DE1249873B - Process for the preparation of 1,3,4 thiadiazoles - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

C07d

Int. α .:

German KL: 12p-9

Number: 1249 873

File number: B66038IVd / 12p

Filing date: February 21, 1962

Date of issue: September 14, 1967

It is known that 1,3,4-thiadiazoles are obtained if a diacylhydrazine is used with phosphorus pentasulfide heated (R. S t o 11 e, reports of the German Chemical Society, Vol. 32 [1899], p. 797/798). The thiadiazoles obtained are not pure and have to be purified before further use. The process can also be used with starting materials with substituents, such as amino or hydroxyl groups, do not use, as these are changed by the action of phosphorus pentasulphide.

1,3,4-thiadiazoles can be also prepared by reacting Thiocarbonsäurehydraziden with Imidoätherhydrochloriden at 50 to 100 ⁰ C (commemorative Carl Wurster, BASF, Ludwigshafen / Rhein, 1960, S. 125). Although the ring closure of thiocarboxylic acid hydrazides with imido ether hydrochlorides takes place without difficulty, the preparation of the thiocarboxylic acid hydrazides used as starting material from hydrazine and thioacylating agents is generally difficult. It is also not possible to allow the thiocarboxylic acid hydrazides to form in the reaction mixture, because it has to be carried out in an aqueous alkaline solution, but the further reaction with the imido ether hydrochloride takes place in an inert organic solvent.

It is also known (Bull. Soc. Chim. France, 1949, pp. 237 to 240) that one in the 2- and 5-position 1,3,4-thiadiazoles substituted by identical radicals from 2 moles of a thiobenzoic acid amide by oxidative Can produce ring closure with N-dichlorocarbamic acid methyl esters. According to this well-known Processes cannot be prepared asymmetrically substituted 1,3,4-thiadiazoles. To This process can also not produce 2,5-disubstituted 1,3,4-thiadiazoles, in which the substituents are anthraquinone or substitution products thereof.

Finally, there is a process for the preparation of 2,5-diphenyl-1,3,4-thiadiazole and its in the phenyl radical substituted derivatives known in which one dibenzhydrazide chloride or its in the phenyl radical substituted derivatives in aqueous-alcoholic suspension with a sulfide or hydrogen sulfide of the alkali or Converts alkaline earth metals.

A disadvantage of this process is that the dibenzoylhydrazine or its derivatives substituted in the phenyl nucleus have to be converted into the corresponding dibenzhydrazide chlorides. Di ₇ acylhydrazines with substituents which react with chlorine, such as amino or hydroxyl groups, cannot be used here either. In addition, processes for the preparation of 1,3,4-thiadiazoles

Applicant:

Aniline & Soda Factory in Baden
Aktiengesellschaft, Ludwigshafen / Rhein

Named as inventor:

Dr. Hans Weidinger, Limburgerhof (Palatinate);

Dr. Heinz Eilingsfeld, Ludwigshafen / Rhine

no 2,5-disubstituted 1,3,4-thiadiazoles in this process of the anthraquinone series.

It has been found that 1,3,4-thiadiazoles of the 'formula

N-

Ri

C CR ₂

where Ri is a hydrogen atom, one optionally by nitro, amino, hydroxy, carboxy or nitrile groups substituted alkyl, cycloalkyl, Aralkyl, aryl or a heterocyclic radical or the radical

C - A -

where A is an alkylene or phenylene radical and X is an aromatic radical, and R2 is one by nitro, amino, hydroxy, carboxy or nitrile groups substituted alkyl, cycloalkyl, Aralkyl, aryl radical or the radical '

N-A-C

Il c-x

where A and X have the aforementioned meaning, without these disadvantages, if one mono-

709 647/541

thiodiacylhydrazines of the formula

NH -NH

Ri-C

sc

CR ₂

wherein Ri and R _{2 have} the aforementioned meaning and also Ri

and R ₂

NH-
-AC

NH- A -C

NH
CX

NH
CX

OS

wherein A and X have the abovementioned meaning, may be, or the reaction mixture of a corresponding carboxylic acid hydrazide and a corresponding thioacylating in a solvent and in the presence of an acid at 20 to 150 ° C, preferably at 50, heated to 100 ⁰ C. As starting materials, for. be used as: Thioformylbenzoylhydrazin, Thioacetylacetylhydrazin, Thioacetylcyclohexyloylhydrazin, Thioacetylphenylacetylhydrazin, thioacetyl-4-methoxybenzoylhydrazin, thioacetyl - [1 - aminoanthrachinonoyl - (2)] - hydrazine, Thioacetylisonicotinylhydrazin, Thiocyclohexyloylacetylhydrazin, Thiocyclohexyloylbenzoylhydrazin, Thiophenylacetylbenzoylhydrazin, Thioisonicotinyl - 4 - chlorobenzoylhydrazine, Thioanthrachinonoyl - ( 2) - benzoylhydrazine, [thio -1 - aminoanthraquinonoyl - (2)] - [1 - aminoanthraquinonoyl - (2)] - hydrazine, thioanthrapyrimidyloyl (2) - [1 -aminoanthraquinonoyl - (2)] - hydrazine, di - ( thioacetyl) - adipic acid, di- [thio-l-aminoanthrachinonoyl- (2)] - terephthalic acid dihydrazide, Thiobenzoylbenzoylhydrazin, thiobenzoyl-4-nitrobeuzoylhydrazin, TMobenzoyl - 4 - methoxybenzoylhydrazin, thiobenzoyl-4 - aminobenzoylhydrazin, thiobenzoyl - 2 - hydroxybenzoylhydrazin, Thiobenzoylisonicotinylhydrazin, Thiobenzoylacetylhydrazin , Thiobenzoylcyanacetylhydrazine, thiobene zoyl- [l-aminoanthraquinonoyl- (2)] - hydrazine, thiobenzoyl - [1,4 - diaminoanthraquinonoyl- (2)] - hydrazine, di- [l-aminoanthraquinonoyl- (2)] - dithioterephthalic acid dihydrazide, 4-chlorothiobenzoylhydrazine, 4 - Chlorothiobenzoyl - 2 - hydroxybenzoyl hydrazine, 4 - chlorothiobenzoyl - [1 - aminoanthraquinonoyl - (2)] - hydrazine, 4 - chlorothiobenzoyl - [1,4 - diaminoanthraquinonoyl - (2)] - hydrazine, 4 - chlorothiobenzoylisonicotinylhydrazine, di- [4-chroquinonoyl ] -adipic acid dihydrazide, di - [4 - chlorothiobenzoyl] -terephthalic acid dihydrazide, 4 - methoxythiobenzoylbenzoylhydrazine, ^ -methoxythiobenzoylacetylhydrazine, 4-methoxythiobenzoyl-2-hydroxybenzoylhydrazine, 2-methoxythiobenzoyl-2-hydroxybenzoylhydrazine, 4-methoxythiobenzoyl-2-hydroxybenzoylhydrazine, 4-methoxylenzoyl-4-amino-benzoythoxy-2-hydroxybenzoylhydrazine, 4-methoxylenzoyl-4-methoxybenzoyl (1-methoxybenzoyl-2-methoxenzo-4-methoxybenyl-4 ] hydrazine, 4-methoxythiobenzoyl [1,4-diaminoanthraquinonoyl - (2)] hydrazine, di - [4 - methoxythiobenzoyl] adipic acid dihydrazide and di- [4 - methoxythiobenzoyl] terephthalic acid dihydrazide.

The monothiodiacylhydrazines mentioned are new compounds. You can z. B. easy to manufacture, by carboxylic acid hydrazides with thioacylating agents, such as dithiocarboxylic acids or their Esters, thiocarboxylic acid esters, N-succinylthiocarboxamides or N-phthalylthiocarboxamides, implements.

The monothiodiacylhydrazine is advantageously used only prepare in the reaction vessel from a carboxylic acid hydrazide and a thioacylating agent.

Suitable solvents are, for. B. concentrated sulfuric acid, glacial acetic acid, low molecular weight aliphatic Alcohols such as methanol and ethanol, cyclic ethers such as dioxane, optionally substituted aromatic Hydrocarbons such as benzene, toluene, chlorobenzene, o-dichlorobenzene and nitrobenzene, as well Dimethylformamide and N-methylpyrrolidone. Will not already be an acid as a solvent is used, it is advantageous to add an acid to the transfer mixture. Suitable acids are, for example, sulfuric acid, hydrochloric acid, formic acid, acetic acid or p-toluenesulfonic acid. Man uses about 0.05 to 1 mole of acid per mole of monothiodiacylhydrazine, but is an excess not harmful.

The process is carried out by adding the monothiodiacylhydrazine and optionally a Introduces acid into the solvent and then heated the mixture to the desired temperature. Ever at the chosen temperature, the reaction takes about 10 minutes to 48 hours completed. The work-up of the reaction mixture can, for. B. from water-miscible solvents be carried out in such a way that the solution is diluted with water and the mixture is optionally made alkaline and the deposited crystals are filtered off. At with Water-immiscible organic solvents, the solvent is removed by distilling off and the residue was washed with 2η sodium hydroxide solution and then with water and dried.

The 1,3,4-thiadiazoles obtainable in good yield and high purity by the process of the invention some are dyes, optical brighteners or plastic stabilizers. You can also used as intermediates for the manufacture of dyes and medicines.

Unless otherwise stated, the parts mentioned in the examples are parts by weight. Room parts relate to parts by weight as liters to kilograms.

example 1

A solution of 10 parts TJuobenzoylberizoylhydrazin and 10 parts of p-Toiuolsulfonsäure in 100 parts of N-methylpyrrolidone is heated for 20 minutes from 70 to 8O ⁰ C. After cooling, the reaction mixture is added water in about 500 parts, filtered and the precipitate with 2 n- Sodium hydroxide solution and then washed with water. 9 parts of 2,5-piphenyl-1,3,4-thiadiazole are obtained as colorless crystals "vöW""Sc ^ mHzfM ^

If the same amount of dimethylformamide is used instead of N-methylpyrrolidone, one obtains 2,5-diphenyl-1,3,4-thiadiazoline with the same yield and purity.

The thiobenzoylbenzoylhydrazine used as starting material can be prepared as follows: A

A mixture of 50 parts of ethyl thiobenzoate, 50 parts of benzoic acid hydrazide, 500 parts by volume of diethyl ether and 300 parts by volume of 1 η sodium hydroxide solution is ^{shaken at 20 °} C. for 10 hours. The ether layer is separated and discarded and the aqueous solution is acidified with acetic acid. It is filtered and the residue is washed with water. This gives 85 parts Thiobenzoylbenzoylhydrazin as colorless crystals of melting point 130 ⁰ C.

B e i s ρ iel 2

A solution of 10 parts in 100 parts of concentrated sulfuric acid Thiobenzoylbenzoylhydrazin {d = 1.84) is stirred for 10 minutes at 20 ⁰ C. It is then poured into about 500 parts of water and filtered off. The filter residue is washed with water and dried. 9 parts of 2,5-diphenyl-1,3,4-thiadiazole are obtained as colorless crystals with a melting point of 140 to 141 ^° C.

B e i s ρ i e 1 3

A solution of 26.7 parts of N-Phthalylthiobenzoesäureamid and · 16 parts of benzoic acid hydrazide in 120 parts of N-methylpyrrolidone is heated for 30 minutes 30 to 40 ⁰ C. Add 15 parts of p-toluenesulfonic acid added and then the mixture was heated 10 minutes 70 ⁰ C. The cooled reaction mixture is added to about 150 parts of water and the mixture is made alkaline by adding sodium hydroxide solution. After filtering, the filter residue is washed with water and dried. 22.5 parts of 2,5-diphenyl-1,3,4-thiadiazole are obtained as colorless crystals with a melting point of 140 ° to 141 ° C.

Example 4

A solution of 26.7 parts of N-phthalylthiobenzoic acid amide and 22 parts of p-nitrobenzoic acid hydrazide in 150 parts of N-methylpyrrolidone is heated to 40 ° C. for 30 minutes. Priority 4 parts concentrated sulfuric acid (d = 1.84) was added and the mixture heated to 7O then 30 minutes ⁰ C. After cooling, contributes to the reaction mixture in about 150 parts of water and making the mixture alkaline by adding sodium hydroxide. The precipitate is filtered off, washed with water and dried. 25 parts of 2-phenyl-5- [4'-nitrophenyl] -1, 3,4-thiadiazole are obtained as pale yellow crystals with a melting point of 256 to 257 ° C.

Example 5

A solution of 26.7 parts of N-phthalylthiobenzoic acid amide and 20 parts of p-methoxybenzoic acid hydrazide and 120 parts of N-methylpyrrolidone is ^{heated to 40 °} C. for 30 minutes. 10 parts of formic acid are added and the mixture is then heated to 70 ^° C. for 30 minutes. The reaction mixture is worked up as described in Example 4. 22 parts of 2 - phenyl - 5 - [4 '- methoxyphenyl] -1,3,4-thiadiazole are obtained as colorless crystals with a melting point of 143 to 145 ° C.

Examples

A solution of 26.7 parts of N-phthalylthiobenzoic acid amide and 25 parts of p-aminobenzoic acid hydrazide in 130 parts of N-methylpyrrolidone is ^{heated to 40 °} C. for 30 minutes. 10 parts of p-toluenesulfonic acid are added and the mixture is then heated to 70 ^° C. for 30 minutes. The reaction mixture is worked up as described in Example 4. 20 parts of 2-phenyl-5- [4'-aminophenyl] -1,3,4-thiadiazole are obtained as almost colorless crystals with a melting point of 171 to 173.degree.

. Example 7

A solution of 26.7 parts of N-phthalylthiobenzoic acid amide and 20 parts of salicylic acid hydrazide in 150 parts of N-methylpyrrolidone is 30 minutes heated to 40 ° C. 15 parts of p-toluenesulfonic acid are added and the mixture is then heated to 70 to 80 ° C. for 30 minutes. After cooling down, you wear it the reaction mixture in about 150 parts of water and make the mixture by adding 2 n-soda solution alkaline. After filtering off, 24 parts of 2-phenyl-5- [2'-hydroxyphenyl] -1,3,4-thiadiazole are obtained as colorless crystals with a melting point of 206 to 208 ° C.

For example 1 8

A solution of 26.7 parts of N-phthalylthiobenzoic acid amide and 20 parts of isonicotinic acid hydrazide in 100 parts of N-methylpyrrolidone is ^{heated to 40 °} C. for 30 minutes. Mari adds 15 parts of p-toluenesulfonic acid and then heats the mixture to 70 ° C. for 30 minutes. The reaction mixture is worked up as described in Example 4. 20 parts of 2-phenyl-5- [y-pyridyl] -1, 3,4-thiadiazole are obtained as colorless crystals with a melting point of 181 to 183 ° C.

B e i s ρ i e 1 9

A solution of 26.7 parts of N-phthalylthiobenzoic acid amide and 20 parts of acetic acid hydrazide in 130 parts of N-methylpyrrolidone is heated to 30 ° C. for 30 minutes. 15 parts of p-toluenesulfonic acid are added and the mixture is then heated to 70 ^° C. for 30 minutes. The reaction mixture is worked up as described in Example 4. 11 parts of 2-methyl-5-phenyl-1,3,4-thiadiazole are obtained as colorless crystals with a melting point of 102 to 103 ^° C.

Example 1 10

Used instead of 20 parts of acetic hydrazide 15 parts of cyanoacetic acid hydrazide and the rest of the procedure as indicated in Example 9 is obtained 11.5 parts of 2-cyanoethyl 5-phenyl-1,3,4-thiadiazole are obtained as colorless crystals with a melting point of 115.degree.

Example 1Γ '

A solution of 30 parts of N-phthalylthiobenzoic acid amide and 30 parts of benzoic acid hydrazide in 200 parts by volume of chlorobenzene is first heated to 50 ^° C. for 30 minutes, then to 100 ^° C. for 30 minutes and finally to 150 ^° C. for 30 minutes. The solvent is distilled off under reduced pressure. The residue is introduced into 2η sodium hydroxide solution and filtered. The filter residue is washed out with water and dried. After recrystallization from ethyl alcohol, 22 parts of 2,5-diphenyl-1,3,4-thiadiazole are obtained as colorless crystals with a melting point of 140 to 141.degree.

Example 12

A solution of 50 parts of methyl dithiobenzoate and 50 parts of benzoic acid hydrazide in 100 parts of N-methylpyrrolidone are heated to 150 ° C. for 2 hours. After cooling down, you wear it

Reaction mixture in about 150 parts of water, makes the mixture by adding caustic soda alkaline and filtered. The filter residue is washed with water and dried. You get 35 parts of 2,5-diphenyl-1,3,4-thiadiazole as colorless crystals with a melting point of 137 to 139.degree.

Example 113

A solution of 30 parts of N-phthalylthiobenzoic acid amide and 30 parts of benzoic acid hydrazide in 250 parts of glacial acetic acid is initially applied for 2 hours 50 ° C and then heated to 100 ° C for 1 hour. After cooling, the conversion mixture is carried in about 750 parts of water and filtered off from the precipitate. The filter residue is washed with 2 η sodium hydroxide solution and then with water and dries it. 18 parts of 2,5-diphenyl-1,3,4-thiadiazole are obtained as colorless crystals with a melting point of 140 to 141 ° C.

Example'14

A mixture of 26.7 parts of N-phthalylthiobenzoic acid amide, 25 parts of 1-aminoanthraquinone-2-carboxylic acid hydrazide and 150 parts of N-methylpyrrolidone is heated to 40 ° C. for 1 hour. 15 parts of p-toluenesulfonic acid are added and the mixture is then heated to 80 ^° C. for 1 hour. After the reaction mixture has cooled, the precipitate is filtered off, washed with methanol and dried. This gives 27 parts of 2- [l'-amino-2'-anthraquinonyl] -5-phenyl-l, 3,4-thiadiazole as a red crystal with a melting point of 306 to 31o ⁰ C. The compound of violet dyes cotton vat in blaustichigroten shades .

B e i s ρ i e 1 15

A mixture of 26.7 parts of N-phthalylthiobenzoic acid amide, 28.6 parts of 1,4-diaminoanthraquinone-2-carboxylic acid hydrazide and 200 parts of N-methylpyrrolidone is ^{heated to 40 to 50 °} C. for 30 minutes. 5 parts of concentrated sulfuric acid (d = 1.84) are added and the mixture is then heated to 80 ° C. for 1 hour. After the reaction mixture has cooled, the precipitate is filtered off, washed with methanol and dried. 27 parts of 2-fl ', 4'-diamino-2'-anthraquinonyl] -5-phenyl-1,3,4-thiadiazole are obtained as dark blue crystals with a melting point of 277 to 278 ^° C.

Example 16

A mixture of 22.8 parts of N, N'-Diphthalyldithioterephthalsäurediamid, 23.2 parts of 1-aminoanthraquinone-2-carboxylic acid and 200 parts of N-methylpyrrolidone is heated for 30 minutes from 40 to 5O ⁰ C. Was added 20 parts of p-toluenesulfonic acid added and then the mixture was heated for 1 hour at 8O ⁰ C. After cooling, the reaction mixture is filtered from the precipitate, washed with methanol and dried. 22.5 parts of the compound of the formula are obtained

NH ₂ .

H ₂ N as red crystals which do not melt ^{up to 350 ° C.} The compound dyes cotton from a blue vat in shades of blue-tinged red.

- ■ Example -17

A solution of 16 parts of m-Cyanbenzoesäurehydrazid and 24 parts of N-Phthalylthiobenzoesäureamid in 100 parts of dimethylformamide is heated to 40 ⁰ C so long as it is until they become yellow. That is

ίο the case after about 1 to 2 hours. Then 8 parts of p-toluenesulfonic acid are introduced and the mixture is heated to 100 ^° C. for 15 minutes. After cooling, the reaction mixture is worked up as indicated in Example 4. 18 parts of 2-phenyl-5- [3'-cyanophenyl] -1, 3,4-thiadiazole are obtained as colorless crystals with a melting point of 177 to 178.degree.

Example 18 ⁿ

A solution of 30 parts of N-phthalyl-p-chlorthiobenzoesäureamid and 25 parts of p-Nitrobenzoesäurehydrazid in 180 parts of dimethylformamide is heated at 50 ⁰ C for so long, until they become colorless. Then transmits to 15 parts of p-toluenesulfonic acid and the mixture heated 20 minutes 8O ⁰ C. After cooling, the reaction mixture as described in Example 4, worked up. 28 parts of 2 - [p - nitrophenyl] - 5 - [p - chlorophenyl] -1,3,4-thiadiazole are obtained as pale yellow crystals with a melting point of 242 to 244 ° C. . . :.

The N-phthalylp-chlorothiobenzoic acid amide used as starting material is prepared as follows: A solution of 200 parts of phthalyl chloride in 300 parts of acetone is allowed to flow into a solution of 130 parts of p-chlorothiobenzoic acid amide in 700 parts of N-methylpyrrolidone over the course of 2 hours and the reaction mixture is stirred then 6 hours at room temperature. The reaction mixture is introduced into about 2000 parts of a mixture of ice and water. After filtering, the filter residue is washed with water and methanol and dried. This gives 210 parts of N-Phthalylp-chlorthiobenzoesäureamid as red-violet crystals of melting point 213-215 ⁰ C.

Example 1 19

A solution of 30 parts of N-phthalyl-p-chlorthiobenzoesäureamid and 23 parts of benzoic acid hydrazide in 150 parts of N-methylpyrrolidone is heated to 4O ⁰ C so long as it is until they become colorless.

This is the case after about 1 hour. Are then added 15 parts of p-toluene sulfonic acid added and heated the reaction mixture 20 minutes 7O ⁰ C. After cooling, the reaction mixture is worked up as described in Example 4. FIG. 23 parts of 2-phenyl-5- [p-chlorophenyl] -1, 3,4-thiadiazole are obtained as colorless crystals with a melting point of 181 bis

Example 20

A solution of 30 parts of N-phthalyl-p-methoxythiobenzoesäureamid and 30 parts salicylic in 200 parts of N-methylpyrrolidone is heated for 1 hour at 6O ⁰ C. 15 parts of p-toluenesulfonic acid are then added and the mixture is heated to 100 ^° C. for 30 minutes. After cooling, the reaction mixture is worked up as described in Example 7. 20 parts of 2- [o-hydroxyphenyl] -5- [p-methoxyphenyl] -1,3,4-thiadiazole are obtained as colorless crystals with a melting point of 187 to 189.degree.

IO

The N-phthalylp-methoxythiobenzoic acid amide used as the starting material is prepared by replacing 130 parts of p-chlorothiobenzoic acid amide starting from 130 parts of p-methoxythiobenzoic acid amide and otherwise as in the last one Paragraph of example 18 described works. 200 parts of N-phthalyl-p-methoxythiobenzoic acid amide are obtained as red-violet crystals with a melting point of 157 to 159 ° C.

Example 21

A solution of 30 parts of N-phthalyl-p-methoxythiobenzoesäureamid and 25 parts of "benzoic acid hydrazide in 200 parts of N-methylpyrrolidone is heated as long as at 50 ⁰ C until it became colorless. Then there was 12 parts p-toluene sulfonic acid added and heated the Mixture 30 minutes to 100 ^° C. After cooling, the reaction mixture is worked up as described in Example 4. 18 parts of 2-phenyl-5- [p-methoxyphenyl] -1, 3j4-thiadiazole are obtained as colorless crystals with a melting point of 143 bis 145 ° C. The compound is identical to the compound prepared according to Example 5.

B e i s ρ i e 1 22

A solution of 8.7 parts of succinic and 30 parts of N-Phthalylthiobenzoesäureamid in 100 parts of N-methylpyrrolidone is initially heated for 1 hour at 4O ⁰ C and then 15 minutes at 50 ⁰ C. Add 15 parts of p-toluenesulfonic acid _w added and the mixture heated 30 minutes 8O ⁰ C. After cooling, the reaction mixture is worked up as described in Example 4. FIG. 12 parts of the compound of the formula are obtained

N-N

Ν — Ν

CH ₂ - CH ₂

35 terephthalic acid diamide in 100 parts of N-methylpyrrolidone is allowed to flow in a solution of 20 parts of phthalyl chloride in 100 parts of acetone and the mixture is then stirred for 4 hours at room temperature. The transfer mixture is introduced into about 500 parts of a mixture of ice and water, and the feed residue is filtered and washed with methanol and dried. 20 parts of Ν, Ν'-diphthalyldithioterephthalic acid diamide are obtained as red-violet crystals with a melting point of 295 to 300.degree.

Example 24

A solution of 18 parts of thioformylbenzoylhydrazine in 40 parts of concentrated sulfuric acid (d = 1.84) is left to stand for 30 minutes at room temperature and then added dropwise to about 800 parts of water with cooling. After filtration, the feed residue is washed with a little dilute sodium hydroxide solution and dried. 11 parts of 2-phenyl-1,3,4-thiadiazole are obtained as colorless crystals with a melting point of 38 to 40.degree.

The thioformylbenzoyhydrazine used as the starting material is obtained as follows: A mixture of 10 parts of dithioformic acid, 5 parts Benzoic acid hydrazide, 20 parts of 1 η sodium hydroxide solution and 30 parts of water are stirred at 20 ° C. for 1 hour. The reaction mixture is then treated with acetic acid, filtered and the filter residue is washed with Water and dry it. 5 parts of thioformylbenzoylhydrazine are obtained as colorless crystals of Melting point 135-137 ° C.

Claims (1)

Claim: Process for the preparation of 1,3,4-thiadiazoles the formula 40 as yellow crystals. The compound dyes cotton from a brown vat in greenish yellow tones. The N, N'-diphthalyldithioterephthalic acid diamide used as the starting material is prepared as follows: To a solution of .10 parts dithio- N- Il
Ri-C Il CR ₂ as colorless crystals with a melting point of 195 to 197 ^° C. Example 23 45 A mixture of 23 parts of Ν, Ν'-diphthalyldithioterephthalic acid diamide, 24 parts of anthraquinone-2-carboxylic acid hydrazide and 300 parts of N-methylpyrrolidone is ^{heated to 50 °} C. for 1 hour. Are then added 10 parts of p-toluene sulfonic acid added and the mixture heated for 1 hour at 100 ⁰ C. After cooling, it is filtered and the Füterrückstand washed with methanol and dried. 16 parts of the compound of the formula are obtained wherein Ri is a hydrogen atom, an optionally by nitro, amino, hydroxy, carboxy or nitrile groups substituted alkyl, cycloalkyl, aralkyl, aryl or a heterocyclic Rest or the rest N
XC ■ N Il C - A - 55 60 where A is an alkylene or phenylene radical and X is an aromatic radical, and R _{2 is} an alkyl, cycloalkyl, aralkyl, aryl radical or the radical substituted by nitro, amino, hydroxy, carboxy or nitrile groups N- ■ N 65 where A and X have the meaning given above, is characterized by 709 647/541 11 12 net that one monothiodiacylhydrazines of the formula ,. ■ ■ ■ NH —— NH Ri-C CR ₂ wherein Ri and R _{2 have} the aforementioned meaning and also Ri NH- NH NH NH -AC CX and R ₂ -A-C CX Vso '■' So ' where A and X have the meaning given above. have, can be, or the implementation mix Journal of the American Chemical Society, from a corresponding carboxylic acid hydrazide, Vol. 77 (1955), p. 400; and a corresponding thioacylating agent Journal of the Chemical Society, 1949, p. 1163 in a solvent and in the presence of a 20 to 1167; Acid to 20 to 150 ⁰ C, preferably to 50 to RC Elderfield, heterocyclic compounds, 100 ⁰ C, heated. Vol. 7 (1961), pp. 589, 590. 709647/541 9.67 θ Bundesdruckerei Berlin