JP2767318B2 - 5-Aminolevulinic acid alkyl ester or salt thereof, process for producing the same, and herbicide containing the same as active ingredient - Google Patents

Description

The present invention relates to an alkyl 5-aminolevulinate or a salt thereof, a method for producing the same, and a herbicide containing these as an active ingredient.

[Problems to be solved by conventional technology and invention]

It has been disclosed that 5-aminolevulinic acid, a natural amino acid, has low toxicity and acts as a biodegradable light-requiring herbicide (Japanese Patent Publication No. Sho 61-502814). That is, 5-aminolevulinic acid is a precursor of tetrapyrrole, and when 5-aminolevulinic acid is sprayed on a plant, the production of tetropyrrole is promoted. Therefore, active oxygen is generated by the catalytic action of tetrapyrrole in the presence of light. It occurs and leaves the leaves of plants and the like.

Generally, it is a necessary condition that practically used herbicides adhere to plants by spraying and kill the plants themselves. However, extremely hydrophilic compounds such as 5-aminolevulinic acid have poor adhesion to plants, and most of them fall into the soil when sprayed, and therefore may not contribute much to the production of tetrapyrrole. However, as a result, the herbicidal activity was low, such as the re-emergence of the leaves even after the leaves of the plant were bleached and died, and were not practically satisfactory. Also,
Since the herbicidal activity was limited only to the vicinity of the point of attachment, the non-uniform application caused immediate re-emergence.

Accordingly, an object of the present invention is to provide a novel compound having safety, biodegradability, and selectivity and having practical herbicidal activity, a method for producing the same, and a herbicide using the same.

[Means for solving the problem]

Under such circumstances, the present inventors have conducted intensive studies, and as a result, have found that alkyl 5-aminolevulinate or a salt thereof has a new herbicidal activity and excellent spread on plants that are not found in 5-aminolevulinic acid. The present inventors have found that the present invention has properties, and have completed the present invention.

That is, the present invention provides a compound represented by the general formula (I) (Wherein, R ¹ represents an alkyl group having 2 or more carbon atoms) or a salt thereof, a method for producing the same, and a herbicide containing these as an active ingredient.

In the 5-aminolevulinic acid alkyl ester of the present invention, r ¹ is an alkyl group having 2 or more carbon atoms. When used as a herbicide, r ¹ has 4 to 24 carbon atoms in view of herbicidal activity.
And especially an alkyl group of 4 to 16 is preferred. Specific examples include an ethyl group, a propyl group, an n-butyl group,
Linear alkyl groups such as pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, lauryl, palmityl, stearyl; isopropyl, isobutyl, sec-butyl, t
ert-butyl group, isopentyl group, neopentyl group, 2
And branched-chain alkyl groups such as -ethylhexyl group and 2-octyldecyl group.

Examples of the salts include inorganic salts such as hydrochloric acid, sulfuric acid, nitric acid, and nitrous acid; and salts of organic acids such as acetic acid, lactic acid, citric acid, and butyric acid.

The alkyl 5-aminolevulinate or a salt thereof of the present invention can be obtained by a general method for synthesizing an amino acid ester, and can be produced, for example, according to the following reaction formula.

(Wherein, R ¹ has the same meaning as described above, and r ² represents a hydrogen atom or an amino-protecting group).

That is, by reacting an alcohol (III) with 5-aminolevulinic acid (II) or a reactive derivative thereof, whose amino group may be protected, and removing an amino-protecting group, if any, is present. , 5-aminolevulinic acid alkyl ester or its salt (I) is produced.

Examples of the reactive derivative of 5-aminolevulinic acid whose amino group may be protected include an acid halide, a mixed acid anhydride and the like. As such a reactive derivative, an isolated product may be used as a raw material, but it may be used as a reaction mixture without isolation.

In the case of using unprotected 5-aminolevulinic acid as a raw material, a condensing agent, for example, thionyl chloride is added dropwise to the alcohol (III) at about 0 to 20 ° C. under normal pressure.
Add aminolevulinic acid.

Here, thionyl chloride is used to convert 5-aminolevulinic acid into an acid chloride. For this purpose, instead of thionyl chloride, phosphorus trichloride, phosphorus pentachloride, phosphoryl chloride, oxalyl chloride and the like can be used. However, since these react easily with alcohol (III) or the amino group of 5-aminolevulinic acid to deactivate, they are reacted with a 5-aminolevulinic acid derivative having a protected amino group to synthesize an acid chloride, and then alcohol (III). Is preferably reacted.

Although 5-aminolevulinic acid itself can be used as a raw material, the polycondensation reaction between the raw materials may take precedence over esterification, and in order to prevent this, it is necessary to keep the raw material concentration low. Therefore, it is more effective to use a salt such as 5-aminolevulinic acid hydrochloride.
If the reaction temperature is lower than about 0 ° C., the starting alcohol (III) may be solidified. If the reaction temperature is higher than about 20 ° C., thionyl chloride or the like may decompose and evaporate at this point. It is preferable to keep the range. Specific examples of the alcohol (III) that can be used include:
1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol And their isomers such as 2-butanol, 2-methyl-1-propanol and 2-methyl-2-
Branched alkyl alcohols such as propanol and 2,2-dimethyl-1-propanol can also be used.

Next, a means such as a nitrogen seal is applied so that neither the reaction system nor the raw material contains moisture, and the temperature is gradually raised to about 60 to 90 ° C, preferably about 70 to 80 ° C. The reaction is kept for about 1 to 3 hours in the range to complete the reaction. Here, when the reaction temperature is about 60 ° C. or less, it takes time to complete the reaction,
If the temperature is about 90 ° C. or higher, the reaction system may be colored. Therefore, it is preferable to maintain the above temperature range.

After the completion of the reaction, sulfur dioxide, hydrogen chloride, unreacted thionyl chloride, and the like, which are reaction by-products, are distilled off under reduced pressure of about 10 to 30 mmHg. Next, a solvent having a polarity lower than that of alcohols, for example, a solvent such as ether, hexane or chloroform is added to crystallize the mixture, followed by filtration to obtain a salt of the 5-aminolevulinic acid alkyl ester of the present invention.

Further, by subjecting this to ion exchange using an anion exchange resin or the like, the alkyl 5-aminolevulinate of the present invention or other salts can be obtained.

The above method is a good method in that the number of reaction steps is small, but when an tertiary alkyl group such as an alkyl group having about 10 or more carbon atoms or a tert-butyl group is introduced as an ester, the reaction activity of the alcohol is low. In some cases, the reaction does not proceed smoothly. In such a case, the amino group of 5-aminolevulinic acid or a salt thereof is protected with an appropriate protecting group, and then esterification is performed. It is preferable to carry out the method because the yield is higher.

As the protecting group (R ² ) for the amino group in this method,
Amino group-protecting groups used in ordinary peptide synthesis are used, for example, carbonyl compounds such as acetyl, benzoyl, tert-butoxycarbonyl and benzyloxycarbonyl can be used. Is preferred.

In order to synthesize 5-aminolevulinic acid having an amino group protected as a raw material, for example, 5-aminolevulinic acid or a salt thereof is made into an aqueous solution together with a weak base such as sodium hydrogencarbonate or potassium hydrogencarbonate, and stirred at room temperature under stirring. It is preferable to react by adding an ether solution of an active carbonyl compound such as benzyloxycarbonyl chloride.

Here, any solvent may be used as long as it is insoluble in water and does not react with a carbonyl compound such as benzyloxycarbonyl chloride. In addition to ether, n-hexane, benzene and the like can be used.

After completion of the reaction, the aqueous layer was washed with ether or the like after removing the ether feed, and then acidified to about pH 1 to 3 with about 1 to 6 N hydrochloric acid, and the product was treated with ethyl acetate, chloroform, dichloromethane, etc. Is extracted. The extracted organic layer is dried using anhydrous sodium sulfate, anhydrous magnesium sulfate, or the like, and then the solvent is evaporated to dryness under reduced pressure, whereby amino groups having sufficient purity for the following esterification reaction are protected. -Aminolevulinic acid, for example 5-benzyloxycarboxamidolevulinic acid, is obtained.

The obtained 5-aminolevulinic acid having a protected amino group, for example, 5-benzyloxycarboxamidolevulinic acid, is prepared in a solvent having an azeotropic property with water, such as benzene, toluene, and carbon tetrachloride, in an alcohol (III ) And a non-volatile acid catalyst such as phosphoric acid or sulfuric acid, and then heating and refluxing, and separating the generated water with a Dean-Stark apparatus or molecular sieve can easily lead to the ester.

A trace amount of the acid catalyst used in the reaction is removed by washing the reaction solution with water, followed by drying in the same manner as described above, followed by evaporating to dryness under reduced pressure to give an amino group-protected ester of 5-aminolevulinic acid, for example, 5 -Benzyloxycarboxamido levulinic acid alkyl ester is obtained. The product can be purified by recrystallization using n-hexane, isooctane or the like.

The elimination of the protecting group of the alkyl ester of 5-benzyloxycarboxamidolevulinic acid is carried out by a usual hydrogenolysis reaction,
For example, it can be achieved by allowing a trace amount of a catalyst having palladium supported on carbon to react in a solvent such as methanol, ethanol, propanol, or ethyl acetate under a hydrogen atmosphere at 1 atm or in a hydrogen stream at room temperature.

After removing the catalyst by filtration, the reaction product is evaporated to dryness under reduced pressure to obtain the desired alkyl 5-aminolevulinate. If the reaction is carried out in the presence of an acid such as hydrogen chloride or the like, an acid is added after the reaction and evaporated to dryness to obtain the product as a salt such as 5-aminolevulinic acid alkyl ester hydrochloride.

Since the 5-aminolevulinic acid alkyl ester and the salt thereof of the present invention have excellent spreadability when made into an aqueous solution, they have a feature of spreading thinly and uniformly on the surface when sprayed on a plant surface. This is because the 5-aminolevulinic acid alkyl ester and the salt thereof of the present invention have an amino group which is a hydrophilic portion and an alkyl group which is a hydrophobic component in both ends of the molecule, and thus have a surfactant activity. It is estimated to be.

Conventionally, when a compound having poor adhesion to plants is used as a herbicide by showing a high aqueous solution such as an amino acid such as 5-aminolevulinic acid, an aliphatic quaternary ammonium salt, a polyoxyethylene alkyl ether, a polyoxyethylene A spreading agent such as alkyl phenyl ether is added to secondarily adhere to plants.
-The aminolevulinic acid alkyl ester and its salt have the property of directly adhering to the plant surface by themselves, so that a spreading agent is not particularly required and is more efficient.

Furthermore, the 5-aminolevulinic acid alkyl ester and the salt thereof of the present invention are remarkably superior to 5-aminolevulinic acid also in herbicidal activity. That is, the herbicidal effect of 5-aminolevulinic acid causes secondary plant death from whitening and withering limited to the sprayed surface. In addition to the sprinkling part, buds and the like that are not sprayed also die, so that even if the sprinkling is uneven, it has an effect of preventing re-generation. this is,
It is presumed that the 5-aminolevulinic acid alkyl ester and its salt efficiently adhere to the surface of the sprayed part, so that it is absorbed by the adhered part and moves in the plant.

When the 5-aminolevulinic acid alkyl ester of the present invention and a salt thereof are used as a herbicide, the dosage form is preferably used as a spraying liquid in the form of a solution, suspension or emulsion. Examples of the solvent at this time include water, lower alcohols such as methanol, isopropanol and isobutanol, ethylene or propylene glycol, acetone, xylene, kerosene, benzene, methylnaphthalene and cyclohexanone. 5 in the spray liquid
It is preferred that the content of the alkyl aminolevulinate and its salt is about 5 to 30 mmol /, particularly 15 to 25 mmol /.

Furthermore, the herbicide of the present invention is obtained by mixing and adsorbing an alkyl 5-aminolevulinate or a salt thereof with a filler such as talc, diatomaceous earth, silica, or calcium nitrate of various particle sizes to form a wettable powder. This can be suspended in water and sprayed.

The application amount of the herbicide of the present invention is about 30 to 30 per square meter.
Preferably, the volume is about 50 ml.

In addition, other herbicides, surfactants and spreading agents can be used in combination with the herbicide of the present invention as long as the effects of the present invention are not impaired.

〔The invention's effect〕

The novel 5-aminolevulinic acid alkyl ester and the salt thereof of the present invention have good spreadability to plants and, at the same time, herbicidal activity is not limited only to the vicinity of the adhesion spread. And herbicidal activity is very high.

In addition, the secondary products generated by hydrolysis of the ester bond of the compound of the present invention are both 5-aminolevulinic acid and alcohols, while having the biodegradability and selectivity of conventional 5-aminolevulinic acid. It is not inferior to 5-aminolevulinic acid also in terms of safety. Further, the compound of the present invention can be produced by a simple means,
Since even 10 or more alkyl groups can be efficiently introduced as an ester, they can be industrially advantageously produced.

〔Example〕

Next, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 0.5 ml of thionyl chloride was added dropwise to 3 ml of 1-octal under ice cooling, and then 500 mg of 5-aminolevulinic acid hydrochloride was added. While stirring, raise the reaction temperature from room temperature to 80 ° C.
And kept for about 2 hours. After confirming the completion of the reaction, the mixture was allowed to cool to room temperature, and then volatile components were distilled off under reduced pressure of 10 mmHg. Then hexane is added to crystallize the product,
Precipitated, then filtered, washed, and dried to obtain 826 mg of octyl 5-aminolevulinic acid hydrochloride,
The yield was 99%.

From the results of ¹ H-NMR and infrared absorption spectrum (Nujol method), the obtained product was confirmed to have the following structural formula. The measured values and the structural formula are shown below. ^{1 H-NMR (90MHz, CDCl} 3) δ (ppm): 0.87 (t, 3H, CH 3) 1.00-1.75 (b, 12H, CH 2 6) 4.05 (t, 2H, COOCH 2) 2.45-3.05 (m , 4H, COCH ₂ CH ₂ CO) 4.30 (b, 2H, COCH ₂ N) Infrared absorption spectrum ^{(nujol, cm -1) 1730 (C =} 0) 2860 (-CH 2 -) 2950 (-CH 2 -) Structural formula Example 2 (1) As a result of carrying out in the same manner as in Example 1 except that 1-hexanol was used instead of 1-octanol as a raw material,
662 mg of 5-aminolevulinic acid hexyl ester hydrochloride was obtained, and the yield was 88%.

From the results of ¹ H-NMR and infrared absorption spectrum (Nujol method), the obtained product was confirmed to have the following structural formula. ^{1 H-NMR (90MHz, CDCl} 3) δ (ppm): 0.90 (t, 3H, CH 3) 1.10-1.80 (b, 4H, CH 2 4) 2.45-3.12 (m, 4H, COCH 2 CH 2 CO) 4.05 (t, 2H, COOCH ₂ ) 4.30 (b, 2H, COCH ₂ N) Infrared absorption spectrum ^{(nujol, cm -1) 1730 (C =} 0) 2850 (-CH 2 -) 2920 (-CH 2 -) Structural formula (2) Next, the 5-aminolevulinic acid alkyl ester hydrochloride obtained in (1) is ion-exchanged to give 5
-An aminolevulinic acid alkyl ester was obtained.

That is, an anion exchange resin was packed in a glass column with an inner diameter of 10 mm to a height of about 20 cm,
Flow about 100 ml, completely OH type, then completely eliminate sodium hydroxide with ion-exchanged water, put 400 mg of 5-aminolevulinic acid hexyl ester hydrochloride dissolved in about 10 ml of ion-exchanged water at the top of the column, The mixture was passed through the column for about 10 minutes while adding exchange water. 5
-Hexyl aminolevulinate hydrochloride is ion-exchanged during passage through the column to obtain an aqueous solution of hexyl 5-aminolevulinate, which is then concentrated and dried under reduced pressure to obtain 339 mg of hexyl 5-aminolevulinate. Was.

Example 3 The procedure of Example 1 was repeated, except that 1-octanol was used instead of 1-octanol as the starting material. As a result, 665 mg of heptyl 5-aminolevulinic acid hydrochloride was obtained, and the yield was 83%. Was.

From the results of ¹ H-NMR and infrared absorption spectrum (Nujol method), the obtained product was confirmed to have the following structural formula. ^{1 H-NMR (90MHz, CDCl} 3) δ (ppm): 0.88 (t, 3H, CH 3) 1.10-2.85 (b, 10H, CH 2 5) 2.43-3.15 (b, 4H, COCH 2 CH 2 CO) 4.05 (t, 3H, COOCH ₂ ) 4.07−4.70 (b, 2H, COCH ₂ N) Infrared absorption spectrum ^{(nujol, cm -1) 1730 (C =} 0) 2850 (-CH 2 -) 2920 (-CH 2 -) Structural formula Example 4 As a result of performing in the same manner as in Example 1 except that 1-octanol was used instead of 1-octanol, 647 mg of 5-aminolevulinic acid nonyl ester hydrochloride was obtained, and the yield was 74%. Was.

From the results of ¹ H-NMR and infrared absorption spectrum (Nujol method), the obtained product was confirmed to have the following structural formula. ^{1 H-NMR (90MHz, CDCl} 3) δ (ppm): 0.89 (t, 3H, CH 3) 1.05-1.80 (b, 14H, CH 2 7) 2.45-3.10 (b, 4H, COCH 2 CH 2 CO) 4.05 (t, 2H, COOCH ₂ ) 4.05−4.60 (b, 2H, COCH ₂ N) Infrared absorption spectrum ^{(nujol, cm -1) 1730 (C =} 0) 2850 (-CH 2 -) 2930 (-CH 2 -) Structural formula Example 5 As a result of carrying out in the same manner as in Example 1 except that 1-decanol was used instead of 1-octanol, 642 mg of 5-aminolevulinic acid decyl ester hydrochloride was obtained, and the yield was 70%. Was.

From the results of ¹ H-NMR and infrared absorption spectrum (Nujol method), the obtained product was confirmed to have the following structural formula. ^{1 H-NMR (90MHz, CDCl} 3) δ (ppm): 0.90 (t, 3H, CH 3) 1.00-1.95 (b, 16H, CH 2 8) 2.35-3.10 (b, 4H, COCH 2 CH 2 CO) 4.05 (t, 2H, COOCH ₂ ) 4.05-4.59 (b, 2H, COCH ₂ N) Infrared absorption spectrum ^{(nujol, cm -1) 1730 (C =} 0) 2850 (-CH 2 -) 2930 (-CH 2 -) Structural formula Example 6 (1) 5-aminolevulinic acid hydrochloride (500 mg) and sodium hydrogencarbonate (650 mg) were dissolved in water (5 ml), and the mixture was stirred at room temperature with ether (5 ml) and benzyloxycarbonyl chloride (0.3).
ml was added. After stirring for about 2 hours, the generation of carbon dioxide gas was stopped, and benzyloxycarbonyl chloride 0.3m
l and 325 mg of sodium carbonate were added. (The reason why the reaction is performed twice is to allow the reaction to proceed gradually.) Further, after stirring for about 2 hours to confirm the generation of carbon dioxide gas and the completion of the reaction, the aqueous layer is washed with ether. Wash twice, 6N
After adjusting the pH to 1.5 using hydrochloric acid, acidic organic substances were extracted with ethyl acetate.

The extract layer was dried by adding anhydrous sodium sulfate to adsorb water and then removed by filtration.The solvent was evaporated to dryness under reduced pressure.The obtained solid was recrystallized with a mixed solvent of ethyl acetate and hexane to give pale yellow crystals 630.3. mg was obtained.

300 mg was taken from the obtained crystals, dissolved in 30 ml of benzene, and heated under reflux using a Dean-Stark apparatus together with 0.088 ml of 1-dodecanol and 5 ml of p-toluenesulfonic acid hydrate. Was confirmed by thin layer chromatography (TLC).

The reaction solution was washed with a saturated aqueous solution of sodium hydrogencarbonate, and then washed with water. The organic layer was dried over anhydrous sodium carbonate, filtered to remove sodium carbonate, and evaporated to dryness under reduced pressure. Obtained. Recrystallization of the crystals with hexane gave 370.3 mg of 5-benzyloxycarboxamidolevulinic acid dodecyl ester,
The yield was 71% over 5-aminolevulinic acid.

The product obtained ^- that from the results of H-NMR and infrared absorption spectrum (nujol) the structure below was confirmed. ^{1 H-NMR (90MHz, CDCl} 3) δ (ppm): 0.87 (t, 3H, CH 3) 1.27 (s, 18H, - (CH 2) 9 -) 1.45-1.80 (b, 2H, -CH 2 - ) 2.67 (s, 4H, -CO -CH 2 -CH 2 -CO-) 3.90-4.25 (m, 4H, N-CH 2 -, - COO-CH 2 -) 5.15 (s, 2H, Ph-CH 2 −) 5.25−5.60 (b, 1H, NH) 7.36 (s, 5H, Ph) Infrared absorption spectrum (Nujol method, cm ⁻¹ ) 3310 (NH) 1725 (C = 0) 1690 (C = 0) Structural formula (2) The obtained 5-benzyloxycarboxamidolevulinic acid dodecyl ester (300 mg) was dissolved in methanol (10 ml), and thereto was added 1N hydrochloric acid (1 ml) and 5% palladium-supported carbon catalyst (10 mg), and the mixture was stirred at room temperature under a hydrogen atmosphere. .

After confirming the completion of the reaction, the catalyst was removed by filtration and evaporated to dryness under reduced pressure. The obtained crystals were treated with ethyl acetate-
Recrystallization from a mixed solvent of hexane gave 260.1 mg of 5-aminolevulinic acid dodecyl ester hydrochloride, and the yield was 9
4%.

The obtained crystal was confirmed to have the following structure by ¹ H-NMR and infrared absorption spectrum (Nujol method). ¹ H-NMR (90 MHz, CDCl ₃ ) δ (ppm): 0.87 (t, 3 H, CH ₃ ) 1.27 (s, 18 H, — (CH ₂ ) ₉ −) 1.44-1.75 (b, 2 H, —CH ₂ — ) 2.46-3.10 (b, 4H, -CO -CH 2 -CH 2 -CO-) 4.03 (t, 2H, -COO-CH 2 -) 4.15-4.46 (b, 1H, -NH-CO-) 7.95- _{8.45 (b, 3H, -NH 3} Cl) infrared absorption spectrum _{^{(nujol, cm -1) 3250 (-NH 3}} Cl) 1750 (C = 0) 1730 (C = 0) structural formula Example 7 The same operation as in Example 6 was carried out except that 1-hexadecanol was used instead of 1-dodecanol, and 5-benzyloxycarboxamidolevulinic acid hexadecyl ester was used.
481.7 mg and then 400 mg of this were used to give 297.1 mg of 5-aminolevulinic acid hexadecyl ester hydrochloride,
The yields were 87% and 92%, respectively.

From the results of ¹ H-NMR and infrared absorption spectrum (Nujol method), it was confirmed that each product had the following structure.

5-benzyloxycarboxamidolevulinic acid hexadecyl ester ¹ H-NMR (90 MHz, CDCl ₃ ) δ (ppm): 0.87 (t, 3 H, CH ₃ ) 1.27 (s, 28 H, − (CH ₂ ) ₁₄ −) 2.69 ( _{s, 4H, -CO-CH 2} -CH 2 -CO-) 3.90-4.22 (m, 4H, -N-CH 2 -, COO-CH 2 -) 5.12 (s, 2H, Ph-CH 2 -) 5.25 -5.65 (b, 1H, NH) 7.36 (s, 3H, Ph) Infrared absorption spectrum (Nujol method, cm ^-1 ) 3310 (NH) 1725 (C = 0) 1685 (C = 0) Structural formula 5-Aminolevulinic acid hexadecyl ester hydrochloride ¹ H-NMR (90 MHz, CDCl ₃ / DMSO-d) δ (ppm): 0.88 (b, 3 H, —CH ₃ ) 1.29 (s, 28 H, — (CH ₂ ) ₁₄ -) 2.50-2.90 (m, 4H, -CO-CH 2 -CH 2 -CO) 3.80-4.15 (m, 4H, -CO-O-CH 2 -, N-CH 2 -CO-) 8.30-8.70 ( b, 3H, NH ₃ Cl) Infrared absorption spectrum (Nujol method, cm ^-1 ) 3250 (-NH ₃ Cl) 1750 (C = 0) 1730 (C = 0) Structural formula Test Example 1 The octyl 5-aminolevulinate hydrochloride obtained in Example 1 was dissolved in distilled water to 30 mmol /, and this was sprayed on various plants at 50 ml / m ² to evaluate the effect after 4 days. evaluated. Table 1 shows the results.

As can be seen from Table 1, the herbicidal activity of octyl 5-aminolevulinate hydrochloride is highly selective for dicots.

In addition, the 5-aminolevulinic acid alkyl ester hydrochloride obtained in Examples 2 to 5 and the hexyl 5-aminolevulinate obtained in Example 2 also exhibited similar herbicidal activities.

Test Example 2 30 mmol / water solution of 5-aminolevulinic acid nonyl ester hydrochloride obtained in Example 4, 30 mmol / water solution of commercially available 5-aminolevulinic acid hydrochloride, and 30 mmol / water solution of commercially available 5-aminolevulinic acid hydrochloride A 1% mixture of commercially available spreading materials was sprayed on each cucumber seedling once using a brush once over the true leaf surface, and the results of the evaluation of the discoloration of the leaf surface one day later are shown. -2.

As can be seen from Table 2, it has an excellent herbicidal activity even when compared with a conventional herbicide to which 5-aminolevulinic acid nonyl ester hydrochloride is added.

Test Example 3 A 30 mmol / water solution of the 5-aminolevulinic acid alkyl ester hydrochloride obtained in Examples 1 to 7 and commercially available 5-aminolevulinic acid alkyl ester hydrochloride
A 30% aqueous solution of aminolevulinic acid hydrochloride mixed with 1% of a commercial spreading agent was applied to each half of the true leaves of cucumber seedlings with a brush, and the subsequent process and the state of regeneration 30 days later Are shown in Table 3.

From the results shown in Table-3, the 5-aminolevulinic acid alkyl ester hydrochloride of the present invention is slightly more operative than 5-aminolevulinic acid hydrochloride, but has an effect on the buds of the plant, and has a regrowth effect. It can be seen that it also has the effect of suppressing re-generation.

As described above, the examples and test examples are described as follows.
Aminolevulinic acid alkyl esters and salts thereof are extremely useful as herbicide components. Further, it can be used as a surfactant.

Claims (3)

(57) [Claims] 1. The compound of the general formula (I) (Wherein, R ¹ represents an alkyl group having 2 or more carbon atoms) 5-aminolevulinic acid alkyl ester or a salt thereof. 2. A compound of the general formula (II) (Wherein R ² represents a hydrogen atom or a protecting group for an amino group) and a 5-aminolevulinic acid or a reactive derivative thereof represented by the formula (III) R ¹ OH (III) (wherein R ¹ is carbon Wherein the alcohol represented by the formula (2) is reacted with an alcohol represented by the formula: wherein a protecting group for the amino group, if present, is eliminated, or the alkyl 5-aminolevulinate according to claim 1 or A method for producing the salt. 3. A herbicide as an active ingredient of the alkyl 5-aminolevulinate or the salt thereof according to claim 1.