CS274096B1 - 6-acetamido-3-alkyl-2-benzothiazolinones - Google Patents

Abstract

As yet unknown 6-acetamido-3-alkyl-2-benzothiazolinones were prepared. The synthesis of the given compound is performed by reaction of the potassium salt of 6-acetamido-2-benzothiazolinone with reactive alkyl halides in a boiling mixture of ethanol and water. The new compounds are characterised by formula I, where R represents ethyl, n-butyl or benzyl. The compounds regulate the growth of plants.<IMAGE>

Description

(57) Hitherto unknown 6-acatamido-3-alkyl-2-benzothiazolinones were prepared. The synthesis of said compounds is effected by the reaction of drastic selenium 6-acetamido-2-benzothiazolone 8 with reactive alkyl halides in a mixture of ethanol and water at boiling.

CH ₃ -CO-NH-.

CS 274096 Bl

The present invention provides 6-acetamido-3-alkyl-2-benzothiazolinones.

3-substituted 6-nitro-2-benzothiazolinene derivatives have been shown to be effective as plant growth regulators / D'Amico 3.0. US Pat. 4,282,029 (1981), Sidóová, E., Slanáriková. V., Mitterhauszer, C. and Kralova, K., PV 8564-88 / and as herbicides / D * Amico 3.3. US Pat. No. 4,185,990 (1980) //.

Now doe gold, that so far unknown compounds of the formula

where R is ethyl, n-butyl or benzyl have a stimulating effect on the growth of fresh matter and on the content of synthesized chlorophyll in the above-ground part of maize (Zea mays L);

At the same time, the process for the preparation of the above compounds was confused by reacting the potassium salt of 6-acetamido-2-benzothiazolinone with alkyl iodides, respectively. with benzyl chloride in ethanol / water boiling.

The following examples illustrate, but do not limit, the preparation and properties of the compounds of the invention.

Example 1

Preparation of 6-acetamido-3-ethyl-2-benzothiazolinone

6-Acetamido-2-benzothiazolinone (6.3 g, 0.03 mol) was dissolved in a solution of potassium hydroxide 33 (2.0 g, 0.03 mol) in a mixture of water (10 cm) and ethanol (22 cm) . Ethyl iodide (5.5 g, 0.035 mol) was added to the solution, the reaction mixture was refluxed for 3 hours and then left overnight at 5 ° C. The crude product, m.p. 191 DEG-195 DEG C. in an amount of 6.35 g (89.7%),

The sample for analysis was recrystallized from ethanol / water 2; 1 using activated carbon. Pure 6-acetamido-3-ethyl-2-benzothiazolinone with m.p.

192.5-195 ° C.

MW 236.30 for C ₁₁ H ₁₂ N ₂ 0 ₂ S calculated%: C 55.91 H 5.12 N 11.86 S 13.57 found%: 55.65 5.11 12.03 13.51

Example 2

Preparation of 6-acetamido-3-n-butyl-2-benzothiazolinone

The preparation was carried out according to Example 1 using n-butyl iodide (6.5 g, 0.035 mol) and using 40 cm of ethanol.

After the reflux was complete, the reaction mixture was decolourised with activated carbon. Pure 6-acetamido-3'-n-butyl-2-benzothiazolinone, m.p. 160 DEG-162.5 DEG C. in an amount of 6.2 g (78.3%).

MH + 264.35 Ex C ₁₃ H ₁₆ N ₂ 0 ₂ S calculated%; C 59.07 H 6.10 N 10.60 S 12.13 Found%: 58.78 6.00 10.80 11.85

Example 3

Preparation of 6-acetamido-3-benzyl-2-benzothiazolinone

CS 274096 Bl

The preparation was carried out according to Example 1 using benzyl chloride (4.05 g, 0.032 mol). A crude product with m.p. 179 DEG-183 DEG C. in an amount of 8.6 g (96.2%).

The sample for analysis was purified by dissolving the substance in ethyl acetate, decolourizing the charcoal, and precipitating pure 6-acetamido-3-benzyl-2-benzothiazolinone of m.p. Mp 180-182 ° C.

Mw = 298.37

For C ₁₆ h ₁₄ N ₂ 0 ₂ s

computed %: C 64.41 H, 4.73 9.39 S, 10.75 % found 1 64.20 4.79 9.41 10.79 Example 4 effect of the compounds of the invention for growth fresh mass and chlorophyll content

in above-ground part of maize / Zea mays L. /

Table for example 4

Effect of compounds according to the invention on the growth of fresh mass and the chlorophyll content of the above-ground corn

compound according to invention Concentration mol.dm ^-3 Percentage increase compared to control Contents chlorophyll I * 0 05 ´ the weight of the green part of the germ O / control / 100.0 - 5.7 100.0 or 3.8 1.10 ⁶ 112,5 i 6,5 98.2 and 2.4 1 1.10 ⁷ 121.2 and 5.1 96.2 or 3.7 1.10 “ ⁸ 108.5 or 6.8 114.8 - 3.2 1.10 ^-9 112.4 i 0.6 115.7 - 7.3 1.10 ^-6 127.9 or 3.3 110.1 - 9.3 2 1.10- ⁷ 110.8 - 7.3 114.5 - 1.0 1.10 “ ⁸ ·· 109.5 8 8.5 123.1 or 1.7 1.10 ⁹ 111,5 t 4,0 114.0 6 6.0 1.10 ⁶ 118.6 and 7.3 105.9 or 2.3 3 1.10- ⁷ 109.0 4,4 4.4 105.1 i 0.6 1.10 ⁸ 119.2 - 6.2 118.6 ± 2.9 1.10 ⁹ 105.0 - 4.4 116.8 - 0.3

To test the increase in fresh mass as well as the content of synthesized chlorophyll in the above-ground maize, the corn seeds were pre-germinated in the dark in rollers of twisted filter paper moistened with distilled water for 3 days. The germs were then placed in hydropenias containing nutrient solution according to Hoogland / Hoogland, DR, Snyder, Wg, Hoogland's inorganic salt solution AZ supplement in Hewitt, E.3./Ed/Sand and water culture methods in the study of plant nutrition - Nutrition Commonwealth agric. Bur., Farnham Royal, p. 189/1966 / alone, respectively. with the addition of compounds

CS 274096 B1 according to the invention in a nutrient solution and placed in a culture box with an illumination mode of 14 hours light, 10 hours dark. The effect of the compounds of the invention was tested at a concentration of 1.10 to 1.10 mol, dm. After 6 days of culture at room temperature, the weight of the green germ and the chlorophyll content were determined.

At the test concentrations of the compounds of the invention, ea showed a stimulatory effect on both the growth of fresh mass and the level of synthesized chlorophyll in the above-ground part of the maize.

Example 5

An effect of the compounds according to the invention for the growth and synthesis of chlorophyll of green algae

Algae of Chlorella vulgaria were grown by stationary cultivation at 25 ° C under a light regime of 16 hours evetlo, 8 hours of darkness in a collecting medium according to Setlik / Setlik I.: Annual Report of Algolog. Lab. for 1967, 71-140, Trebon 1968 /. The test substance was added to the culture medium in dimethylformamide solution (total solvent content in the culture medium was 1%) and the same volume of solvent was added to the control samples. Culture flasks and inoculated with an accurate volume of homogeneous algae suspension. After 7 days of culture, the volume of the culture medium was supplemented with des-. The absorbance at 660 nm (proportional to the number of algae cells) and the chlorophyll content after its extraction were measured in aqueous suspension (equilibrated with water) and in the cell suspension. dimethylformamide from centrifuged riaa cells / Inskeep, W.P., Bloom, P.R. Plant Physiol. 77 (2), 483-5 s_1985 //.

Regulatory efficacy on algae was monitored in a concentration range of 1.10 ⁴ to 1.10 ^- 1 mol.dm ³ . Whereas those of Example 1 and 3 showed only a stimulating effect on the observed range of concentrations, the compounds of Example 2 at a concentration of ⁴ M l.lo zlatíí inhibition of the synthesis of chlorophyll. The effect on algal chlorophyll growth and synthesis, expressed as a percentage of the values found in the co-cultured control samples, is shown in the table of Example 5,

Table for example 5

Effect of compounds of the invention on growth and content of synthesized chlorophyll of green algae

Example compound

Concentration mol.dm ³

K o n t r o lyy

Chlorophyll content

Absorbance at 660 nm

1.10 ” ⁴ 1.10 ⁵ 1.10 ⁷ 97.7 and 2.9 110.5 - 4.5 115.4 - 1.2 93.5 t 8.4 98.3 t 4.3 105,5 t 1,6 ⁹ 104.5 - 16.30 111.7 tl, l Í.IO ¹¹ 113.1 or 4.8 108,3 t 2,9 1.10? ⁴ 73.2 or 1.6 95,9 t 1,1 1.10 ⁵ 107.7 Í12.1 101.1 tl0,8 Í.IO ^-7 96.0 8 8.4 107.9 t 9.3 1.10 ⁹ 99.2 1 7.2 96,7 Ϊ14.1 ¹¹ 104.0 i 9.5 108,6 t 4,6 ⁴ 110.0 til, 7 113.0 -25.0 1.10 ^-5 120.4 tu, 5 112.2 t13, l

CS 274096 Bl

1 2 3 4 3 1.10 ⁷ 109.4 or 11.4 115.9 or 6.6 1.10 ⁹ 101.6 and 10.2 114.7 1 1.3 1.10 ¹¹ 92.3 1 2.3 95.6 £ 5.4

Of note is the fact that the compounds of the invention are of a novel, hitherto unknown structure, and have a regulatory effect on the growth and synthesis of chlorella of algae Chorella vulgaris.

Especially significant is the fact that the compounds according to the invention stimulate the increase of fresh-6 -9 mass and the chlorophyll content of the above-ground maize portion at a concentration of 1.10 to 1.10 mol.dm

The compounds of the invention may be used as an active ingredient in preparations for stimulating the growth of plants and green algae, alone or in admixture with other substances, as an intermediate for saler synthesis.

Claims (2)

BACKGROUND OF THE INVENTION 1i 6-Acetamido-3-alkyl-2-benzothiazolinones of the formula wherein R is ethyl, n-butyl or benzyl. 2. A process for the preparation of a compound according to claim 1, which comprises reacting the potassium salt of 6-acetamido-2-benzothiazolinone with ethyl iodide, n-butyl iodide or benzyl chloride in a mixture of ethanol and water at boiling.