or used as the second reactant their salts can be unsubstituted and have a heterocyclic ring-shaped structure be. You can have substituents such as halogen atoms, nitro groups, ether and thioether groups and other hydrogen-free, non-reactive groups. Also primary amines, the hydroxyl, mercapto, carboxyl, sulfonic acid and others containing hydrogen Groups included are usable.

In particular, methylamine, ethylamine and theirs come into question for this Homologues and substitution products, allylamine and its substitution products, Cyclohexylamine, Cyclopentylamine, Aniline, Toluidine, Diphenylamine, Naphthylamine, Benzylamine and its known substitution products. As substituted amines are z. B. to mention 2-Amino-furan, 2. Amino-dioxane (i, 4), 3-Amino-y-pyran, 2-aminopyridine, 2-aminothiazole, 2-amino-a-methyl-4-phenyl-5-thiazole acetic acid, 3-amino-thiophene, 4- (aminobutyl) piperidine.

Many of the 2-imino-4-thiazolines and their salts with acids, which are obtained according to the invention, are new compounds that are used as accelerators and activators in rubber vulcanization and as intermediates for the synthesis of other vulcanization accelerators, as drugs and drug intermediates, as pesticides with insecticidal, fungicidal and herbicidal properties are used. Such new 2-imino-4-thiazolines or their salts, which are particularly useful in the rubber industry, correspond to the general formula where R 1 and R 2 are hydrogen or alkyl, while R 3 is alkyl or aryl and the total number of carbon atoms in the R groups is at least 3. Compounds of this type are useful for the synthesis of vulcanization accelerators and are accelerators themselves. They are particularly valuable accelerators when R3 means aryl. If R3 is an oxy, carboxy, mercapto, amino or sulfonic acid-substituted alkyl or aryl group, the effectiveness of the accelerator is modified. For example, the compounds in which R3 is acidic in nature, e.g. B. contains a carboxy or sulfonic acid group, due to the acidic group retarding effect, while compounds in which R3 contains an amino or mercapto group, have accelerating effect due to their own activating group.

In the following examples, parts mean parts by weight. Example i 25.8 parts of a mixture of rhodanebutanones, prepared by reacting sodium rhodanide with a mixture of 3-chlorobutanone- (2) and i-chlorobutanone- (2), obtained in the chlorination of x moles of methyl ethyl ketone with 1 mole of chlorine 85 weight percent 3-rhodan butanone (2) and 15 weight percent i-rhodan butanone (2), a benzene solution containing 26 parts of aniline hydrochloride and 87 parts of benzene, in a reaction vessel equipped with a stirrer, a water separator and a thermometer for measuring the temperature in the reaction zone is added. The mixture was heated to approximately 80 ° with stirring. The reaction mixture was held at 80 ° until 3.6 parts of water were azeotroped off, which took approximately 3 hours. When no further azeotropic water-benzene mixture appeared in the reflux, the reaction mixture was cooled to 20 °, taken out of the reaction vessel and filtered in order to isolate the precipitate formed. The latter was washed once with benzene and twice with acetone and then dried. In this way, 46.1 parts (corresponding to 96% of theory) of a solid substance with a melting point of 220 ° to 225 ° were obtained. This mixture contained 3 g, 2 parts, that is 850 / "2-imino-3-phenyl -4,5-dimethyl-4-thiazoline hydrochloride and 6.9 parts, that is 15%, 2-inuno-3-phenyl -4-ethyl-4-thiazoline hydrochloride.

Example 2 A solution of 26 parts of aniline hydrochloride in 79 parts of benzene and 8 parts of n-butanol and 2.5.8 parts of a mixture of rhodanebutanones, as described in Example i, were combined in a reaction vessel of the type also described in Example i Heated 800 until 3.6 parts of water had been azeotropically driven off. The resulting mixture was cooled to room temperature and the precipitate formed was filtered off, washed once with benzene and twice with acetone and then dried. 37.1 parts of a mixture of 2-imino-3-phenyl-4-thiazoline hydrochloride compounds, consisting of 85% 2-imino-3-phenyl-4,5-dimethy1-4-thiazoline hydrochloride and 159,2-imino, were obtained -3-phenyl-4-ethyl-4-thiazoline hydrochloride. The mixture had a m.p. = 220 to 225 °. EXAMPLE 3 26 parts of aniline hydrochloride and 25.8 parts of the rhodanebutanone mixture from Example i were heated in the presence of 44 parts of benzene and 34 parts of heptane as diluents at about 0 ° until 3.6 parts of water had been driven off azeotropically. The resulting mixture was cooled to room temperature and, after filtration, the precipitate was washed once with benzene, twice with acetone and finally dried. 43.7 parts of a mixture of 2-imino-3-phenyl-4-thiazoline hydrochlorides containing 85% imino-3-phenyl-4,5-dimethyl-4-thiazoline hydrochloride and 15% 2-imino were obtained -3-phenyl-4-ethyl-4-thiazoline hydrochloride. Example 4 In the presence of 7 g parts of benzene and 8 parts of n-butanol, 26 parts of aniline hydrochloride and 25.8 parts of 3-rhodanebutanone- (2) were heated at 800 until 3.6 parts of water had been driven off azeotropically. The resulting mixture was cooled to room temperature and the precipitate formed was filtered off. It was then washed once with benzene and twice with acetone and then dried. 41 parts were obtained (corresponding to 80% of theory) with a m.p. = 225 to 243 °. A sample of the product was purified by recrystallization from alcohol. The purified substance had a F. = 239 to 241 °. A sample of this was analyzed. Calculated for C "H1sN, SC1 in%: C 55.0o, H 5.40, N ii, 6o, S 13.30, Cl 4.70; found in C 5490, H 5.46, N 11.64, S 13.29, Cl 14.77 The analysis shows that the values found agree with those calculated for C11 H13 Na S C1 Part of the compound was neutralized with aqueous sodium hydroxide solution, which is a substance insoluble in water From this free base and, for comparison, from compounds of similar constitution, such as 2-aniline-4,5-dimethylthiazole, 2-thiono-3-phenyl-4,5-dimethylthiazoline, 2-amino -4, 5-dimethylthiazole and 2-mercapto-4,5-dimethylthiazole, absorption curves in the ultraviolet light were recorded. The absorption curves of the compound obtained according to the method differed significantly from those of the other compounds, although there is a certain similarity in the course of the curve of 2-mercapto-4, 5-dimethylthiazole and 2-thiono-3-phen yl-4,5-dimethylthiazoline at about the same wavelengths, while on the other hand 2-amino-4,5-diinethylthiazole and the free base described above also have absorption maxima at about the same but different wavelengths. The absorption maxima of 2 = thiono-3-phenyl-4,5-dimethylthiazoline and the free base mentioned are at a lower wavelength range; In the case of 2-thionothiazoline, the reason for this is apparently the presence of the phenyl group in the 3-position. The course of the absorption curves of the free base and of the 2-anilino-4,5-dimethylthiazole, however, had no similarity.

Ultraviolet analysis provides convincing evidence that the compounds 2-imino-3-phenyl-4,5-dimethyl-4-thiazoline hydrochloride and its free base, 2-imino-3-phenyl-4,5 dimethyl-4-thiazoline. The free base is a crystalline solid with a melting point of 52 to 53 °. The ultraviolet absorption spectra of the compound show an absorption peak of 261 A, at 33.5 Ex, ax. Example 5 26 parts of 3-rhodanebutanone (2) and 25.8 parts of aniline hydrochloride were heated together to 95 ° for 4 hours in an open vessel, a solid product being formed. This was dissolved in a benzene-ether mixture, the ether was driven off and the crystalline precipitate was dried. 24 parts of 2-imino-3-phenyl-4,5-dimethyl-4-thiazoline hydrochloride with a melting point of 239 to 242 ° were obtained.

The following example illustrates the reaction of a rhodanecarbonyl compound of the type described above with a free primary amine in such a way that a 2-aminothiazole was prepared by distillation of the resulting reaction mixture, the aminothiazole under the action of heat during the distillation by tautomerization of the as 2-imino-4-thiazolines formed as intermediate product. Example 6 93 parts (i mole) of aniline. 2.8 parts of anihydric chloride, 64.5 parts (1/2 mol) of 3-rhodanebutanone- (2) and 175 parts of benzene were heated together in a reaction vessel at 80 for 3 hours until the water formed during the reaction was 8.5 parts , was azeotropically driven off with benzene. The excess of benzene and unreacted aniline was then removed by distillation under reduced pressure using a water pump. The remaining residue was distilled at an absolute mercury pressure of 0.1 to 0.4 mm, yielding 72 parts of a colorless, crystalline product from F. = io1 to 1o5 ° and a resinous tar was produced as the distillation residue. The white crystalline substance in the distillate was purified by recrystallization first from a mixture of alcohol and benzene and then from alcohol. The purified product was a colorless crystalline substance of diamond-like crystal form and an F. = 107 to = 9.5 °. It was identified as 2-anilino-4,5-dimethylthiazole by ultraviolet absorption values. The following chemical analysis values are consistent with those calculated for this compound. Calculated for 2-aniline-4,5-dimethylthiazole in 0/0 C 64.67, H 5.92, N 13.71, S 15.69; Found in 0/0 C 64.64, H 5.91, N 3.67, S 15.71. Examples 7-13 In Examples 1-5 above, the reactants were used in substantially equal proportions. Likewise, the reaction temperature used was consistently 80 ° when the reaction was carried out in the presence of an azeotropic solvent. These reaction conditions are not strictly limited; rather, the proportions of the reactants and the reaction temperature can be varied with essentially the same results. The following examples in the table are also intended to show how the process according to the invention can be modified. Tabel Share reactant reaction conditions Yield to Example Io Aniline- 3-Rho- reaction tempe- parts 2- -3-phenY1-4 , 5-di- No. Hydro- dan-bu- azeotropic time ratur ab- methyl-q.-thiazoline-hydro- chloride tanon- (2) solvent in hours ° C driven chloride in ° / o water 7 7I, 2 6.45 no 2.0 go no 20.0 8 77.6 64.5 175 parts benzene 3.3 = o6 8.2 78 0 9 64.8 64.5 175 parts benzene and 40 parts of n-butanol 4.25 84 8.8-78.2 1o 64.8 64.5 175 parts benzene and 40 parts of n-butanol 5.15 85 8.6 83.7 i = 66, o 64.5 194 parts of benzene and 20 parts of n-butanol 3.0 82 8.4 89.5 12 = 31.0 129.0 345 parts benzene and 80 parts of n-butanol 3.25 85 18.4 75.0 13 = 31.0 129.0 39o parts benzene and 40 parts of n-butanol 4.0 81 18.0 8I, 6 The following Example 14 shows the best procedure for carrying out the process for the preparation of .2-imino-4-thiazoline compounds according to the invention and illustrates a further modification of the procedure according to the invention. Although in this example the procedure is described in detail using aniline hydrochloride and a mixture of rhodan butanones [850 /, 3-rhodan butanone (2) and 15% 1-rhodan butanone (2)] as reactants, the working conditions and Process steps are applicable to any combination of respondents and generally give the best results. Example 14 A mixture of 18.1 parts of benzene, 0.67 parts of n-butanol (corresponding to a ratio of 27 parts of benzene to 1 part of butanol), 2.87 parts of aniline hydrochloride, 2.43 parts of 3-rhodanebutanone (2) and 0.43 parts of I-rhodan butanone (2) were heated to 80 ° with stirring in a reaction vessel equipped with a heating mantle, a stirrer and a water separator. This temperature was maintained until 0.4 parts of water had been azeotropically removed, which took 5.3 hours. The heating was then interrupted and the resulting slurry was extracted with = 3 parts of water. After the water extraction, the benzene and water layers were separated and the benzene layer was extracted again with water. After the benzene layer was extracted three times, using equal amounts of water for each extraction, the benzene was distilled off. All three water extracts were combined and the butanol removed by azeotropic distillation. A sample of the aqueous solution that remained in the distillation vessel contained 13.83% alkyl-2-imino-4-thiazoline hydrochlorides, which meant a total yield of 5.3 parts of these hydrochlorides on a dry basis, i.e. a yield of 99.5% 0. The 2-imino-4-thiazoline hydrochlorides formed in this reaction were 2-imino-3-phenyl-4,5-dimethyl-4-thiazoline hydrochloride (85%) and 2-imino-3-phenyl-4-ethyl-4-thiazoline hydrochloride (15%). A mixture of the free bases of these iminohydrochlorides can easily be obtained by neutralizing the mixture of hydrochlorides with sodium hydroxide, for the free bases are insoluble in water and can be isolated in any suitable way.

The following Examples 15-28 illustrate the use of various reactants different from those of the preceding Examples, correspondingly forming different compounds. Example 15 Using the procedure of Example r, 67 parts of methylamine hydrochloride, x29 parts of 3-rhodanebutanone- (2) were reacted in the presence of a diluent of 196 parts of benzene and 20 parts of n-butanol until 18 parts of water were azeotropically distilled off. The resulting mixture was cooled to room temperature and filtered. The solid precipitate obtained was washed once with benzene and twice with acetone and then dried. 153 parts of 2-imino-3, 4, 5-trimethyl-4-thiazoline hydrochloride were obtained, that is a yield of 86%. After purification by recrystallization from alcohol, the substance had an -F. = 282 to 283 °. It was found to be the above compound by chemical analysis, the values of which are given below. Calculated in ° / o: C 40.33, H 6, zo, N 15.68, S 17.94, Cl 19.84; found in 0 / ,: C 40.35, H 6.4, N 15.67, S 18, o6, Cl 19.87. Example 16 A solution containing 64.5 parts of 3-rhodanebutanone (2), 41 parts of ethylamine hydrochloride, 261 parts of benzene and 20 parts of n-butanol was heated to boiling with stirring and reflux until 9 parts of water had been driven off azeotropically . The reaction mixture was then cooled to room temperature and the precipitate formed was filtered off. 82.5 parts of a dry, solid substance were obtained in a yield of 86% with a melting point of 226 ° to 232 °. This melted after recrystallization. Alcohol at 236 to 238 ° and was identified by the following analysis results as 2-imino-3-Ä.thyl-4,5-dimethyl-4-thiazoline hydrochloride. Calculated in ° / o: C 4367, H 675, N 14.54, S 1.6164, Cl 18.4o; found in ° / o C 43.53, H 6.76 "N 14.62, S x6.72, Cl x8.39. When the compound obtained was neutralized with a base such as sodium hydroxide, potassium hydroxide or calcium hydroxide, the free base 2-irnino-3-ethyl-4,5-dimethyl-4-thiazoin.

Example 17 2s, 8 parts of 3-rhodanebutanone (z) and 38 parts of 5-amino-salicylic acid hydrochloride were suspended in a M1 mixture of 183 parts of benzene and 40 parts of n-butanol and then heated to 78 to 80 ° for 6 hours, the water of reaction being driven off azeotropically. The resulting mixture was cooled and the gray, crystalline precipitate was filtered off. The latter was washed with a benzene-hexane mixture and then uricrystallized from alcohol. 54 parts of a white crystalline substance with a melting point of 279 to 28 ° were obtained. Analysis of a sample gave the values given below, which agree with the values calculated for 2-imino-3- (3'-carboxy-4'-oxyphenyl) -4, 5-dimethyl-4-thiazoline hydrochloride.

Calculated in ° / o H 4.36, C 47.92, N 9.32, S 10.66, CI 11.78, O 15.96; found in ° / o H 4.41, C 48.13, N 9.33, S 10.63, Cl 11.70, O 15.8o (as the difference). -This analytical result was also supported by an ultraviolet spectrogram.

Example 18 -32.3 parts of 3-rhodanebutanone- (2) and 33.0 parts of cyclohexylamine hydrochloride were in a mixture of 7 parts of n-butanol and 183 parts of toluene in the example i described reaction device suspended. The suspension was then. approximately Heated for 7 hours to 1o6 °, 4 parts of water being azeotropically distilled .wurden. The slurry remaining in the reaction vessel was cooled and filtered. The raw one crystalline product was taken up with hot alcohol and recrystallized cleaned. The purified product had a m.p. = 243 to 245 °. A sample of the Product was analyzed for its chemical composition and another Sample subjected to ultraviolet spectrum analysis. The chemical analysis of the purified Product agreed with that for 2-imino-3-cyclohexyl-4,5-dimethyl-4-thiazoline hydrochloride calculated composition and gave the following values. Calculated in o% :.

C 53.53, H 7.76. N 11.35, S x 2.99, C 114.37 found at ° / o C 53.53, H 7178, N Iz, 39 @. S 12.98, Cl 14.40. The close correspondence of the chemical composition found by analysis on the one hand with the calculated one and on the other hand with that found by ultraviolet spectral analysis proved that the earth product was the above compound, Example 1g Ir a reaction device; As described in Example 1, 32.3 parts of 3-rhodan butanor- (2), 24.4 parts of monoethanolamine hydrochloride, 181 parts of benzene and 70 parts of n-butanol were introduced. The mixture was heated to 79 ° for 20 hours, during which. About 5 parts of water were removed azeotropically. After the slurry obtained had cooled, the crystalline product was filtered off and this was washed with acetone and dried. A yield of 48 parts of crude product, that is 92 "of theory, was obtained. The crude product was then dissolved in hot alcohol and, after concentration, was recrystallized by evaporating part of the alcohol. The purified product was a white crystalline substance with a melting point of 1 mg to 200 °. The chemical analysis gave the following values: 40.25% carbon, 6.35% hydrogen, 13.4% nitrogen, 17.0% chlorine and »7,620 /, (as the difference) oxygen; together with ultraviolet spectral analysis, it showed that the compound represented was 2-imino-3- (β-oxyethyl) -4,5-dimethyl-4-thiazoline hydrochloride. Example 2o 3- (β-chloroethyl) -2-imino-4,5-dimethyl-4-thiazolin._ hydrochloride was prepared by reacting 64.5 parts of 3-rhodanebutanone (2) and 58 parts of β-chloroethylamine hydrochloride in the presence of 137 parts of benzene and 32 parts of n-butanol at 80 ° until approximately g parts of water had been removed azeotropically in about 5 hours. The obtained slurry was filtered, the precipitate washed with benzene and acetone and dried. 112.5 parts (corresponding to 9 g% of theory) of a crude product with a melting point of 184 ° to 20 ° were isolated. After recrystallization from ethanol, it formed a colorless crystalline substance with a melting point of 207 ° to 211 °. The chemical analysis of this compound shown in the table below and the ultraviolet spectrum analysis showed that the desired compound was obtained. Calculated in 0/0: C 37.00, H 5.29, N 12.33, S 14.10, Cl 31.28; found in 0/0 C 36.99, H 5.22, N 12.32, S 14.12, Cl 31.25 .. Example 21 2-Imino-3- (o-oxyphenyl) -4,5-dimethyl -4-thiazoline hydrochloride was prepared by reacting 32.3 parts of 3-rhodanebutanone (2) and 36.4 parts of o-aminophenol hydrochloride in the presence of 183 parts of benzene and 32 parts of butanol at 75 to 7 g °, up to 4.5 parts of water removed azeotropically, which took about 2 hours. The resulting slurry was filtered and the filter residue was washed with acetone and dried. 59.2 parts (corresponding to 93% of theory) of the crude product with a melting point of 21 g to 232 ° were obtained.

In a similar way, methyl β-aminopropionate hydrochloride and 3-rhodanebutanone- (2) became 2-imino-3- (β-carbomethoxyethyl) -4,5-dimethyl-4-thiazoline hydrochloride of the formula from the F. = 157 to 15g ° and from p-nitroaniline hydrochloride and 3-rhodanebutanone- (2) the 2-zmino-3- (p-nitrophenyl) -4, 5-dimethyl-4-thiazoline hydrochloride of the formula obtain. F. = 266 to 268 °. The analytical values of the latter compound for C11 H12 N, 02 S Cl, calculated in%: C 46.23, H 4.23, N 14.71, S 11.22, Cl 12.41, O 11.2o (as the difference ); Found in 0/0 C 4594, H 4.25, N 14.42, S 11.10, Cl 12.27. In an analogous manner, 2-imino-3- (methoxypropyl) -4,5-dimethyl-4-thiazoline hydrochloride of the formula was obtained from 3-methoxypropylamine hydrochloride and 3-rhodanebutanone- (2) from the F. = 152 to 153 ° obtained with the following analysis values for C9 HI, N2 OS Cl.

Calculated in 0/0: C 4564, H 7.24, Ni 1.83, S 13.54, Cl 14.97, O 6.75 (as the difference); found in% C 45.52, H 7.22, N 11.82, S 13.47, Cl 15.1o, O 6.87 (as the difference). Next was the 3- (dimethylaminopropyl) derivative from. F. = 22o to 226 ° (in uncleaned condition) produced. For identification, this compound was converted into the benzoyl derivative, the 2 - iminobenzoyl - 3 - (dimethylaminopropyl) - 4,5 - dimethyl-4-thiazoline with the following structure of m.p. = 99.5 to 10 °, the elemental composition of which for C "H23N30S was the following. Calculated in 0/0: C 64.33, H 7.30, N 13.24, S 10, 10.0 5.04 (as the difference); found% C 64.32, H 7.35, N 1324, S 9.98, 0 5.11 (as the difference) A compound of the following structure was also prepared This compound has an F. of about 320 ° with decomposition. The following elemental composition was determined for C16HZOCl2N4S2. Calculated in ° / o N 13.89, Cl 17.58, S 15.90; found in% N i 3.91, Cl r 7.5 =, S Z 6.12.

Claims (3)

PATENT CLAIMS: 1. Process for the preparation of substituted 2-imino-4-thiazolines or salts thereof or: substituted 2-aminothiazoles, characterized in that an enolizable α-rhodanecarbonyl compound is used with a primary amine or one of a primary amine and an acid The salt formed is mixed with the exclusion of water, the mixture is heated and the water which is split off during the reaction which occurs is removed from the mixture, whereupon a salt of a substituted 2-imino-4-thiazoline obtained is optionally heated in the presence or absence of an aqueous mineral acid or in the usual way Way neutralized and further, if necessary, a free substituted 2-imino-4-thiazoline base obtained is heated. 2. The method according to claim 1, characterized in that the reaction is carried out in an organic diluent which forms an azeotropic mixture boiling between 50 and = oo ° with water, and the water formed in the reaction is removed by azeotropic distillation. 3. The method according to claim 2, characterized in that the reaction is carried out in, a liquid hydrocarbon performs.