PL230831B1 - Dithiogermanates and new selective method for obtaining dithiogermanates - Google Patents

Description

Description of the invention

The subject of the invention is new dithiogermanans containing two germanium-sulfur bonds (S-Ge-S) and a new, selective method of catalytic synthesis of dithiogermanans containing the S-Ge-S moiety.

Organo-germanium compounds containing in their structure a direct connection of germanium and sulfur atoms are, among others used in catalysis, including the synthesis of bimetallic clusters, and as catalysts.

Several methods of obtaining dithiogermanans containing direct german-sulfur bond are known.

Mehrotra (RC Mehrotra, VD Gupta, D. Sukhani, Journal of Organometallic Chemistry 1967, 9, 2, 263-269) disclosed a method involving the reaction between dibutyl dichlorogermanan and thiols (e.g. ethanethiol, propanethiol, butanethiol, tert-butanethiol, benzenethiol) , benzylthiol) in the presence of triethylamine as a proton acceptor. Dibutyldithiogermanates were obtained as reaction products. The reaction is fairly quick with good yield. A significant disadvantage of the described method is the formation of HCl molecules in stoichiometric amounts, which complicates the isolation process or may interfere with further potential one-pot synthesis carried out without the isolation step.

Kobayashi (S. Kobayashi, S. Iwata, M. Abe, S. Shoda, Journal of the American Chemical Society 1995, 117, 8, 2187-2200) disclosed a method involving the reaction between diamidogermylene and benzyldisulfide. The reaction product is diamidobis (benzylthio) germanate obtained in an average yield (58%). The reaction produces a by-product that is difficult to separate from the dithiogermanan. The reaction is carried out at -78 ° C.

Comasseto (J.V. Comasseto, A.S. Guarezemini, Science of Synthesis 2008, 39, 421) described a process involving the reaction between lithium tetrakis (methylthio) aluminate and dimethyl dibromogermanan. The product obtained was dimethyl bis (methylthio) germanate. The reaction proceeds with good yield. Unfortunately, the use of lithium tetrakis (methylthio) aluminate requires the reaction to be carried out at -45 ° C.

The known methods are usually characterized by average or good yields. Some reactions are accompanied by the formation of by-products that are difficult to separate from the main product. Some of the methods require the use of reduced temperature, which requires the use of specialized equipment.

The aim of the invention was to obtain new dithiogermanans containing the S-Ge-S moiety and to develop a new efficient method for the synthesis of dithiogermanans containing the S-Ge-S moiety.

The subject of the invention is new dithiogermanans containing the S-Ge-S group of the general formula 1,

RS — Ge — SR IR ₂ (I) in which:

- R are the same and represent C 1-8 alkyl, cyclohexyl or phenyl groups substituted with a halogen atom;

- Ri, R2 are the same or different and represent: C 1-8 simple alkyl groups.

In a second aspect, the invention relates to a method of synthesizing dithiogermanans containing the S-Ge-S moiety of the general formula 1,

RS — Ge — SR

AND

R ₂ (I) where:

- R represents C1-8 alkyl, cyclohexyl, benzyl, phenyl or phenyl groups substituted with a halogen atom or a C1-3 alkyl group;

- R1, R2 are the same or different and represent: straight C1-8 alkyl groups;

involving a reaction between a thiol of general formula 2,

R-SH (2)

PL 230 831 Β1 in which

R represents C1-e alkyl, cyclohexyl, benzyl, phenyl or phenyl groups substituted with a halogen atom or a C1-3 alkyl group;

and an unsaturated germanium compound of general formula 3

wherein:

- R1 and R2 are as defined above;

in the presence of metal triflates [X (OTf) 3] (formula 4), 'F ύ'

F -------- S --- OX ^J * ~ II

F ⁰ 1 ^{L J3} (4) as a reaction catalyst, wherein X is a scandium, indium, ytterbium or bismuth cation.

The catalyst is used in an amount not less than 0.01 mole of catalyst per mole of germanate. Preferably in an amount of 0.01 to 0.10 moles of catalyst per mole of germanate. It is most preferred to use the catalyst in an amount of 0.078 to 0.081 moles of catalyst per mole of germanate.

The reaction according to the invention is carried out in a polar aromatic, ether or nitrile solvent. It is preferable to carry out the reaction in solvents selected from the group of: benzene, toluene, fluorobenzene, chlorobenzene and acetonitrile. It is especially preferable to carry out the reaction in acetonitrile.

The reaction takes place in any molar ratio of germanate to thiol, but due to the unpleasant odor of the thiols, it is preferable to carry out the reaction with a germanate-thiol molar ratio of 1-2.4.

The reaction according to the invention takes place independently of the temperature of the reaction mixture, however, it is preferable to operate at room temperature.

The method of synthesizing dithiogermanates according to the invention consists in introducing the unsaturated germanium compound of formula III, a solvent, thiol and a catalyst into the reactor, it is preferred to add the catalyst last. Taking into account the properties of the organo germanium compounds used, it is advantageous to carry out the reaction in a dehydrated solvent under an inert gas atmosphere, e.g. argon. The reaction mixture may be stirred to accelerate the reaction. The duration of the synthesis is from 1 to 3 hours.

The crude product is purified by known methods from the catalyst, by-products and residual unreacted reagents. The preferred method of purifying the crude product is by extracting it from the reaction mixture with hexane.

The use of metal triflates as reaction catalysts in the process according to the invention enables the desired products to be synthesized in high yield. In practice, small amounts of catalyst (8 mol%) are used. The most advantageous is the use of scandium triflate, because the reaction in its presence proceeds with the highest efficiency and the shortest time. Additional advantages of the process according to the invention are the mild conditions (25 ° C) and the short reaction time (1-3 hours).

The process according to the invention, unlike those known so far, is characterized by a relatively short process time (1-3 hours), mild conditions (25 ° C) and allows, by selecting appropriate germanates and thiols, to synthesize any designed germanium-sulfur coupling products of general formula I, with high yields up to 93% of theory. The yields of the thiogermanans obtained according to the invention are about 5% higher than those obtained by Merhotra, and the only by-product of the reaction carried out according to the invention is 2-methylpropene, which does not interfere with further potential synthesis using the "one-pot" technique.

The novel compounds disclosed in the present invention can be used as substrates in substitution reactions involving aromatic iodides and bromides, which allow the synthesis of asymmetric sulfides. Sulfides are used, among others in fungicides and insecticides.

PL 230 831 Β1

The following examples illustrate the invention. The structure of the obtained sulfur-containing organo-germanium compound was confirmed by the techniques of gas chromatography combined with mass spectrometer (GC-MS, Varian Saturn 2100T spectrometer) and nuclear magnetic resonance spectroscopy (NMR, Bruker Avance III HD NanoBay).

Example I.

In a 10 ml single-neck round flask with a stir bar there were placed: 2 ml of acetonitrile, 0.020 g (8.26 × 10 ⁵ mol) of bis (2-methylallyl) diethyl manane, and 0.016 g (1 × 10 ⁴ mol) of 3-methylbutanethiol . To the thus prepared solution was added 0.0033 g (6.6 × 10 ⁶ mol) of scandium trifluoromethanesulfonate. The system was stirred for 1 hour at the temperature of 25 ° C. After completion of the reaction, the solvent and thiol residues were evaporated, followed by extraction of the crude product with hexane. The crude product along with hexane was transferred to a new flask and then the solvent was evaporated under reduced pressure to give the main reaction product. 0.025 g of pure diethyl bis [(3-methylbutyl) thio] germanate was obtained, 90% of theory. The product structure was confirmed by mass spectrometry and NMR spectroscopy.

¹ H NMR (400 MHz, C ₆ D ₆ ): δ (ppm) = 0.83 (m, 12H), 1.08 (m, 6H), 1.17 (m, 4H), 1.56 (m , 4H), 1.70 (m, 2H), 2.72 (m, 4H).

¹³ C NMR (101 MHz, C ₆ D ₆ ): δ (ppm) = 8.6; 11.5; 22.0; 25.4; 27.2; 42.2.

MS (EI) m / z (int. Rei): 309 (100%, (MC ₂ H ₅ ) ⁺ ), 236 (30), 205 (10), 167 (3), 149 (3), 135 ( 3), 107 (5), 71 (5).

Example II

In a 10 ml single neck round flask equipped with a stir bar were placed: 2 ml of acetonitrile, 0.020 g (8.26 × 10 ⁵ mol) bis (2-methylallyl) diethyl manane, and 0.018 g (1.98 × 10 ' ⁴ mol) tert-butanethiol. To the thus prepared solution was added 0.0033 g (6.6 × 10 ⁶ mol) of scandium trifluoromethanesulfonate. The system was stirred for 1 hour at the temperature of 25 ° C. After completion of the reaction, the solvent and thiol residues were evaporated, followed by extraction of the crude product with hexane. The crude product along with hexane was transferred to a new flask and then the solvent was evaporated under reduced pressure to give the main reaction product. 0.023 g of pure diethyl bis [(tert-butyl) thio] germanate was obtained, 88% of theory. The product structure was confirmed by mass spectrometry and NMR spectroscopy.

¹ H NMR (400 MHz, C ₆ D ₆ ): δ (ppm) = 1.13 (m, 4H), 1.19 (m, 6H), 1.47 (s, 18H).

¹³ C NMR (101 MHz, C ₆ D ₆ ): δ (ppm) = 8.7; 14.6; 35.3; 45.5.

MS (EI) m / z (int. Rei): 295 (2%, (M-CH ₃ ) ⁺ ), 219 (5), 197 (15), 169 (100), 135 (7), 107 ( 5), 57 (20).

Example III

In a 10 ml single-neck round flask, equipped with a stir bar, were placed: 2 ml of acetonitrile, 0.020 g (8.26 × 10 ⁵ mol) bis (2-methylallyl) diethyl manane, and 0.018 g (1.98 × 10 ⁴ mol) n -butanethiol. To the thus prepared solution was added 0.0033 g (6.6 × 10 ⁵ mol) of scandium trifluoromethanesulfonate. The system was stirred for 1 hour at the temperature of 25 ° C. After completion of the reaction, the solvent and thiol residues were evaporated, followed by extraction of the crude product with hexane. The crude product along with hexane was transferred to a new flask and then the solvent was evaporated under reduced pressure to give the main reaction product. The obtained 0.023 g of pure diethyl bis [(n-butyl) thio] germanate was 93% of theory. The product structure was confirmed by mass spectrometry and NMR spectroscopy.

¹ H NMR (400 MHz, C ₆ D ₆ ): δ (ppm) = 0.91 (t, J = 7.4 Hz, 6H), 1.16 (m, 4H), 1.22 (m, 6H ), 1.44 (m, 4H) 1.67 (m, 4H), 2.75 (m, 4H).

¹³ C NMR (101 MHz, C ₆ D ₆ ): δ (ppm) = 8.7; 11.6; 13.5; 21.9; 27.1; 35.3.

MS (EI) m / z (int. Rei): 281 (100%, (MC ₂ H ₅ ) ⁺ ), 221 (30), 167 (2), 135 (5), 105 (5), 57 ( 5).

Example IV

In a 10 ml single-neck round flask, equipped with a stir bar, there were placed: 2 ml of acetonitrile, 0.020 g (8.26 × 10 ⁵ mol) of bis (2-methylallyl) diethyl manane, and 0.023 g (1.98 × 10 ⁴ mol) of cyclohexanethiol . To the thus prepared solution was added 0.0033 g (6.6 × 10 ⁶ mol) of scandium trifluoromethanesulfonate. The system was stirred for 1 hour at the temperature of 25 ° C. After completion of the reaction, the solvent and thiol residues were evaporated, followed by extraction of the crude product with hexane. The crude product along with hexane was transferred to a new flask and then the solvent was evaporated under reduced pressure to give the main reaction product. The obtained 0.03 g of pure diethyl bis [(cyclohexyl) thio] germanate was 89% of theory. The product structure was confirmed by mass spectrometry and NMR spectroscopy.

PL 230 831 Β1 ¹ H NMR (400 MHz, C ₆ D ₆ ): δ (ppm) = 1.11 (m, 6H), 1.16 (m, 4H), 1.22 (m, 6H), 1 , 38 (m, 2H), 1.57 (m, 4H), 1.67 (m, 4H), 2.08 (m, 4H), 3.11 (m, 2H).

¹³ C NMR (101 MHz, C ₆ D ₆ ): δ (ppm) = 8.7; 12.3; 25.5; 26.2; 37.8; 41.4.

MS (EI) m / z (int.rei): 333 (100%, (MC ₂ H ₅ ) ⁺ ), 251 (40), 167 (15), 135 (5), 107 (5), 83 ( 5), 55 (35).

Example V

In a single-necked 10 ml round-bottom flask equipped with a stir bar were placed: 2 ml of acetonitrile, 0.020 g (8.26 × 10 ⁵ mol) bis (2-methylallyl) diethyl manane, and 0.025 g (1.98 × 10 ⁴ mol) p -fluorobenzenethiol. To the thus prepared solution was added 0.0033 g (6.6 × 10 ⁶ mol) of scandium trifluoromethanesulfonate. The system was stirred for 1 hour at the temperature of 25 ° C. After completion of the reaction, the solvent and thiol residues were evaporated, followed by extraction of the crude product with hexane. The crude product along with hexane was transferred to a new flask and then the solvent was evaporated under reduced pressure to give the main reaction product. The obtained 0.032 g of pure diethyl bis [(p-fluorophenyl) thio] germanate was 85% of theory. The product structure was confirmed by mass spectrometry and NMR spectroscopy.

¹ H NMR (400 MHz, C ₆ D ₆ ): δ (ppm) = 0.88 (m, 10H), 6.53 (m, 1H), 6.62 (m, 3H), 7.08 (m , 1H). 7.33 (m, 3H).

¹³ C NMR (101 MHz, C ₆ D ₆ ): δ (ppm) = 8.2; 11.4; 115.8 (d, J = 21.8 Hz), 136.8 (d, J = 8.0 Hz), 161.3 (d, J = 12.3 Hz), 163.7 (d, J = 13, 2 Hz).

MS (EI) m / z (int. Rei): 357 (10%, (MC ₂ H ₅ ) ⁺ ), 259 (100), 229 (15), 201 (5), 127 (10), 83 ( 7).

Claims (6)

Patent claims 1. Dithiogermanans of general formula 1, RS — Ge — SR I R ₂ (I) where: - R are the same and represent C1-8 alkyl, cyclohexyl or phenyl groups substituted with a halogen atom; - R 1, R ₂ are the same or different and represent: simple C 1-8 alkyl groups; 2. Synthesis of dithiogermanans containing the S-Ge-S group of the general formula 1, RS — Ge — SR I «2 (|) in which: - R represents C1-e alkyl, cyclohexyl, benzyl, phenyl or phenyl groups substituted with a halogen atom or a C1-3 alkyl group; - R 1, R ₂ are the same or different and represent: simple C 1-8 alkyl groups; characterized in that it consists in the reaction between a thiol of general formula 2, R-SH (2) where: R represents C1-8 alkyl, cyclohexyl, benzyl, phenyl or phenyl groups substituted with a halogen atom or a C1-3 alkyl group; a unsaturated germanium compound of general formula 3, (3) PL 230 831 Β1 wherein Ri and R2 are as defined above; in the presence of metal triflates [X (OTf) 3 of general formula 4, (4) wherein X is a scandium, indium, ytterbium or bismuth cation acting as a catalyst, the reaction being carried out in a polar aromatic, ether or nitrile solvent. 3. The method according to p. The process of claim 2, wherein the catalyst is scandium triflate. 4. The method according to p. 2. The method of claim 2 or 3, characterized in that the catalyst is used in an amount of not less than 0.01 mole of catalyst per mole of germanate. 5. The method according to p. 4. The process of claim 4, wherein the catalyst is used in an amount of 0.01 to 0.1 mole of catalyst per mole of germanate. 6. The method according to p. 5. A process as claimed in Claim 5, characterized in that the catalyst is used in an amount of 0.078 to 0.081 mole of catalyst per mole of germanate.