(2RS,3RS)-l-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-l-yl)pentan-3-ol
Paclobutrazol
CAS: 76738-62-0
Molecular Formula: C15H20ClN3O
(2RS,3RS)-l-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-l-yl)pentan-3-ol - Names and Identifiers
(2RS,3RS)-l-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-l-yl)pentan-3-ol - Physico-chemical Properties
| Molecular Formula | C15H20ClN3O |
| Molar Mass | 293.8 |
| Density | 1.22 |
| Melting Point | 165-166°C |
| Boling Point | 460.9±55.0 °C(Predicted) |
| Flash Point | 232.6°C |
| Solubility | Cyclohexanone 18%, methanol 15%, acetone 11%, dichloromethane 10%, xylene 6%, propylene glycol 5%, water, 35ppm. |
| Vapor Presure | 2.72E-09mmHg at 25°C |
| Appearance | off-white to beige solid |
| Color | White to Almost white |
| Maximum wavelength(λmax) | ['218nm(lit.)'] |
| Merck | 14,6984 |
| pKa | 13.92±0.20(Predicted) |
| Storage Condition | 0-6°C |
| Sensitive | Hygroscopic |
| MDL | MFCD01678673 |
| Physical and Chemical Properties | Melting point 165-166°C |
| Use | Is a new type, high efficiency, low toxicity plant growth regulator, and has a broad spectrum of bactericidal effect |
(2RS,3RS)-l-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-l-yl)pentan-3-ol - Risk and Safety
| Risk Codes | R22 - Harmful if swallowed R21/22 - Harmful in contact with skin and if swallowed. R11 - Highly Flammable |
| Safety Description | 36 - Wear suitable protective clothing. |
| UN IDs | UN1325 4.1/PG 2 |
| WGK Germany | 3 |
| RTECS | XZ4803300 |
| HS Code | 29339900 |
| Hazard Class | 4.1 |
| Packing Group | II |
(2RS,3RS)-l-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-l-yl)pentan-3-ol - Upstream Downstream Industry
| Raw Materials | Dichloroethane 4-Chlorobenzyl chloride Potassium borohydride Potassium carbonate Ethyl Alcohol |
(2RS,3RS)-l-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-l-yl)pentan-3-ol - Reference
| Reference Show more | 1. Yuan, Li, Jin, LAN, he, Shan, et al. Mitigative effect of Indian Piriform spore on overuse of plant growth regulators in rice [J]. Fujian Journal of Agricultural Sciences 2020 v.35;No.197(04):44-51. 2. [IF = 5.753] Suhong Li et al."Mechanisms of High Concentration Valine-Mediated Inhibition of Leach Tree Shoot Growth." Front Plant Sci. 2020; 11: 603067 3. [IF = 6.291] Hui Liu et al."Study on endocrine disruption effect of paclobutrazol and uniconazole on the thyroid of male and female rats based on lipidomics."Ecotox Environ Safe. 2022 Apr;234:113386 4. [IF=4.116] Zhang Hongliang et al."Role of gibberellin and its three GID1 receptors in Jasminum sambac stem elongation and flowering."Planta. 2022 Jan;255(1):1-16 |
(2RS,3RS)-l-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-l-yl)pentan-3-ol - Introduction
Paclobutrazol is a new plant growth regulator, which can inhibit the production of gibberellin derivatives and reduce the division and elongation of plant cells.
Last Update：2022-10-16 17:28:32
(2RS,3RS)-l-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-l-yl)pentan-3-ol - Reference Information
| NIST chemical information | information provided by: webbook.nist.gov (external link) |
| EPA chemical substance information | information provided by: ofmpeb.epa.gov (external link) |
| plant growth regulator | paclobutrazol is a kind of inhibitory triazole plant growth regulator, in 1984 by the British buneimen (ICI) the company was first developed successfully. It is an inhibitor of endogenous gibberellin synthesis, which can obviously weaken the apical growth advantage, promote the lateral bud (tillering) breeding, stem diameter, plant dwarf compact. It can increase the content of chlorophyll, protein and nucleic acid, reduce the content of gibberellin in plants, reduce the content of indole acetic acid and increase the release of ethylene. It works mainly through root uptake. The amount of absorption from the leaves is small, not enough to cause morphological changes, but can increase production. The control effect of paclobutrazol on crop growth has high application value. For example, with 100 mg/L of liquid medicine 150 soaked rice seeds 100 36 hours, and then Bud sowing, or in rice leaves 1 heart, with 100 mg/L of liquid medicine 1500/ha, the seedling field with spray drainage water can achieve the effect of length control and Tiller promotion, and the length control rate and Tiller promotion rate are generally 30% and 50 ~ 100%. In addition, 30 days before heading of rice, with 300 mg/L paclobutrazol per hectare 900 foliar spray, has a good anti-lodging effect. The quality of rape seedlings treated with paclobutrazol was significantly improved, and the frost resistance was greatly increased after transplanting. Paclobutrazol also makes peach, apple, citrus plants dwarf, shoot control and the effectiveness of early fruit. Herbs and Woody flowers treated with paclobutrazol, compact plant type, More ornamental value. Paclobutrazol had a longer lasting period in soil. So that the medicinal plots after harvest should pay attention to tillage, in order to reduce the inhibition of subsequent crops. |
| mechanism of action | can be absorbed by plants through roots, stems and leaves. The root uptake of paclobutrazol runs through the xylem to the top of the plant, mainly upward transport. After absorption of the leaves, the movement is very slow, and the growth of the plant or branch is inhibited by the multi. This effect is mainly achieved by inhibiting the synthesis of gibberellin. In the process of inhibiting the synthesis of gibberellin, it mainly inhibits the middle three processes from the process of mevalonic acid → kauriene → kauriferol → kaurialdehyde → kauriferic acid → gibberellin, it does not inhibit the synthesis of kaurene, and does not affect the process of Kauric acid. By inhibiting the synthesis of gibberellin, reducing cell division and elongation. It can not only reduce the number of GA synthesized in plants, but also reduce the content of IAA and increase the content of endogenous ethylene ABA and cytokinin. Paclobutrazol can effectively regulate and control plant growth and development at the hormone level by changing the hormone balance in plants. Its main physiological effects are as follows. 1. Change the level of endogenous hormones in crops and delay growth. The height and Internode growth of plants are mainly regulated by GA. Paclobutrazol inhibits gibberellin synthesis, thus delaying growth, inhibiting Internode growth and dwarfing plants. If paclobutrazol was applied in seedling stage, the content of gibberellin was only 8.4% (CK) on average. However, the content of gibberellin decreased by 65.2% (CK) after paclobutrazol was applied in rape seedlings. Paclobutrazol had an effect on the content of indole acetic acid in the body of the plant, and the application on the seedling was 43% of the non-application; The application on the rape was 87.1% lower than the control. After treated with paclobutrazol, the content of endogenous abscisic acid increased significantly, and the content of abscisic acid in rice was 552.4% of the control, and the content of abscisic acid in rape increased by 88.7%. Paclobutrazol also regulates the ethylene release rate of the plant. In 3.1 of rice leaf age, the application of 15% paclobutrazol 2.5/hm2, in 7.1 of leaf age sampling determination, ethylene release rate increased significantly, to 137.4% without paclobutrazol. Paclobutrazol also had an effect on the content of endogenous cytokinin in plants. For example, the application of 15% paclobutrazol 3.75/hm2 in rice seedling stage increased by 118.4% in average compared with the application of no paclobutrazol during 10~40 days after application. |
| note | paclobutrazol remains in the soil for a long time, and must be tillage after harvesting, in order to prevent the inhibition of the latter. Pay attention to protection, avoid contact with the eyes and skin. If splash into the eye to use a large amount of water to rinse, at least 15 minutes. The skin should be washed with soap and water. If the eyes or skin irritation continues to occur, you can see a doctor to take treatment. Such as the wrong take, should prompt Vomit, go to the hospital for treatment. This product should be stored in a cool and ventilated place, storage should not be close to food and feed, do not let children access. No specific antidote, symptomatic treatment according to symptoms. |
| analytical method | the product can be analyzed by gas chromatography or high performance liquid chromatography (ICI method). Reagents Used: paclobutrazol standard (content greater than 99.5%); Dibutyl phthalate (analytically pure, 10 mg/mL ethanol internal standard solution); Anhydrous ethanol. Instrument use: nitrogen and phosphorus detector; Column: 1/8 "glass column, 6 ft long stationary phase: OV-17% carrier: chromolore WHP 80~100 mesh. Operating conditions: Carrier gas flow rate: nitrogen, 30ml/min; Hydrogen flow rate: 3ml/min; Air flow rate: 90ml/min; Furnace temperature: initial temperature: 220 ℃; Initial time: 2 min; ramp rate: 30 °c/min; Final temperature: 250 °c; Final Time: 2 min. Inlet Temperature: 250 ° C; Detection temperature: 300 ° C; Paper speed: 1/min; Injection volume: 100 μl; Retention time: 2.5 minutes. |
| degradation metabolism | paclobutrazol enters the body from the root, and the effect of spraying on the plant is minimal, mainly into the soil surface of the liquid is absorbed by the root system, the operation is in the catheter, not in the screen. In the distribution of the body, the leaves accounted for 50.3%, the root accounted for 44.3%, and rarely left in the stem. The half-life of paclobutrazol in plants varies depending on the conditions, and is usually 3 to 12 months. The degradation rate of paclobutrazol in plants varies with different parts of the plant. According to the experiment, 9 days after the treatment of peach, still 71.5% in The Root, 41.5% ~ 68.1% in the stem, only 7.8% ~ 12.2% in the leaves. The main component remaining in the apple is PP333 (about 50%), mostly in the peel, other components are diol, acid and triazolyl acetone. The half-life in soil was 3 months. Paclobutrazol can be quickly excreted in mammals, in sheep, about 90% of the dose is excreted, only a small amount in milk and other tissues. The main components of the final residual material are PP333 and diols. In hens, approximately 88% of the dose was excluded from the body within 14 days of feeding. Glycols (mainly in the bound state) are the major components remaining in the egg yolk and liver. |
| allowable residues | a joint meeting of experts of the World Food Organization (FAO) and the United Nations (WHO) has set an allowable residue level of 0.05mg/kg for nuts, kernel and fruit is 0.2mg/kg, China's fruit experts after toxicological studies proposed to allow residues of 0.01mg/kg (refers to the crop). |
| toxicity | Acute oral LD50 in rats was 2000mg/kg (male), 1300mg/kg (female), mouse acute oral LD50 was 490mg/kg (male), 1200mg/kg (female), Rabbit acute oral LD50 was 840mg/kg (male), 940mg/kg (female). Rat and rabbit acute percutaneous LD50>1000mg/kg. Rats acute inhalation lc504.79 mg/L (male) (4H), 3.13mg/L (female) (4H). It is irritating to the skin and eyes of rats and rabbits. Rats were fed with 250mg/kg for 2 years and dogs were fed with 75mg/kg for 1 year. No mutagenicity. Rainbow trout lc5027.8 mg/L (96H), carp lc5023.5 mg/L (48h), Daphnia LC50>7900mg/L. Low toxicity to bees, LD50>0.002mg/only. |
| Use | azole plant growth regulator, endogenous gibberellin biosynthesis inhibitor. It has the function of hindering the growth of plants and shortening the pitch. For example, rice can improve the activity of indole acetic acid oxidase in rice, reduce the level of endogenous IAA in rice seedlings, significantly control the growth rate of rice seedling tips, promote leaf division, make the leaves dark green, develop the root system, and reduce lodging, increasing ear and increasing yield. General length control rate was 30%, leaf promotion rate was 50% ~ 100%. The yield increase rate reached 35%. For peach, pear, citrus, Apple and other fruit trees can be "control the tip of trapped", so that the tree type dwarf. After treatment with paclobutrazol, chrysanthemum, geranium, poinsettia and some ornamental shrubs, plant type is adjusted, more ornamental value. Cultivation of greenhouse vegetables such as tomato, rape and other strong seedling effect is obvious. Breeding of late rice seedlings, in the one-leaf stage, dry the rice field water, with 100 ~ 300mg/L paclobutrazol solution 15kg/100m2 uniform spraying. Control the seedling length, with 100mg/L paclobutrazol solution 150kg, 100kg of rice seed soaking 36H, germination sowing, 35d seedling age, seedling height not more than 25cm. It is used to control the shoots of fruit trees, usually in late autumn or spring, each fruit tree is injected with 300mg/L paclobutrazol solution 500mL, or 1/2 along the radius of the crown around the soil surface layer 5 ~ 10cm uniform irrigation, with 15% wettable powder 98g/100m2. With 1.2 ~ 1.8g active ingredient/100m2 paclobutrazol, the basal ganglia of winter wheat can be shortened and the stem can be strengthened. Paclobutrazol on rice blast, cotton red rot, cereal smut, wheat and other crops of rust, powdery mildew also have control effect, can also be used as fruit preservatives. In addition, in a certain amount, some single and dicotyledonous weeds also have inhibitory effect. paclobutrazol is a new type of plant growth regulator, which can inhibit the formation of gibberellin derivatives and reduce the division and elongation of plant cells. It is easily absorbed by the root, stem and leaf, conducts through the xylem of the plant, and has bactericidal effect. Gramineae plants have a wide range of activities, can make the plant stem internodes become short, reduce lodging, increase yield. It is a new type of plant growth regulator with high efficiency and low toxicity, and has a broad spectrum of bactericidal effect |
| production method | raw material consumption quota: kanazon 930kg/t, 1,2, 4-triazole 540kg/t, P-chlorobenzyl chloride 960kg/t. A preparation method of 1,2, 4-triazole and 1-chloro-3, 3-dimethyl-2-butanone as raw materials, synthesis of α-1,2, 4-triazole-3, 3-dimethyl-2-butanone and p-chlorobenzyl are condensed to produce α-p-chlorobenzyl -1,2, 4-triazole-3, 3-dimethyl-2-butanone was then reduced with sodium borohydride to yield paclobutrazol. This method is easy to obtain raw materials, less steps, the main disadvantage is that the reduction reaction using sodium borohydride (potassium), resulting in high cost. Literature reports on the use of sodium bisulfite (Na2S2O4), sodium dithionite powder as reducing agent in alkaline medium (NaHCO3) and selected solvent or solvent system (water-methanol, 6:1, volume ratio) during the reaction, paclobutrazol was prepared. A working example was as follows: 0.03mol of NaHCO3 was mixed with 60ml of water and heated with stirring until dissolved. Then the chlorazolone was fully dissolved in 10ml of methanol, and then the aqueous NaHCO3 solution was added at one time. The resulting turbid reaction mixture was heated and stirred, and the sodium hydrosulfite (0.03mol) was added after reflux. In 6h, 6 times were added, and 2H was added. After completion of the reaction, paclobutrazol is obtained by cooling, Suction filtration, washing with water and drying, and has a melting point of 146-154 °c. The crude product was recrystallized from acetonitrile to a white solid, m. P. 162~163 ℃, the purity of the product was 98.23%, and the yield was 98.81% based on chlorazolone. The preparation method 2 uses p-chlorobenzaldehyde and 3, 3-dimethyl-2-butanone as raw materials to generate the corresponding alkenone, which is reacted with 1,2, 4-triazole by hydrogenation and bromination, finally, it was reduced with sodium borohydride to obtain paclobutrazol. The raw materials of this method are easy to obtain, but the process is longer. Preparation Method 1-(p-chlorophenyl)-2-(1,2, 4-triazol-1-yl) propionyl chloride is reacted with tert-butyl magnesium bromide, and then reduced with sodium borohydride to obtain paclobutrazol. Although the production steps of this method are few, the raw material is rare, and it is easy to hydrolyze, and it needs to be carried out under anhydrous conditions. |
| category | pesticide |
| toxicity grade | poisoning |
| Acute toxicity | oral-rat LD50: 1300 mg/kg; Oral-mouse LD50: 490 mg/kg |
| flammability hazard characteristics | toxic nitrogen oxides and chloride gases from combustion |
| storage and transportation characteristics | The warehouse is ventilated and dried at low temperature; It is stored and transported separately from food raw materials |
| extinguishing agent | dry powder, foam, sand |
Last Update：2024-04-09 21:11:58
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Raw Materials for (2RS,3RS)-l-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-l-yl)pentan-3-ol