SU755785A1 - Method of preparing benzothieno-/3,2-b/-benzothiophene or its 2,7-substituted derivatives - Google Patents

Description

The invention relates to a new method for producing benzothieno (3,2-b) benzothiophene or its 2,7-disubstituted derivatives of the general formula

, -OrHg ’'

where B is hydrogen, chlorine, bromine, amino or nitro,

which possess biological activity, and can therefore find application in medicine and in agriculture, and can also be used as intermediates in the synthesis of dyes.

A method of producing benzothieno (3,2-b) benzothiophene is known, which consists in the fact that benzylidene chloride is reacted with elemental sulfur at 290-300 ° C, followed by extraction with 80% acetic acid. acid. The yield of the target product after recrystallization from glacial acetic acid is 61% [1].

The disadvantages of this method include the relatively low yield of the target product, as well as the impossibility of obtaining by this method benzothiene derivatives (3,2-b) -benzothiophene with substituents such as amino or nitro group that cannot withstand heating with sulfur at high temperature.

The aim of the invention is to increase the yield and expansion of the range of target products by synthesizing new compounds.

According to the invention, a new method for the preparation of benzothieno (3,2-b) benzothiophene or its 2,7-disubstituted derivatives of the general formula is described, namely, that the corresponding stilbene-2,2 ^ -disulfonyl chloride is subjected to sequential treatment with 55-57% hydroiodic acid at 80-100 ° C and dehydrating agent during boiling.

Sulfur or bromine, or hydroiodic acid, or chloranil, or Ν-bromosuccinimide, or pyridinium perbromide bromide is preferably used as a dehydrating agent. Preferably also the process

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in an organic solvent, and the first stage is carried out in glacial acetic acid, and the second in carbon tetrachloride or toluene, or dioxane, or xylene, or acetic acid.

The process can also be carried out in such a way that the corresponding stilbene-2,2-disulfonyl chloride is treated only with an excess of hydroiodic acid, which leads to a simplification of the process, since it proceeds in one stage.

The yield of the target products reaches up to 96%. In this method, get the majority

New compounds are all substituted benzothieno (3,2-b) benzothiophene.

Example 1. To a solution of 3.77 g (0.01 mol) of stilbene-2,2'-disulfonyl chloride in 280 ml of glacial acetic acid at 100 ° C is added 28 ml (0.2 mol) of concentrated hydroiodic acid and stirred for 4 hours at 100 ° C. Then the mixture is diluted with water, treated with sodium hydrosulfite solution, the precipitate is filtered off, washed with water, dried and obtain 1.68 g (70%) of benzothieno (3,2-b) benzothiophene with m.p. 212213 ° С (from carbon tetrachloride).

Example 2. To 4.07 g (0.01 mol) 4,4'diaminostilbene-2,2 ¹ -disulfonyl chloride add 42 ml (0.03 mol) of hydroiodic acid and after stirring for 3 h at 90 ° C leave on 12 hours at 20 ° C. Diluted twice with water, treated with an aqueous solution of sodium hydrosulfite, neutralized with 25% ammonia solution. The precipitate was filtered off, washed with water, dried, and 1.67 g (20%) of 2,7-diamino-4b, 9b-dpihydrobenzothieno (3,2-b) benzothiophene, t. Pl. 217-218 ° C (from chloroform).

A. A mixture of 2.7 g (0.01 mol) of 2,7-diamino-4b, 9b-dihydrobenzothieno (3,2-b) benzothiophene and 5 g (0.16 mol) of sulfur is heated for 3 hours at 160-180 ° C, the melt is cooled, crushed, extracted with 80% acetic acid, the extract is diluted with water, the precipitate is filtered, dried, to obtain 1.05 g (39%)

2,7-diaminobenzothieno (3,2-b) benzothiophene, so pl. 256-157 ° C (from acetic acid).

B. 2.72 g (0.01 mol) of 2,7-diamino-4b, 9bdagidrobenz otieno (3,2-b) - benzothiophene is dissolved in 360 ml of dioxane, 3 ml (0.04 mol) of trifluoroacetic anhydride are added at 50 ° C, shaken, the precipitate is filtered off, washed with water, dried, and 3.6 g (78%) of ditrifluoroacetamido-4b, 9b-benzothieno (3,2-b) benzothiophene, t. J. 286-287 ° C (from acetic acid).

To a boiling solution of 4.67 g (0.01 mol) of ditrifluoroacetamide in 200 ml of acetic acid add 3.5 g (0.011 mol) of bromide

pyridinium perbromide, cool, precipitate. filtered, washed with water, dried and obtained 4.25 g (92%) of 2,7-ditrifluoroacetamido-benzothieno (3,2-b) benzothiophene, m.p. 420-422 ° C (from pyridine).

A solution of 4.62 g (0.01 mol) of 2,7-ditrifluoroacetamido benzothieno- (3,2-b) benzothiophene in 50 ml of pyridine is mixed with a solution of 8 g (0.2 mol) of caustic soda in 20 ml of water and 200 ml of ethanol a, leave for 12 h at 20 C. Then the solution is diluted with water, the precipitate is filtered off, dried and receive

2.2 g (82%) of 2,7-diaminobenzothieno (3,2-b) benzothiophene, m.p. 256-257 ° C (from chlorobenzene)

Found,%: C 62.72; H 3.60; N 10.11;

5 23.57

SiNuNgZg ·

Calculated,%: C 52.19; H 3.73; N 10.36;

5 23.72.

EXAMPLE 3 To a solution of 3.77 g (0.01 mol) stilbene-2,2 ^ζ -disulfohlorida in 230 ml of glacial acetic acid at 100 ° C was added 28 ml (0.2 mol) of concentrated yodastovodorodnoy acid and left for 12 hours at 20 ° C. The mixture is then diluted with water, treated with sodium hydrosulfite solution, the precipitate is filtered off, washed with water, dried, and 1.74 g (72%) of a mixture of 4L, 9H-dihydrobenzothieno (3,2-b) Zenzothiophene (t. pl 146-147 ° C), after chromatography-. separation of silica gel with benzeneheptane, 1: 2 and benzothieno (3,2-b) benzothiophene.

A solution of 2.40 g (0.01 mol) 4b, 9b-dihydro: benzothieno- (3.2 - b) benzothiophene and 5 g (0.02 mol) of chloranil in 200 ml of anhydrous m-xylene is boiled for 10 h, evaporated, the residue is recrystallized from carbon tetrachloride to obtain 0.9 g (38%) of benzothieno (3,2-b) benzothiophene, m.p. 217-218 ° C (when conducting treatment with pyridinium perbromide bromide, the yield of the compound is 98% (see Example 2B).

Found,%: C 69.23; H 3.36; δ 26.68 "

C1 ₄ H ₈ 3 ₂ .

Calculated.%: C 69.96; H 3.36; δ 26.68;

Example 4. To a solution of 4.46 g (0.01 mol) 4.4 ^G- dichlorostilben-ι 2,2 * -disulfonyl chloride in 230 ml of glacial acetic acid at 100 ° C add 56 mi (0.4 mol) of hydroiodic acid and leave for 12 h at 20 ° C. Then it is diluted with water, treated with sodium hydrosulfite solution, the precipitate is filtered off, washed with water, dried and yielded 2.79 g (90%) of 2,7-dachlor-4b, 9b-dihydrrbenzothieno1: (3,2-b) benzothiophene with mp. . 216-217 ° C (from chloroform).

A mixture of 3.1 g (0.01 mol) of 2,7-dichloro-4b, 9b dihydrobenzothieno (3,2-b) benzothiophene, 2 g

five

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(0.025 mol) of bromine in 200 ml of carbon tetrachloride is boiled for 6 h, evaporated and recrystallized from acetic acid, to obtain 1.6 g (52%) of 2,7-dichlorobenzothieno (3,2-b) benzothiophene, m.p. 257-258 ° С (when carrying out 5 treatments with pyridinium perbromide bromide, the yield of the compound is 96%, see example 2B).

., Found,%: C 54.48; H 1.87; 5 21.01;

C 22.66C ₁₄ H ₆ 3 ₂ C1 ₂ , ¹⁰

Calculated,%: C 54.38; H 1.96; 8 20.74;

From 22.93,

Example 5. To a solution of 4.67 g (0.01 mol) of 4,4 - dinigrostilben-2,2'-disulfonyl chloride in 600 ml of glacial acetic acid ¹⁵ at 100 ° C is poured 42 ml (03 mol) of concentrated hydroiodic acid and leave for 12 hours at 20 ° C. The precipitate is filtered off, washed with an aqueous solution of sodium hydrosulfite, dried and obtain 2.5 g of ²⁰ (75%) 4,4-dinitrostilben-2,2 ^/ -ditol with so pl. 200-201 ° C (from chlorobenzene).

To a boiling suspension of 3.34 g (0.01 mol)

4,4'-dinitrostilben-2,2 * -dithiol in 350 ml of acetic acid is added a solution of 8 g of ²⁵ (0.025 mol) pyridinium perbromide bromide, heated for another 5 hours, the precipitate is filtered, washed with water, dried and 2.64 g are obtained ( 79%) 2,7-dinitrobenzothieno (3,2-b) 'benzothiophene with m. Pl. 375-377 ° C (from chloroform - 30 mA.

Found,%: C 51.15; H 1.64; N 838;

5 20.01.

From 1 ₄ Nb Ν ₂ Ο ₄ 3 ₂ .

¹ Calculated,%: C 50.95; H 1.83; N 8.49; 35

3 19.43.

Example 6. To a solution of 535 g (0.01 mol) of 4,4 -dibromostilben-2,2-disulfonyl chloride in 600 ml of acetic acid at 80100 ° С add 56 ml (0.4 mol) of iodisto- ⁴⁰ hydrochloric acid, heat another 5 h and leave for 12 h at 20 ° C. Then the precipitate is filtered off, treated with an aqueous solution of sodium hydrosulfite, washed with oh, dried and get 2.77 g (69%) of 4,4 -dibrom-45 stilbene-2,2 ^/ -dithiol with m.p. 175-177 ° C (from chlorobenzene).

A mixture of 4 g (0.01 mol), 4,4-dibromostilben2,2-dithiol, 7.1 g (0.04 mol) of-bromosuccinide, 0.5 g (0.025 mol) of benzene peroxide and 50 to 100 ml of carbon tetrachloride boil

6 h, evaporated, the residue is extracted with benzene, filtered, the filtrate is evaporated, crystallized from benzene, 3.2 g (79%) of 2,7-dibromobenzothieno (3,2-b) benzothiophene are obtained with m.p. 300-301 ° C (from benzene).

Found,%: C 42.90; H 132; 5 15.81;

Br 39.98.

With 14N6 ZgVg,

Calculated,%: C 42.25; H 132; 8 16.11;

Br 40.12.

Claims (4)

Claim 1. The method of producing benzothieno (3,2-b) -b-. zothiophene or its 2,7-disubstituted derivatives of the general formula where B is hydrogen, chlorine, bromine, amino or nitro, characterized in that, with a chain of increasing yield and expanding the range of target products, the corresponding stilben 2,2 ** - disulfonate is subjected to sequential processing of 55-57% hydroiodic acid at 80-100 ° C and a dehydrating agent during boiling. 2. The method according to π. 1, characterized in that as a dehydrating agent use sulfur or bromine, or hydroiodic acid, or hloranpl, or Ν-bromsuction imid or perbromide bromide pyridinium. 3. The method according to claim 1, characterized in that the process is carried out in an organic solvent, such as glacial acetic acid or carbon tetrachloride, or toluene, or dioxane. 4. A method according to claims 1 and 3, characterized in that, in order to simplify the process, the corresponding stilben-2,2-dasulfonyl chloride is treated only with an excess of hydroiodic acid. Sources of information taken into account in the examination 1. Copyright certificate № 169127, cl. C 07 ϋ 333/52, 26.03.64 (prototype).