DE1918058C - Process for the preparation of alkyl 1 alkenyldi and trisulphides - Google Patents

Description

It is a wide variety of organic disulfides and Trisulfide known. For these, both the symmetrical and the unsymmetrical are saturated and unsaturated disulfides, such as dimethyl sulfide, dimethyl trisulfide, dipropyl disulfide, methyl propyl disulfide, methyl propyl trisulfide, Diallyl disulfide, allyl propyl disulfide or methyl allyl disulfide typically. These connections can be readily prepared by a variety of synthetic routes. Until now, however Not yet a good synthetic route for alkyl-1-alkylene disulfides and trisulfides have been found.

The previous manufacturing processes for unsaturated Sulphides have generally been oxidation reactions using appropriately substituted mercaptans by means of iodine or exchange reactions between a suitable mercaptan and allyl mercaptan. It However, it has been shown that these routes as well as the direct attempts to isomerize the corresponding Allyl compounds for the production of 1-alkenyl compounds are unsuitable. In H ο u b e η— W e y 1, Methods of Organic Chemistry, Vol. 9 (1955), p. 139, it is stated that the reaction of sulfenyl chloride with a Grignard compound Diphenyl sulphide can be obtained, but this information is solely due to the production of aromatic thioethers, d. H. on compounds that contain only one sulfur atom between the aryl esters, limited. The same applies to the method described in German Auslegeschrift 1 169 439 for the production of vinyl sulfenyl halides. Notes on making connections that use a heterobridge consisting of two or three sulfur atoms contained, but are not found in these publications.

A process for the preparation of alkyl-S 1-alkenyl disulfides and trisulfides of the general formula

R ₁ R ₂
RS (S) _n C = CR ₃

in which R and R _{3 are} alkyl radicals. R ₁ and R _{2 represent} hydrogen atoms or alkyl radicals and ηϊ or 2 is found, which is characterized by the fact that an alkyl sulfur halide of the general formula

RS (S) _n X

in which X denotes a halogen atom, with an alkene of the general formula

Ki K ₂

MC = CR ₃

in which M is lithium, -MgBr or -MgCl, reacts at temperatures below room temperature. Alkyl-1-alkenyl disulfide and trisulfides can thus be prepared by directly using an alkali metal alkene or an alkaline earth metal alkenyl halide with an alkyl-substituted disulfur or trisulfur halide implements. The reaction can be represented by the following equation:

R ₁ R ₂

R ₁ R ₂
RS (S) _n X + MC = C - R ₃ - * RS (S) _n C = C- R ₃ + MX

In the formulas, R and R ₃ denote alkyl radicals, while R ₁ and R _{2 represent} hydrogen atoms or alkyl radicals. Particularly suitable alkyl radicals are lower alkyl radicals, such as methyl, ethyl, n-propyl, isopropyl, butyl, sec. Butyl or n-pentyl radicals. X represents a halogen atom, preferably a chlorine or bromine atom, while M represents MgBr, MgCl or lithium, preferably MgBr, and is n \ or 2. Typical of the sulfides used as starting materials are methyl disulfur chloride, methyl trisulfur chloride, ethyl disulfur chloride, n-propyl disulfur chloride, n-propyl trisulfur chloride, n-pentyl disulfur chloride and the corresponding bromides. Preferred among these compounds are methyl disulfur chloride, n-propyl disulfur chloride, methyl trisulfur chloride and propyl trisulfur chloride. Most preferred are compounds in which R ₁ and R 1 represent hydrogen atoms and R _{3 is} the methyl radical.

Reaction I is highly exothermic and is preferred carried out in the cold and in anhydrous conditions. Temperatures below room temperature, preferably between about -80 and 10 ° C. are suitable. The reaction is preferably carried out in the presence a solvent carried out, whereby one generally leads to solvents with low freezing points engages. Such typical solvents are ethers such as diethyl ether, tetrahydrofuran and Diisopropylether, or hydrocarbons such as hexane, benzene or toluene. It has been found to be very poor in practice üls ga ^ iict turned out to be the solvent too use in which the propenyl magnesium compound itself has been prepared.

With regard to the relative amount of the starting materials used, it is preferred for economic reasons Reasons to work with stoichiometric amounts, although an excess of one or the other starting material may exist. As a result of the reaction, the desired alkyl-1-alkenyl disulfide is obtained in solution or - * risulfide. The reaction mixture can be separated, and the individual components can be isolated by conventional working methods such as distillation. The separation is preferably carried out by evaporating the solvent and separating the resulting crude oil chromatographic separation methods.

Both the lithium or magnesium alkenyl compounds and the alkyl disulfur or trisulfur compounds, which are used in the above reaction as starting materials are as those produced by known methods.

The alkyl disulfide halide is produced by reaction a suitable alkyl trisulfide with a strong halogenating agent produced. Sulfuryl chloride, chlorine and bromine are used as such preferred.

The trisulfides used as starting materials do not have to be symmetrically substituted. However, will the symmetrical substitution is very much preferred, since the cleavage of a symmetrical trisulfide only increases leads to two sulfur halides. In contrast, when using an unsymmetrical alkyl

trisulfide four isomers possible as starting material. The alkyl substitution is of course based on the nature of the alkyl radical of the in the according to reaction I. alkenyl sulfide formed. Preferred trisulfides are dimethyl trisulfide and di-n-propyl trisulfide, although you can just as easily use the diethyl, dibutyl, di-sec.-butyl and di-n-pentyl trisulfides can.

The alkyl di- or tri-sulfur halides can also by halogenation of a suitable alkylacetyl di- or trisulfide. Other halogenating agents such as those described above can also be used can be used. The reaction leads to the cleavage of the acetyl compound and gives the halogenated Di- or trisultide.

The reactions described above are preferably, best below room temperature between - carried out 35 and 40 ⁰ C. The reaction is preferably carried out in such a way that the halogenating agent is added to the sulfide without the use of a solvent. If desired, however, one can use one. Solvents such as hexane, benzene and isopentane are suitable for this purpose. With regard to the amounts of the starting materials, it is preferred for economic reasons to use stoichiometric amounts.

With these kcautioner, the di- or trisulfur halides are used obtained in solution and are then for the reaction with the substituted alkene according to Response 1 available. The starting materials used in the above reactions can all-cis, All-trans compounds or any combination represent the isomeric cis and trans forms.

Representative representatives of the compounds that are produced by the claimed process are:

Methyl- (2-methyl-propenyl) -trisulfide,

PropyI- (2-methyl-propenyl) -trisulfide,

Ethyl- (2-ethyl-propenyl) -trisulfide,

Methyl propenyl trisulfide,

Propyl propenyl trisulfide,

Ethyl propenyl trisulfide,

Methyl propenyl disulfide,

Propyl propenyl disulfide,

Methyl (2,2-dimethyl-propenyl) disulfide.

Propyl (2,2-dimethyl-propenyl) disulfide.

The substances can be in ice as well as in transForm are present or represent mixtures of the isomeric cis and trans forms.

The alkyl-1-alkaliyl disulfides of the invention are suitable for use as food flavorings. They have a characteristic aroma of cooked onions and can therefore give foods an onion taste. They are therefore suitable artificial seasonings for foods. With them, foods such as sauces, soups, purees, meat sauces, dips, sausage products and other foods which are to be given an onion taste and aroma can be treated.

The compounds are generally added in amounts of from 10 to 10 percent by weight, based on the weight of the total food to be treated. The respective amount depends on the individual taste of the individual consumer or, in the case of the large-scale production of food, on the average consumer. The substances can either be used alone or in combination with other disulfides, such as dialkyl disulfides. Dimethyl disulfide, dipropyl disulfide, methyl propyl disulfide, for example, may be mentioned as such; Additions of carriers such as vegetable oil, cottonseed oil, corn oil, starch, salt, sugar or gum arabic are also possible. In the mixture, they are suitably used in proportions of 0.01 to 20 percent by weight, the remainder consisting of carriers or other auxiliaries.

ίο The trisulfides are found to strengthen the through the Alkenyl disulfide developed taste, smell and aroma use to make a synthetic one Making onion seasoning mix that can give foods a two-flavored flavor that practically indistinguishable from that of natural products. They will usually be in touch with the alkynyl disulfide in 1 to 20, preferably 3 to 6 times the amount by weight of the alkenyl disulfide used used. The presence of these trisulfides gives a more developed flavor character. There are no other carriers or auxiliaries necessary, which can, however, be used if desired.

Suitable mixtures contain 0.005 to 20 percent by weight of the 1-alkenyl disulfide, 0.005 to 95 percent by weight of the 1-alkenyl trisulfide and 0.1 to 99.99 percent by weight of a carrier. They are zagesetzt foods geeigneterwei ^c e in sufficient quantity that a concentration of 10 ^-5 to 10 ^-2 Gewir!, Tsprozent, is obtained based on the total food to be treated. However, depending on the particular individual taste, you can also work with concentrations outside these ranges.

35

example 1

a) Production of propenyl lithium

Starting materials:

6.0 g (0.05 mol) 1-bromo-1-propene (distilled mixture of the cis and trans isomers),
1.1g (0.15g-atom) lithium wire (with low

Sodium content);
75 ml of ethyl ether (dried over sodium).

The reaction vessel, which consists of a 100 ml three-necked flask, a dropping funnel, a calcium chloride drying tube, a nitrogen tube, a stirrer and a reflux condenser, is thoroughly dried in vacuo at 105 ° C., allowed to cool, assembled and flushed with nitrogen. A slight positive nitrogen pressure is maintained in the reaction system throughout the subsequent reaction. This becomes a slurry

SS made from 1.1 g of finely cut lithium wire in 73 ml of ethyl ether is added to the reaction flask and stirred thoroughly. Then, / added about 20 ° ₀ of the 1-bromo-lpropens at a time, to bring the reaction. The start of the reaction is evident

by the reaction mixture becoming cloudy. The reaction mixture begins after a few minutes to reflux, whereupon the remainder of the bromide is added at such a rate that a moderate reflux is maintained. The overall

addition time is 35 minutes. The reaction mixture is then allowed to reflux for a further 45 minutes, cooled and under nitrogen until use kept.

5 6

Similar results are obtained when using be, whereby the corresponding η-butyl- or 1-chloro-1-propene are obtained in place of the 1-bromo-1-propene, n-pentyl-disulfur halides,
keep. b) The procedure of Example 1 is repeated ,,,. .. χ * _t ui λ -u hui -A with the exception that 2.06 g (0.0144 mol) of the n-Prob) production of methyl-d.schwcfelchlond ₅ pyi ^ sulfur chloride and 35 ml of the essential pro- Starting materials: penyllithium solution can be used. The Iso-5.5 g (0.044 mol) of dimethyl trisulfide (distilled); lierungsethods according to Example 5, 0.04 g of the 5.9 g (0.044 mol) of sulfuryl chloride (distilled). obtained cis and trans-n-propylpropenyl disulfides. the

Isomers are, as described above, separated and

The quartz equipment is analyzed individually for 1 hour at 105 ⁰ C in the io. The structure is made through analysis

Vacuum heated. After cooling, the by means of vapor-liquid chromatography and

Ground-joint compounds with 85% phosphoric acid mass spectrography in combination with NMR and

seals and confirms the entire system with dry chlorine IR spectroscopic values,

hydrogen gas purged. . .

The dimethyl trisulphide is then reduced to - 20 ° C - 15 H e 1 s ρ 1 e 1 J

cooled and mixed with the sulfuryl chloride. The a) Production of Äivyl-disulfur chloride

The reaction mixture changes its color almost completely.

indirectly into a red-orange. The mixture is left with _{6 g (Qm Mo]) of diethyl} . _tr j _S ulnd (distilled);

then warm to OC whereupon that during the _{5 9 (Qm U]) Sulfurvlch} i _ori d (distilled).

Reaction formed sulfur dioxide in a slight vacuum ao

Will get removed. Then the reaction die. Production takes place according to Example 2 with the

mixed distilled and the methane sulfenyl chloride in the exception, oass the reaction at - 30 ⁰ C vorgenom-

a dry ice-isopropanol trap at 25 ° C / fo mm is men. The first fraction becomes up to 30 ° C / 13 mm

Hg collected. The methyl disulfur chloride is collected in Hg. The ethyl-dhsulfur chloride is at

collected in a quartz receptacle at 29 to 30 ° C / 12mm 05 30 to 32 ° C / 13 mm Hg.

^Hg ^ position of methyl propenyl disulfide Manufacture of ethyl propenyl disulfide

To 0.93 g (0.008MoI) methyl disulfur chloride starting materials:

(CH ₃ SSCl), which has ^{cooled to -3O 0} C, 3.58 g (0.278 mol) of ethyl disulfur chloride;
25 ml of an ethereal propenyl-lithium solution with 30 40 ml propenyl-lithium in ether according to Example la), given in rapid succession of drops. The reaction mixture _. ,,,. . . _N η ■ ■ 11 u m _W, then approximately 25 ml of cold (10 ⁰ C) 0.1 N Salzsä'ure overall £, ese compound is prepared according to Example 1, giving, - ■. After separating the layers, the Be. the under-extracted by pampf liquid chromatography aqueous phase three times with 10 ml of ^{ethyl ether and} mass spectrography. The combined ether extracts are washed with 35% * "" ⁶ % of the two compounds with the MoIe-25 ml of 0.1N hydrochloric acid and determined over kulargev ^ cht 134, the es- and trans-ethyl anhydrous sodium sulfate are dried. After Oer decision P'openyl-disulnde you represent are as Beifernung the solvent, a dark brown oil ^s P ^{ld 2} beschneben is collected and combined,
obtained which by vapor-liquid chromato- _. . . .
graphics is fractionated. Repeated 100-I.ambda- 40 ΰ e 1 s ρ 1 e 1 4
Injections onto a 25.4 cm long column with a preparation of methyl propenyl disulfide
0.64 cm in diameter, filled with Carbowax 20 Μ® ^κ

on Chromosorb WA / W® with a temperature-Pro- I _n a 250 ml round-bottomed flask equipped with a stirrer

programming from 75 to 225 ° C at 2 ° / min. results in a cooler, a nitrogen inlet pipe, a

Separation of the isomers with a yield of 45 calcium chloride drying tube and a dropping funnel

a total of 0.043 g of the cis and trans-methyl-propenyldi- is provided, 20 ml of tetrahydrofuran and 1.4 g

sulfides. The structure is given by analysis using magnesium chips. To start the

Vapor-liquid chromatography and mass reaction produce an iodine crystal and a few drops

spectrography in combination with NMR and IR methyl iodide with about 0.5 ml of 1-ßrom-1-propene added

spectro-copic values confirmed. 50 places. The start of the reaction is shown by

. . ,, the disappearance of the iodine color and due to the

^{B e} ' ^sp ' ^e ' ^ί formation "in a light brown color. The rest

Preparation of n-propyl-propcnyldisulfid 1-bromo-1-propene is added in 20 ml of tetrahydrofuran

a) Production of n-Pfopyl-disulfur-chloride at such a rate that the temperature

Starting materials · ^{55 of} the reaction mixture kept between 40 and 45 ° C

8.0 g (0.044 mol) di-propyl trisulfide (distilled); * ^ird · ^Di "°" * ™ ί " ^βη 8 * ^dc * added 1-Bfom-

5.9 g (0.044 mol) sulfuryl chloride (distilled). 1-propene is 7.1 g. The addition time is for an hour.

The reaction mixture is then

Dic procedure of Example 2 Lichem Verwen- under stirring is heated for 1 hour at 70 to 8O ⁰ C,

Use of the above starting materials is repeated. 60 The reaction mixture is then left with stirring

The first fraction will cool down to 33 ° C / 12mm Hg to 40 ° C. Then the propenyl-ma

samniclt. The n-propyl-disehwcfclchlorid becomes a solution drop by drop with a magnesium bromide solution

34 to 3d C 12 π · ηι Hg collected. For each of the two methyl disulfur chloride (8.5 g) in tetrahydro-

Spielc 2 to 4 can use the sulfuryl chloride to obtain the furan, which in a dry ice-isopropanol bath

corresponding Disclmefellnilogcnids is cooled by bromine 65-70 to 75 ^r C, given. The encore will

or chlorine crsci / t be. Similarly, an aborted if the reaction mixture has a dtmkcU

Place animal DimelhyN. Diiilhyl *, or Uipropyl-trisuHidc braimu Iflrbunp assumes. Isopentane (100 ml) will

the di-n-btilyl- or l) i-n-pentyliristillidc soaped / ugcfl'igl and the resulting mixture in a 100 ml

1

Given a separating funnel containing water. The water layer is separated and the organic layer is washed with water (4 x 100 ml), _{dried over Na 1} SO ₄ and the solvent is removed. 7.5 g of a dark-colored oil are obtained. High vacuum distillation (0.02 to 0.05 mm Hg) at room temperature gives 3.5 g of a material collected at -80 "C. A 75 lambda sample (0.0839 g) is subjected to vapor-liquid chromatography and yields 0.025 g of a mixture of the ice uitid trans-methyl-propenyl disulfide. The structures are determined by NMr, IR and mass spectra.

If this procedure is repeated using an equivalent amount of 1-chloro-1-propene in place of the 1-bromo-1-propene, one comes to similar results. Repeating the above procedure using 12.0 g of ethyl disulphur chloride gives 4.2 g after high vacuum distillation. On vapor-liquid chromatography of 0.75 lambda (0.077 g) of the mixture 0.032 g of the cis and trans-ethyl propenyl disulfide are obtained. The structures are represented by NMr, [R and mass spectra determined.

Repeating the above procedure using 13.6 g of the n-propyl disulfur chloride gives 6.2 g after high vacuum distillation. On vapor-liquid chromatography of 75 lambda (0.077 g) of the mixture, 0.028 g of the Obtained cis and trans propyl propenyl disulfide. the Structure of these compounds is determined by NMr, IR and mass spectra.

Example 5 Manufacture of the trisulphides

a) methyl trisulfur chloride

Starting materials:

3.5 g (0.044 mol) of HSSCH _a (methyl hydrodisulfide); 4.8 g (0.044 mol)

CH ₃ -C

S-Cl (acetyl chlorosulfide)

A a 10-mI-KoIben enclosing quartz equipment is heated for 1 hour at 105 ⁰ C in vacuo. After cooling, the ground joints are sealed with 85% phosphoric acid and the entire system is flushed with dry hydrogen chloride gas.

The methyl hydrodisulfid is then placed in the 10 ml flask and - cooled to -20 ⁰ C, followed by added with stirring, the Acetyl-chloro sulfide, then, the mixture to 0 ⁰ C allowed to warm and is applied to the reaction mixture, a slight vacuum. The reaction mixture is then distilled and that

CH ₃ -C

-SS-CH ₃

(Acetyl methyl trisulfide) collected in vacuo. The Acetyl methyl trisulfide is then placed in a 10 ml quartz flask and cooled to -35 ° C. Sulfuryl chloride (0.044 mol) is added to this, the reaction mixture being kept at -35 ° C. during the addition period (30 minutes).

Οίβ

Immediately after the addition, the reaction mixture is allowed to warm to room temperature and the SO ₂ and the acetyl chloride are removed. The remaining material in the flask, methyl trisulfur chloride (CH ₃ SSSCl), is used in step b).

If the above procedure is repeated using equivalent amounts of other alkyl hydrodisulfides in place of the methylhydrodisulfide the corresponding alkyl trisulfur chlorides are obtained.

b) methyl propenyl trisulfide

In a 250 ml round bottom flask equipped with a stirrer, a condenser, a nitrogen inlet tube, a calcium chloride drying tube and a dropping funnel is provided, the following components are given:

20 ml tetrahydrofuran, 1.4 g of magnesium shavings.

To start the reaction, an JodkrisVill and a few drops of methyl iodide with about 0.5 ml of 1-bromo-1-propene was added. The jumping of the Reaction is shown by the disappearance of the iodine

* 5 color and by the formation of a light brown discoloration. The remaining 1-bromo-1-propene is in 20 ml Tetrahydrofuran is added at such a rate that the temperature of the reaction mixture between 40 and 45 "C is maintained. The Ge the total amount of 1-bromo-1-propene is 7.1 g. The addition time is ¹ _{l 1} hour. The reaction mixture is then heated for 1 hour at 70 to 8O ⁰ C with continuous stirring and thereafter the reaction mixture cooled with stirring to ⁰ ° C in an ice bath.

The stirring is then continued in order to keep the reagent in solution. The trisulfur chloride obtained in stage a) then rushes out of the dropping funnel rather quickly added. After adding a larger part, the reaction mixture becomes more liquid and takes a dark brown color. The reaction mixture is then washed twice with water and filtered through sodium bicarbonate to dry. The mixture will concentrated in vacuo to a dark brown oil. The latter contains methyl cis-propenyl trisulfide and Me ethyl transpropenyl trisulfide. The two substances can separated and isolated according to the vapor-liquid chromatography described in Example 1. The corresponding trisulfides are obtained if, instead of the 1-bromo-1-propene, equivalent amounts other 1-bromo-l-alkenes are used or if Instead of methyl trisulfur chloride, other alkyltrisulfur halides can be used. Thus results the use of propyl trisulfur chloride propyl propenyl trisulfide. 1-bromo-1-methyl-1-propcn gives that corresponding alkyl- (l-methyl-propenyl) -trisulphide etc.

Claims (1)

Claim: Process for the preparation of alkyl-1-alkenyldi- and trisulfides of the general formula R ₁ R ₂ RS (S) _n C = CR ₃ in which R and R ₃ denote alkyl radicals, R, and R ₂ hydrogen atoms or alkylresie manufacture and 109 685/282 9 10 / ti or 2, characterized in that R ₁ R ₉ that an alkyl sulfur halide of the general ι rwinen formula _{Mc = CR} RS (S) _n X 5 in which M is lithium, -MgBr or -MgCl, at in which X denotes a halogen atom, reacts with a temperature below room temperature with alkene of the general formula.