DE1443873B - Process for the preparation of amidocarbonyl isothiocyanates - Google Patents

Description

The invention relates to a chemically peculiar process for the preparation of new amidocarbonyl isothiocyanates.

It has been found that amidocarbonyl isothiocyanates are obtained when using isocyanates of the general formula

R- (NCO) _n -

in which R stands for an optionally substituted hydrocarbon radical with up to 25 carbon atoms stands, which by an ether, sulfide, sulfone,

- C-

- CH ₂ - or - CH bridge

Method for the production of thiocarbamic acid chloride. So it would have to be expected that at the reaction according to the invention both isocyanates and the hydrogen rhodanide alone with Hydrogen chloride would react to form N-substituted carbamic acid chlorides and Thiocarbamic acid chlorides. Surprisingly, these reactions do not appear, and the N-substituted amidocarbonyl isothiocyanates are obtained in very good yields.

If the reaction according to the invention is based on phenyl isocyanate and hydrogen rhodanide, then the reaction according to the invention can be represented by the following equation:

N = CO + H -NCS

NH-CO-NCS

The isocyanates used as starting materials are clear from the above general formula characterized. R therein preferably represents an optionally substituted hydrocarbon radical with up to 20 carbon atoms. You can use an ether, sulfide, sulfone,

C-O

can be interrupted and η stands for 1 or 2, with hydrogen rhodanide in the presence of an inert organic solvent at -80 to +50 ⁰ C to give compounds of the general formula

R- (NH-CO-NCS) _n

in which R and η have the meaning given.

In place of the hydrogen rhodanic acid, a salt of the hydrohalic acid and hydrogen halide can also be used use, whereby the free hydrogen rhodanide develops in the reaction mixture.

The course of the implementation according to the invention is surprising. Namely, it is known that isocyanates react smoothly with hydrogen halides to form carbamic acid halides. It is also known that Hydrogen halides react with free hydrogen rhodanide. So z. B. the action of hydrogen chloride a preparative one on hydrogen rhodanide

- CH, - or - CH bridge

be interrupted. The hydrocarbon radicals are preferably substituted by halogen, especially Chlorine and bromine, nitro, cyano, alkoxy, alkoxycarbonyl, alkylcarbonyl, alkylcarbonyloxy, alkenylcarbonyloxy, Alkylthio and alkylsulfonyl groups, the alkyl radicals preferably having 1 to 6 carbon atoms contain. They can also be substituted by haloalkyl having 1 to 4 carbon atoms, like trifluoromethyl.

Examples of the monoisocyanates and diisocyanates to be used are the following compounds which are already known (see e.g. Liebig's Annalen der Chemie, 562, p. 75 [1949]):

Methyl isocyanate,

Ethyl isocyanate,

Allyl isocyanate,

n-butyl isocyanate,
Dodecyl isocyanate,

Cyclohexyl isocyanate,

4- (cyclohexylmethyl) cyclohexyl isocyanate,

Diethyl methyl isocyanate,

1 -chloroethyl-2-isocyanate,
l-chlorhexyl-o-isocyanate,

l-cyanoethyl-2-isocyanate,

Isocyanate acetic acid ethyl ester,

2-isocyanatoethyl methacrylate,

Ethoxymethyl isocyanate,
3-butoxypropyl isocyanate.

2-ethylthioethyl isocyanate,

Phenyl isocyanate,

p-tolyl isocyanate,

Benzyl isocyanate,
ß-phenylethyl isocyanate,
4-cyclohexylphenyl isocyanate,
3-chlorophenyl isocyanate,
3,4,6-trichlorophenyl isocyanate,
Pentachlorophenyl isocyanate,
3-nitrophenyl isocyanate,
3-cyanophenyl isocyanate,
2-trifluoromethylphenyl isocyanate,
4-methoxyphenyl isocyanate,
4-carbonyl methoxyphenyl isocyanate,
2,5-dimethoxyphenyl isocyanate,
4-ethoxycarbonylphenyl isocyanate,
4,4'-dichlorodiphenyl ether-2-isocyanate,
1-naphthyl isocyanate,
l-chloro ^ -naphthyl isocyanate,
Phenanthryl-3-isocyanate,
Ethane diisocyanate,
Hexane-1,6-diisocyanate,
2,2'-diisocyanatodiethyl sulfide,
S-methoxyhexane-ljo-diisocyanate,
Dodecane-1,12-diisocyanate,
p-xylylene diisocyanate,
Cyclohexane-l ^ -diisocyanate,
Dicyclohexylmethane-4,4'-diisocyanate
4-isocyanato-phenylmethyl isocyanate,
4- (p-isocyanato) -cyclohexylphenyl isocyanate,
1,3-phenylene diisocyanate,
Toluene-2,4-diisocyanate,
l-chlorobenzene-2,4-diisocyanate,
l-nitrobenzene ^ S-diisocyanate,
1, S-dichlorobenzene ^^ - diisocyanate,
!, S-dimethoxybenzene ^ o-diisocyanate,
Diphenyl ether 2,4-diisocyanate,
Naphthalene-1,5-diisocyanate,
Diphenyl-2,4'-diisocyanate,
Diphenylmethane-4,4'-diisocyanate,
3-nitro-triphenylmethane-4,4-diisocyanate,
Diphenyl sulfide ^^ '- diisocyanate,
Diphenylsulfone-4,4'-diisocyanate,
Benzophenone-3,3 '-diisocyanate,
4-methyl-3-isocyanatobenzenesulfonyl-4'-isocyanatophenol ester.

Pure, dry hydrogen rhodanide is used as the second component. Since the manufacture is relatively difficult, it is preferable to use a salt of hydrofluoric acid, such as the alkali salts, Alkaline earth salts, heavy metal salts, such as the lead salt, the ammonium salt or a trialkylammonium salt, and a hydrogen halide, preferably hydrogen chloride.

As inert organic solvents, all organic solvents come into question, which with the Reaction components do not react. These include preferably aliphatic and aromatic Hydrocarbons and halogenated hydrocarbons and ethers, e.g. B. diethyl ether and ketones, e.g. B. Acetone.

The reaction temperatures can be varied over a wide range. Preferably 80 and + 50 ° C, between -20 and + 2O ⁰ C. - in general carried out between

When carrying out the process according to the invention, 0.8 to 1.5 mol of hydrogen rhodanide are used for 1 mol of isocyanate group. If you work with salts of a hydrohalic acid and a hydrohalic acid, the same molar ratios apply. The individual reaction partners are added to the solution. The reaction mixture is kept in the specified temperature range and then worked up in the usual way.
The salts of the hydrohalic acid used which are formed during the reaction can be separated off from the reaction solution by simple filtration. After the solvent has been separated off, the filtrate gives the process products, some of which are oily compounds, some of which crystallize well.

The N-substituted amidocarbonyl isothiocyanates obtainable by the process according to the invention represent valuable new compounds. They are particularly characterized by a strong fungitoxic Effect. Since their warm-blooded toxicity is very low, they can be used to combat undesirable Find mushroom growth use. Furthermore, their compatibility with higher plants allows them to be used as a pesticide against fungal plant diseases.

example 1

In a solution of 119 parts of phenyl isocyanate in 100 parts of acetone, 36.5 parts of hydrogen chloride are passed in at 5 to 1O ⁰ C. A solution of 76 parts of ammonium thiocyanate in 250 parts of acetone is added dropwise to the clear reaction solution at 5 to 10 ° C. with cooling. An exothermic reaction takes place and ammonium chloride precipitates. The resulting suspension is stirred for 1 hour at room temperature. After the ammonium chloride has been separated off by filtration, a clear yellow solution is obtained which is evaporated in vacuo. 130 parts of N-phenylamidocarbonyl mustard oil remain in the residue in the form of yellow crystals. After recrystallization from benzene, the substance has a melting point of 108 ° C. Yield: 73% of theory.
The constitution of the compound is reliably demonstrated with the help of the IR spectrum. The spectrum has the characteristic bands for an acyl mustard oil at 1970 cm " ¹ , furthermore an NH band at 3280 to 3320 cm" ¹ , a carbonyl band at 1670 to 1690 cm " ¹ and an NH-CO band at 1530 cm" ¹ .

Example 2

a) 153.5 parts of p-chlorophenyl isocyanate are with 36.5 parts of hydrogen chloride and 76 parts of ammonium thiocyanate according to that given in Example 1 Working method implemented. 180 parts of crude N- (4-chlorophenyl) amidocarbonyl mustard oil are obtained as the reaction product in the form of light yellow crystals, which after recrystallization from benzene at 127 ° C melt.

b) 36.5 parts of hydrogen chloride are passed at -5 ° C. into a solution of 76 parts of ammonium thiocyanate in 250 parts of acetone. To the resulting suspension is added dropwise 153.5 parts of p-chlorophenyl isocyanate at -5 ⁰ C. After the exothermic reaction has subsided, the suspension is ^{stirred at 10 to 20 °} C. for 2 hours. The ammonium chloride formed is filtered off and the resulting clear solution is evaporated in vacuo. 175 parts of N- (4-chlorophenyl) amidocarbonyl mustard oil remain in the residue in the form of pale yellow crystals (mp 126 ° to 127 ° C. from benzene).

Example 3

160 parts of p-phenylene diisocyanate are in 400 parts Dissolved acetone. 73 parts of hydrogen chloride are passed into this solution at 10 to 20 ° C. and added dropwise then a solution of 152 parts of ammonium thiocyanate in 400 parts of acetone. The emerging Crystal slurry is stirred for 1 hour at room temperature and then suction filtered. The filter cake is boiled several times with dioxane. The combined filtrates are evaporated in vacuo, 240 parts of a yellow wax remaining in the residue. The residue becomes with the trituration a little acetone crystalline. After the acetone mother liquor has been separated off, 154 parts of 1,4-bis (isothiocyanatocarbonylamido ^ benzene are obtained in the form of yellow crystals which melt at 138 ° C (decomp.). The The IR spectrum of the compound shows the characteristic bands mentioned in Example 1.

Example 4

A solution of 35.5 parts of ethyl isocyanate in 100 parts of acetone is initially passed at -5 ° C 18.5 parts of hydrogen chloride and then, with cooling, a solution of 38 parts of ammonium thiocyanate in 150 parts of acetone. After the reaction, the mixture is stirred at 20 ° C. for 1 hour. Then it will be the precipitated ammonium chloride is filtered off and the clear yellow solution is evaporated in vacuo. in the 63 parts of N-ethylamidocarbonyl mustard oil remain in the form of a yellow oil. The IR spectrum shows the characteristics given in Example 1 Gangs. For a more detailed characterization, the compound is converted into the Thiourethane of the formula

C ₂ H ₅ - NH - CO - NH - CS - OCH ₃
transferred, which melts at 100 ° C.

Example 5

Obtained from 41.5 parts of allyl isocyanate, 18.5 parts of hydrogen chloride and 40.5 parts of sodium thiocyanate 72 parts of N-allylamidocarbonyl mustard oil in the form of the procedure given in Example 4 of a yellow ule. The reaction product with methanol of the formula is used for characterization

CH ₂ = CHCH ₂ -NH-CO-NH-CS-OCh ₃ . (M.p. 78 ° C).

Example 6

From 42.5 parts of n-propyl isocyanate, 18.5 parts Hydrogen chloride and 38 parts of ammonium thiocyanate are obtained analogously to Example 4, 72 parts of N-n-propylamidocarbonyl mustard oil in the form of an oil. The thiourethane obtainable therefrom when exposed to methanol the formula

Example 7

163 parts of 4-ethoxyphenyl isocyanate are mixed with 36.5 parts of hydrogen chloride and 76 parts of ammonium thiocyanate implemented analogously to Example 4. When the reaction solution freed from ammonium chloride is evaporated, 210 parts of the crude are obtained N- (4-Äthoxyphenyl) -aipjidocarbonylsenföles as waxy Dimensions. When recrystallizing from benzene, colorless crystals with a melting point are obtained 143 ° C. Yield: 94% of theory.

Examples

188 parts of 3,4-dichlorophenyl isocyanate are with 36.5 parts of hydrogen chloride and 76 parts of ammonium thiocyanate were reacted analogously to Example 4. As a reaction product 220 parts of N-3,4-dichlorophenylamidocarbonyl mustard oil are obtained in the form of a yellow Wax whose IR spectrum has the characteristic bands mentioned in Example 1. To the closer characterization is the crude product with isopropanol to thiourethane of the formula

NH-CO-NH-CS-O-CH (CH ₃ ) ₂

implemented. F. 166 to 167 ° C. '

Example 9

Obtained from 67 parts of benzyl isocyanate, 18.5 parts of hydrogen chloride and 38 parts of ammonium thiocyanate according to the procedure given in Example 4, 180 parts of N-benzylamidocarbonyl mustard oil in Form of a yellow wax that cannot be purified by crystallization. By implementing with Methanol turns it into the crystalline thiourethane of the formula

CH, - NH - CO - NH - CS - OCH,

transferred (m.p. 95 to 96 ° C).

Example 10

From 153.5 parts of 3-chlorophenyl isocyanate, 36.5 parts Hydrogen chloride and 76 parts of ammonium thiocyanate are obtained analogously to Example 4, 210 parts N-3-chlorophenylamidocarbonyl mustard oil in the form of a yellow wax, from which a crystalline thiourethane of the following formula is obtained with isopropanol will:

NH - CO - NH - CS - O - CH (CH ₃ ) ₂

nC ₃ H ₇ - NH - CO - NH - CS - OCH ₃
melts at 9 Γ C.

6o

Claims (1)

Claim: Process for the preparation of amidocarbonyl isothiocyanates, characterized in that that one isocyanates of the general formula R- (NCO) _n wherein R is an optionally substituted hydrocarbon radical having up to 25 carbon atoms stands, which by an ether, sulfide, sulfone, - C- - CH ₂ or - CH bridge can be interrupted and η stands for 1 or 2, with hydrogen peroxide in the presence of an inert organic solvent at -80 to +50 ⁰ C to give compounds of the general formula R - (NH - CO - NCS) _n in which R and η have the meaning given.