Long-acting brassinolide compound and application thereof

Abstract

The invention provides a long-acting brassinolide compound and application thereof. The structure of the long-acting brassinolide compound is shown as a formula I or a formula II. The long-acting brassinolide compound provided by the invention is used in tea tree planting, can effectively increase the yield of tea leaves and improve the quality of the tea leaves, and has more excellent technical effects compared with other reagents.

Description

Technical Field

[0001] The invention belongs to the field of agriculture, and specifically relates to a long-acting brassinolide compound and application thereof. Background Art

[0002] Brassinolide is a type of plant endogenous hormone with a steroidal skeleton and extremely high activity. It was extracted and separated from rapeseed by the U.S. Department of Agriculture in 1979. Its structure was determined by XRD analysis and named brassinolide. Brassinolide was officially confirmed as the sixth type of plant hormone after auxin, gibberellin, cytokinin, etc. at the 16th International Plant Growth Substances Society Conference in 1998. Its chemical structure is similar to that of animal steroids, and it is this characteristic that makes it different from other plant growth hormones.

[0003] Brassinolide has a strong physiological activity, can promote plant growth and division at low concentrations, and there are traces of brassinolide in plants basically everywhere. During the entire growth and development stage of the plant, brassinolide can play its role, such as seed germination, flowering and other physiological processes. In addition, brassinolide is also very necessary for the oppression of some external conditions, such as cold, drought, land salinization and heavy metals (aluminum, nickel), etc. And studies have found that the effects of brassinolide steroids are not limited to plants at present. These steroids have shown potential medicinal effects in animal models, such as neuroprotective antioxidant properties, anti-cancer activity, anti-cholesterol effects, etc. At the same time, brassinolide is recognized as harmless to plants, the environment, humans and livestock, and is also a very beneficial agent for producing high-quality agricultural products and increasing product yields. However, the currently registered brassinolide compounds are mainly 24-epibrassinolide and 28-homobrassinolide. With its wide application in agriculture, some problems in application have also been exposed. For example, synthetic 24-epi-brassinolide and 28-homobassinolide can work well after spraying, but they will soon run out of effect. This is beneficial for crops that need to be applied quickly, but for crops that need to be applied for a long time, multiple spraying is required, which increases the use cost and labor cost.

[0004] In 1993, Takatsuto (WO9428011A1) reported a brassinolide compound with a long-lasting effect, called propionyl brassinolide. This compound has greatly improved the problem of short-term effect of brassinolide in agricultural applications. By studying the existing reports on the biological activity of brassinolide compounds, it was found that the absolute configuration of C2 and C3 is very important. Therefore, it is crucial to generate the chiral configuration of C2 and C3 in the synthetic route with high selectivity, that is, the dihydroxylation step in the synthesis of the dihydroxy compound (22E, 24S)-2α, 3α-dihydroxy-5α-stigmaster-22-ene-6-one.

[0005]

[0006] However, the problem currently faced is that there are few synthetic routes for propionyl brassinolide (related patents: CN1217338A, CN108070017A), and the existing synthetic routes basically use expensive and toxic osmium tetroxide as an oxidant, which will pollute the environment and greatly limit the application. Therefore, it is urgent to improve the process and find a preparation method that is more suitable for industrial production.

[0007] In addition, the current brassinolide industry has relatively few types of long-acting brassinolides (related patents: CN101434637A, CN1962688A, CN115716862A), which cannot meet the usage requirements of different regions and different types of crops. Therefore, it is very necessary to develop new long-acting brassinolide drugs, test their activity and develop their applications in the agricultural field. Summary of the invention

[0008] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a long-acting brassinolide compound and its application. The long-acting brassinolide compound provided by the present invention is used in tea tree planting, which can effectively improve tea yield and tea quality, and has better technical effects than other agents.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a long-acting brassinolide compound, the structure of which is shown in Formula I or Formula II:

[0011]

[0012] Wherein, R is selected from any one of substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alkynyl, substituted or unsubstituted C6-C12 aryl, and substituted or unsubstituted C6-C12 heteroaryl.

[0013] Among them, C1-C12 respectively represent that the structure contains one carbon atom, two carbon atoms, three carbon atoms, and so on. They are not repeated here. Other similar expressions have similar meanings.

[0014] Compared with agents such as brassinolide, which have a short effect time in agricultural applications and require frequent application of drugs (such as spraying every day for many days) to have significant effects, the above-mentioned long-acting brassinolide compounds with specific structures have long-lasting effects when used in tea tree cultivation. The efficacy can last for many days after application. After one or several applications, it can effectively increase tea yield and improve tea quality, and has better technical effects than other agents.

[0015] Preferably, the substituted group is selected from any one of halogen, hydroxyl, amino, nitro, thiol, aldehyde, ester, acyl, C1-C6 alkyl, C2-C6 alkenyl or C2-C6 alkynyl.

[0016] Preferably, the substituted group is selected from any one of halogen, hydroxyl, amino, nitro, thiol, aldehyde, ester, acyl, and C1-C6 alkyl.

[0017] Preferably, the R is selected from any one of a substituted or unsubstituted C1-C12 alkyl group and a substituted or unsubstituted C6-C12 aryl group.

[0018] Preferably, R is selected from any one of substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted isopropyl, substituted or unsubstituted phenyl, and substituted or unsubstituted naphthyl.

[0019] Preferably, the long-acting brassinolide compound is selected from any one of the compounds with the following structures:

[0020]

[0021] In a second aspect, the present invention provides the use of the long-acting brassinolide compound described above in the preparation of a plant growth regulator.

[0022] In a third aspect, the present invention also provides the use of the long-acting brassinolide compounds described above in tea production.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention provides a long-acting brassinolide compound with a specific structure, which can effectively increase tea yield when used in tea tree planting and has better technical effects than other agents. DETAILED DESCRIPTION

[0025] In order to further explain the technical means and effects adopted by the present invention, the technical solution of the present invention is further described below in conjunction with the preferred embodiments of the present invention, but the present invention is not limited to the scope of the embodiments.

[0026] Example 1

[0027] This example provides a method for preparing long-acting brassinolide compounds BR03 and BR04, and the specific route is as follows:

[0028]

[0029] Synthesis of (3S,8S,9S,10R,13R,14S,17R)-17-((2R,5S,E)-5-ethyl-6-methylhept-3-en-2-yl)-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopentadienyl[a]phenanthrene-3-yl methanesulfonate (5):

[0030] Stigmasterol (5.00 g, 12.1 mmol) was dissolved in dichloromethane (60 mL) and triethylamine (2.45 g, 24.2 mmol) was added. The mixture was cooled to 5 ° C, and then methanesulfonyl chloride (2.08 g, 18.1 mmol) was added dropwise. After stirring for 30 min at the same temperature, stigmasterol was completely consumed. The reaction solution was extracted with saturated saline solution, and the organic phases were combined, washed with saturated sodium bicarbonate aqueous solution and saturated saline solution, and dried over anhydrous sodium sulfate. The solvent was removed in a vacuum (40 ° C) to obtain a crude product, which was directly used in the next step without purification.

[0031] Synthesis of (1aR,3aR,3bS,5aR,6R,8aS,8bS,10R,10aR)-6-((2R,5S,E)-5-ethyl-6-methylhept-3-en-2-yl)-3a,5a-dimethylhexahydrocyclopenta[a]cyclopropyl[2,3]cyclopenta[1,2-f]naphthalen-10-ol (6):

[0032] Compound 5 was dissolved in 1,4-dioxane (60 mL) and water (20 mL), and potassium bicarbonate (2.42 g, 24.2 mmol) was then added. The reaction solution was heated to reflux (external temperature: 120 ° C) for 2.5 h. After cooling, most of the 1,4-dioxane reagent was removed under vacuum concentration, and then extracted with dichloromethane, the organic phases were combined, dried over anhydrous sodium sulfate, and concentrated under vacuum. The resulting residue was dissolved in anhydrous ethanol (15 mL) and heated to 65 ° C. The mixture was slowly cooled to ambient temperature under stirring, and then the temperature was reduced to 0 ° C. After stirring at 0 ° C overnight, the mother liquor was dried under reduced pressure at 45 ° C by filtration. A white solid product (4.13 g, yield 80%) was obtained. 1 H NMR (500 MHz, DMSO-d 6)δ5.14(dd,J=15.1,8.7Hz,1H),5.02(dd,J=15.1,8.7Hz,1H),4.09(s,1H),3.04(s,1H),2.07–1.9 9(m,1H),1.91(d,J=12.5Hz,1H),1.80–1.71(m,1H),1.63(dd,J=10.3,6.7Hz,3H),1.56–1.20(m, 10H),1.20–1.08(m,3H),1.05–0.90(m,9H),0.94–0.89(m,1H),0.82(d,J=6.1Hz,3H),0.77(q,J= 5.2,3.4Hz,7H),0.69(s,3H),0.41(t,J=3.9Hz,1H),0.23(dd,J=7.4,5.1Hz,1H).HRMS(ESI),m / z forC 29 H 49 O + [M+H] + ,Calcd:413.3778,found413.3747.

[0033] Synthesis of (1aR,3aR,3bS,5aR,6R,8aS,8bS,10aR)-6-((2R,5S,E)-5-ethyl-6-methylhept-3-en-2-yl)-3a,5a-dimethyltetradecahydrocyclopenta[a]cyclopropyl[2,3]cyclopenta[1,2-f]naphthalene-10(1H)-one (7):

[0034] Compound 6 (4.13 g, 10.0 mmol) and silica gel (200-300 mesh, 7.53 g) were added with dichloromethane (156 mL). The reaction solution was cooled to 0 ° C. Pyridinium dichromate (7.53 g, 20.0 mmol) was added in batches within 0.5 h. After addition, the reaction solution was slowly warmed to room temperature. After stirring overnight, the mixture was filtered (with diatomaceous earth), the filter cake was washed with dichloromethane, and the mother liquor was vacuum concentrated. The obtained residue was dissolved in anhydrous ethanol (20 mL) and heated to 60 ° C. The mixture was slowly cooled to room temperature under stirring, and then the temperature was reduced to 0 ° C. After stirring at 0 ° C overnight, the solid was collected by filtration and washed with a precooled (0 ° C) solution of anhydrous ethanol (5 mL). The solid was dried under reduced pressure at 45 ° C. A white solid (3.00 g, yield 66%) was obtained. 1H NMR(500MHz,Chloroform-d)δ5.12(dd,J=15.2,8.6Hz,1H),5.00(dd,J=15.2,8.6H z,1H),2.42–2.36(m,1H),2.06–1.97(m,2H),1.92–1.82(m,3H),1.81–1.72(m,1H) ,1.72–1.61(m,3H),1.57–1.44(m,5H),1.41(dd,J=28.2,3.6Hz,1H),1.33–1.11(m ,7H),1.10–0.92(m,8H),0.79(dd,J=24.7,6.5Hz,9H),0.70(s,4H).HRMS(ESI),m / z for C 29 H 47 O + [M+H] + ,Calcd:411.3621,found411.3629.

[0035] Synthesis of (5S,8S,9S,10R,13R,14S,17R)-17-((2R,5S,E)-5-ethyl-6-methylhept-3-en-2-yl)-10,13-dimethyl-1,4,5,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-6H-cyclopentadien[a]phenanthrene-6-one (3):

[0036] Compound 7 (3.00 g, 7.3 mmol), lithium bromide (634 mg, 7.3 mol) and p-toluenesulfonic acid monohydrate (PTSA) (2.48 g, 2.9 mmol) were heated to reflux (external temperature: 155°C) in N,N-dimethylformamide (49 mL) overnight. Extracted with methyl tert-butyl ether, the organic phases were combined, most of the methyl tert-butyl ether was concentrated, the residual N,N-dimethylformamide was washed with saturated brine, and then the organic phase was concentrated to dryness. The resulting residue was dissolved in anhydrous ethanol (2 mL) and heated to 65°C, and the mixture was slowly cooled to room temperature under stirring, and then the temperature was reduced to 0°C. After stirring at 0°C overnight, the solid was collected by filtration and washed with a precooled (0°C) solution of anhydrous ethanol (10.0 mL). The solid was dried under reduced pressure at 45°C. A white solid product (1.37 g, yield 46%) was obtained. 1H NMR(500MHz,Chloroform-d)δ5.68(d,J=9.5Hz,1H),5.56(d,J=9.5Hz,1H),5.14(dd,J=15.1,8.6Hz,1H ),5.02(dd,J=15.1,8.7Hz,1H),2.34(dt,J=11.6,4.2Hz,2H),2.30–2.19(m,1H),2.09–1.83(m,6H),1. 73(s,2H),1.65–1.56(m,1H),1.53(dt,J=11.8,6.2Hz,3H),1.47–1.37(m,2H),1.35–1.14(m,6H),1.02 (d,J=6.6Hz,4H),0.84(d,J=6.2Hz,3H),0.80(d,J=9.5Hz,6H),0.67(d,J=10.2Hz,6H).HRMS(ESI),m / z for C 29 H 47 O + [M+H] + ,Calcd:411.3621,found 411.3624.

[0037] Synthesis of (2R,3S,5S,8S,9S,10R,13R,14S,17R)-17-((2R,5S,E)-5-ethyl-6-methylhept-3-en-2-yl)-2,3-dihydroxy-10,13-dimethylhexahydro-6H-cyclopenta[a]phenanthrene-6-one (4):

[0038] Compound 3 (7.00 g, 17.0 mmol), N-methylmorpholine-N-oxide (4.99 g, 42.6 mmol), (DHQD)2-PHAL (265 mg, 0.3 mmol), potassium osmate dihydrate (188 mg, 0.5 mmol) were dissolved in a mixture of acetone (189 mL) and water (42 mL), and the reaction solution was vigorously stirred overnight at room temperature. The reaction solution was extracted with 10% methanol / dichloromethane, the organic phases were combined and dried over anhydrous sodium sulfate, and then concentrated in vacuo. The resulting residue was dissolved in anhydrous ethanol (20 mL) and heated to 80°C. The mixture was slowly cooled to room temperature under stirring, and then the temperature was reduced to 0°C. After stirring at 0°C overnight, the solid was collected by filtration and washed with a precooled (0°C) anhydrous ethanol solution (6 mL). The solid was recrystallized using anhydrous ethanol and then dried under reduced pressure at 45° C. to obtain a pure white solid product (4.47 g, yield 59%, dr>15:1). 1H NMR(500MHz,Chloroform-d)δ5.13(dd,J=15.1,8.6Hz,1H),5.01(dd,J=15.0,8.6Hz,1H),4.04(s,1H ),3.76(d,J=11.0Hz,1H),2.67(d,J=10.9Hz,1H),2.29(dd,J=13.1,4.2Hz,1H),2.08–1.87(m,5H),1 .81–1.61(m,6H),1.52(dd,J=11.0,5.5Hz,4H),1.44–1.32(m,3H),1.31–1.11(m,6H),1.02(d,J=6.7 Hz,3H),0.83(d,J=6.0Hz,3H),0.79(dd,J=9.4,6.6Hz,6H),0.75(s,3H),0.67(s,3H).HRMS(ESI),m / z for C 29 H 49 O3 + [M+H] + ,Calcd:445.3676,found445.3675.

[0039] Synthesis of (3aS,5S,6R,7aR,7bS,9aS,10R,12aS,12bS)-5,6-dihydroxy-7a,9a-dimethyl-10-((1S)-1-(3-((S)-2-methylpentan-3-yl)oxan-2-yl)ethyl)hexahydro-3H-benzo[c]indeno[5,4-e]oxirane-3-one (8):

[0040] 2,2,2-Trifluoroacetic anhydride (1.91 g, 9.1 mmol) was dissolved in chloroform (18 mL), cooled to 0 ° C, and 30% aqueous hydrogen peroxide solution (761 mg, 6.7 mmol) was added dropwise to the solution. The mixture was stirred at 0 ° C for 1 h, and then a solution of compound 4 (300 mg, 0.7 mmol) in chloroform (15 mL) was added dropwise, and the temperature of the reaction mixture was kept below 5 ° C. After addition, the reaction mixture was heated to room temperature and stirred for 4 h, then placed at 0 ° C for recooling, and freshly prepared peroxytrifluoroacetic acid (synthesized according to the above method) was added again. The reaction mixture was stirred at room temperature for 24 h. After the reaction was completed, sodium thiosulfate pentahydrate was added to quench the hydrogen peroxide solution in the reaction. When the starch potassium iodide test paper detected no oxidation, saturated sodium carbonate and saturated sodium bicarbonate were added for washing, extracted with dichloromethane, and the organic phases were combined and concentrated to dryness. The obtained crude product was subjected to silica gel column chromatography (PE / EA1 / 1) to obtain the product (200 mg, yield 63%). 1H NMR(500MHz,Chloroform-d)δ4.09(s,2H),4.01(s,1H),3.70(d,J=10.6Hz,1H),3.11(d,J=12 .1Hz,1H),2.73(d,J=5.4Hz,1H),2.49(s,2H),2.38–2.24(m,1H),2.13(ddd,J=14.9,12.2,2.4 Hz,1H),2.03–1.91(m,3H),1.86(dd,J=13.1,5.1Hz,2H),1.7–1.62(m,5H),1.55(s,2H),1.46 –1.36(m,2H),1.32(s,2H),1.26(d,J=15.0Hz,4H),1.06–0.84(m,15H),0.69(d,J=5.6Hz,3H).

[0041] Synthesis of (3aS,5S,6R,7aR,7bS,9aS,10R,12aS,12bS)-7a,9a-dimethyl-1-((2R,3R)-3-((S)-2-methylpentan-3-yl)oxiran-2-yl)ethyl)-3-oxohexadecahydro-1H-benzo[c]indeno[5,4-e]oxolane-5,6-diylbis(2-(naphthalen-1-yl)acetate) (1, compound BR04):

[0042] Compound 8 (152 mg, 0.3 mmol) was dissolved in dichloromethane (4 mL), and 2-naphthylacetic acid (118 mg, 0.6 mmol), dicyclohexylcarbodiimide (198 mg, 1.0 mmol) and catalyst 4-dimethylaminopyridine (2.0 mg, 0.004 mmol) were added. The reactants were then stirred at 0 ° C for 4 h. The reaction solution was filtered to remove most of the by-products of dicyclohexylcarbodiimide, the mother liquor was dried, and the crude product was purified by silica gel column chromatography to obtain a white solid product (135 mg, yield 52%). 1H NMR (500MHz, CDCl3) δ7.94 (dd, J=14.0, 8.0Hz, 2H), 7.87 (d, J=8.2Hz, 1H), 7. 81(d,J=8.1Hz,1H),7.74(d,J=8.1Hz,1H),7.56(m,J=25.9,15.5,7.8Hz,4H), 7.48–7.41(m,2H),7.34(dd,J=37.7,6.5Hz,1H),7.30(d,J=7.3Hz,1H)7.16(s ,1H),5.16(s,1H),4.66(d,J=10.2Hz,1H),4.03(d,J=3.0Hz,2H),3.95–3.67( m,4H),2.92(d,J=3.4Hz,1H),2.77(d,J=7.4Hz,1H),2.59(dd,J=13.2,5.3Hz, 2H),2.12–1.99(m,1H),1.96–1.82(m,3H),1.72–1.57(m,3H),1.43(s,3H),1. 39–1.32(m,3H),1.29–1.20(m,3H),1.08–1.01(m,7H),0.98(dd,J=17.6,8.3H z,8H),0.86(t,J=6.8Hz,1H),0.66(s,3H),0.57(d,J=6.7Hz,3H).MS(ESI)m / z 813.58[M+H] + ,835.59[M+Na] + .

[0043] Synthesis of (3aS,5S,6R,7aR,7bS,9aS,10R,12aS,12bS)-10-((2S,5S)-5-ethyl-3,4-dihydroxy-6-methylheptane-2-yl)-7a,9a-dimethyl-3-oxohexadecahydro-1H-benzo[c]indeno[5,4-e]oxol-5,6-diylbis(2-(naphthalen-1-yl)acetate) (2, Compound BR03):

[0044] Compound BR04 (106.0 mg, 0.1 mmol) was dissolved in a mixed solvent of 1,4-dioxane and water (v / v 1.0 mL / 0.5 mL), and concentrated sulfuric acid (13.1 mg, 0.13 mmol) was added dropwise, stirred at 60°C, and reacted overnight. After the reaction was completed, saturated sodium bicarbonate solution was added to adjust the pH to 8, extracted with ethyl acetate, and the organic phases were combined and dried over anhydrous sodium sulfate, and purified by silica gel column chromatography (PE / EA1 / 1) to obtain the target product (29 mg, yield 28%). 1H NMR(500MHz,Chloroform-d)δ7.93(s,2H),7.87(d,J=7.5Hz,1H),7.81(d,J=5.0Hz,1H),7.73(d,J=7.1Hz,1H),7.64–7.48(m,4H),7.43(s,2H),7.3 7(s,1H),7.30(s,1H),7.16(s,1H),5.16(s,1H),4.66(d,J=11.1Hz,1H), 4.12(d,J=7.0Hz,1H),4.02(s,2H),3.91(d,J=17.2Hz,1H),3.74(d,J=14. 6Hz,2H),2.97–2.88(m,1H),2.61(d,J=9.3Hz,1H),2.04(d,J=3.3Hz,2H) ,1.90(t,J=13.8Hz,2H),1.62(d,J=26.8Hz,5H),1.52–1.44(m,2H),1.44– 1.31(m,5H),1.27(d,J=11.8Hz,5H),1.13(dd,J=11.5,7.0Hz,3H),1.00( tt,J=21.0,8.6Hz,12H),0.66(s,3H),0.60(d,J=16.2Hz,3H).MS(ESI)m / z 831.55[M+H] + ,853.56[M+Na] + .

[0045] Example 2

[0046] This embodiment provides a long-acting brassinolide compound BR05. The preparation method refers to the synthesis process of BR04 in Example 1, and the difference from Example 1 is that the compound 2-naphthylacetic acid in Example 1 is replaced by an equimolar amount of isobutyric acid.

[0047] The characterization data are as follows:

[0048] 1H NMR(500MHz, CDCl3)δ5.37(d,J=8.7Hz,1H),4.92–4.83(m,1H,),4.17–3.98(m,2H),2.99(dd,J=12.3,4.4Hz,1H) ,2.73(dd,J=7.3,2.1Hz,1H),2.66–2.56(m,1H),2.53–2.41(m,2H),2.29(t,J=14.7Hz,1H),2.04–1.87(m,4H),1 .85–1.66(m,4H),1.66–1.56(m,2H),1.48–1.33(m,5H),1.32–1.23(m,4H),1.21(dd,J=10.7,7.0Hz,6H),1.12(d ,J=7.0Hz,6H),δ1.02–0.97(m,7H),0.96–0.92(m,6H).0.91(d,J=5.6Hz,3H),0.70(d,J=6.5Hz,3H).MS(ESI)m / z 617.54[M+H] + ,639.48[M+Na] + .

[0049]

[0050] Example 3

[0051] This embodiment provides a long-acting brassinolide compound BR01. The preparation method refers to the synthesis process of BR03 in Example 1, and the difference from Example 1 is that the compound 2-naphthylacetic acid in Example 1 is replaced by an equimolar amount of propionic acid.

[0052] The characterization data are as follows:

[0053] 1H NMR (500MHz, CDCl3) δ5.38 (s, 1H), 4.89 (dd, J = 8.3, 2.7Hz, 1H), 4.08 (dd, J = 41.8, 12.3, 9.8Hz, 2H), 3.59 (dd, J = 12.2, 5.2Hz,2H),2.99(dd,J=12.3,4.4Hz,1H),2.40–2.33(m,2H),2.33–2.20(m,3H),2.27–2.17(m,2H),2.16–2.01(m,2H), 1.96–1.86(m,2H),1.82–1.58(m,6H),1.49–1.32(m,4H),1.26(dd,J=10.9,4.3Hz,6H),1.17(t,J=7.5Hz,3H),1.10(t ,J=7.5Hz,3H),1.02(d,J=6.9Hz,3H),0.98(s,3H),0.97–0.92(m,6H),0.87(d,J=6.8Hz,3H),0.74(s,3H).MS(ESI)m / z 607.48[M+H] + ,629.45[M+Na] + .

[0054]

[0055] Example 4

[0056] This embodiment provides a long-acting brassinolide compound BR02. The preparation method refers to the synthesis process of BR03 in Example 1. The difference from Example 1 is that the compound 2-naphthylacetic acid in Example 1 is replaced by an equimolar amount of isobutyric acid.

[0057] The characterization data are as follows:

[0058] 1H NMR(500MHz,Chloroform-d)δ5.36(s,1H),4.90–4.85(m,1H),4.17–4.00(m,2H),3.62–3.53(m,2H),2.98(dd,J=12 .3,4.4Hz,1H),2.62–2.57(m,1H),2.45(d,J=7.0Hz,1H),2.33–2.24(m,1H),2.13–1.87(m,6H),1.83–1.55(m,6H), 1.49–1.40(m,2H),1.37(s,1H),1.33(s,1H),1.30–1.23(m,6H),1.20(dd,J=10.2,7.0Hz,6H),1.12(d,J=7.0Hz,6H ),1.02(d,J=6.8Hz,3H),0.99(s,3H),0.95(dd,J=9.9,7.2Hz,6H),0.87(d,J=6.8Hz,3H),0.74(s,3H).MS(ESI)m / z 635.39[M+H] + ,657.51[M+Na] + .

[0059]

[0060] Effect test:

[0061] The effects of the above compounds BR01-BR05 were tested, and the test method was as follows:

[0062] Sample treatment: The tea garden experiment was carried out in mid-July at the Yingde Base of the Tea Research Institute of Guangdong Academy of Agricultural Sciences (23°N, 113°E). Before treatment, the tea trees in the sample plots were fertilized, pest-free, covered with weed-proof cloth, and branches pruned. No pesticides, fungicides, or herbicides were applied during the entire treatment period, and tea leaves were not picked. Other management measures were consistent with field management. The concentration and dosage of the compound application were based on published literature and the effective dosage of commercial propionyl BR. The comprehensive analysis was 0.02 mg / L, per 667 m 2 The spray volume was 50 kg. The area of ​​each treatment group in this experiment was approximately 3 m 2, the compound application rate was 0.02 mg / L, and 250 mL was sprayed each time. The test sprayed the compound during the budding period of the tea trees, sprayed once on the 1st day (July 12), the 4th day (July 16) and the 7th day (July 19), a total of 3 sprays, and samples were collected on the 21st day (August 2) to detect tea-related indicators. The experiment set up 6 treatment groups and 2 control groups. The experimental group was 250 mL of water with 50 μL of the new BR compound (0.1 mg / mL, DMSO solubilized). The control group CK1 was 250 mL of water with 50 μL of DMSO (final concentration of 0.02%), and the control group CK2 was 250 mL of water with 50 μL of BR (brassinolide, 0.1 mg / mL, DMSO solubilized).

[0063] Bud density: The survey was conducted on the 21st day after the first spraying. Five square feet (33 cm × 33 cm, 0.1 m 2 ), investigate the germination density of tea trees.

[0064] 100 bud weight: Tea branches were picked from the sample plot on the 21st day after the first spraying. Five points were randomly selected from each treatment, each with a height of 33 cm × 33 cm (0.1 m 2 ). Prune the branches into uniform one bud and three leaves according to the picking standard, and weigh them using an electronic balance. The formula for calculating the weight of 100 buds of tea is as follows:

[0065]

[0066] Fresh leaf yield: Estimate tea yield (fresh weight) based on the 100 bud weight and germination density counted on the 21st day, and then estimate dry weight yield based on the moisture content of the tea leaves. The calculation formula is as follows:

[0067]

[0068] 21 days after exogenous application of propionyl brassinolide, the yield of fresh tea leaves was counted. The fresh leaf yield was estimated based on the bud density and 100 bud weight in the sample plot. Data are expressed as mean ± standard deviation (n = 5). T1: BR01 compound treatment; T2: BR02 compound treatment; T3: BR03 compound treatment; T4: BR04 compound treatment; T5: BR05 compound treatment; T6: propionyl BR (from Tian J, Lin Y, Han J, et al. Practical synthesis of epocholeone, a plant growth-promoting steroid with long-lasting activity [J]. Tetrahedron Letters, 2024, 140. DOI: 10.1016 / j.tetlet.2024.155024, Epocholeone) treatment; CK1: 0.02% DMSO treatment; CK2: BR treatment. The significant differences between the treatment group and the control group (CK1) were calculated using Student's T test and are indicated by *p<0.05 and **p<0.01. The results are as follows:

[0069] Table 1. Effects of exogenous application of propionyl brassinolide on tea yield

[0070]

[0071] Table 2. Changes in the content of non-ester catechin compounds in tea leaves after exogenous application of propionyl brassinolide

[0072]

[0073] From the above results, it can be found that the long-acting brassinolide compounds provided by the present invention can effectively increase the yield of fresh tea leaves and the catechin content of the product compared with other reagents, and have excellent technical effects.

[0074] The applicant declares that the present invention illustrates the long-acting brassinolide compounds and their applications through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0075] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0076] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A long-acting brassinolide compound, characterized in that: The structure of the long-acting brassinolide compound is shown in Formula I or Formula II: Wherein, R is selected from any one of substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alkynyl, substituted or unsubstituted C6-C12 aryl, and substituted or unsubstituted C6-C12 heteroaryl.

2. The long-acting brassinolide compound according to claim 1, characterized in that: The substituted group is selected from any one of halogen, hydroxyl, amino, nitro, thiol, aldehyde, ester, acyl, C1-C6 alkyl, C2-C6 alkenyl or C2-C6 alkynyl.

3. The long-acting brassinolide compound according to claim 2, characterized in that: The substituted group is selected from any one of halogen, hydroxyl, amino, nitro, thiol, aldehyde, ester, acyl, and C1-C6 alkyl.

4. The long-acting brassinolide compound according to any one of claims 1 to 3, characterized in that: The R is selected from any one of a substituted or unsubstituted C1-C12 alkyl group and a substituted or unsubstituted C6-C12 aryl group.

5. The long-acting brassinolide compound according to any one of claims 1 to 4, characterized in that: The R is selected from any one of substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted isopropyl, substituted or unsubstituted phenyl, and substituted or unsubstituted naphthyl.

6. The long-acting brassinolide compound according to any one of claims 1 to 5, characterized in that: The long-acting brassinolide compound is selected from any one of the compounds with the following structures:

7. Use of the long-acting brassinolide compound according to any one of claims 1 to 6 in the preparation of a plant growth regulator.

8. Use of the long-acting brassinolide compound according to any one of claims 1 to 6 in tea production.

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