PLANT GROWTH REGULATOR COMPOUNDS

Abstract

Compounds of formula (I) wherein the substituents are as defined in claim 1, useful as plant growth regulators and/or seed germination promoters.

##STR00001##

Claims

1. A compound of formula (I): ##STR00086## wherein R.sup.1 is cyano, C.sub.1-C.sub.6alkoxycarbonyl, N-C.sub.1-C.sub.6alkylaminocarbonyl, N,N-di(C.sub.1-C.sub.6alkyl)aminocarbonyl, C.sub.1-C.sub.6alkylsulfonyl, or aminocarbonyl; R.sup.2 is hydrogen or C.sub.1-C.sub.6alkyl; R.sup.3 is hydrogen, cyano, C.sub.1-C.sub.6alkyl, C.sub.1-C.sub.6alkoxy, or C.sub.1-C.sub.6haloalkyl; R.sup.4 and R.sup.5 are each independently selected from hydrogen, halogen, cyano, C.sub.1-C.sub.6alkyl, C.sub.1-C.sub.6alkoxy, C.sub.1-C.sub.6haloalkyl, C.sub.1-C.sub.6alkylsulfanyl, and C.sub.3-C.sub.6cycloalkyl; or R.sup.4 and R.sup.5 together with the carbon atoms to which they are attached, form a 5- or 6-membered saturated, partially saturated, or unsaturated cycloalkyl ring; Z is Z.sup.1, Z.sup.2, Z.sup.3, Z.sup.4, Z.sup.5, or Z.sup.6: ##STR00087## wherein Y.sup.1 and Y.sup.2 are each independently N or CR.sup.6; Y.sup.3 is O, S, C(R.sup.7)(R.sup.8) or C═O; Y.sup.4 is C(R.sup.7)(R.sup.8) or C═O; X.sup.1, X.sup.2, X.sup.3, and X.sup.4 are each independently N or CR.sup.9; R.sup.6 is hydrogen, halogen, cyano, C.sub.1-C.sub.3alkyl, or C.sub.1-C.sub.3alkoxy; R.sup.7 and R.sup.8 are each independently selected from hydrogen, halogen, C.sub.1-C.sub.3alkyl, C.sub.1-C.sub.3alkoxy, and C.sub.1-C.sub.3haloalkyl; or R.sup.7 and R.sup.8 together with the carbon atom to which they are attached may form a 3- to 6-membered cycloalkyl ring; R.sup.9 is hydrogen, halogen, cyano, hydroxy, amino, C.sub.1-C.sub.3alkyl, C.sub.1-C.sub.3haloalkyl, N-C.sub.1-C.sub.3alkylamino, N,N-di(C.sub.1-C.sub.3alkyl)amino, C.sub.1-C.sub.3alkylsulfanyl, or phenyl; R.sup.10 and R.sup.11 are each independently selected from hydrogen, halogen, C.sub.1-C.sub.3alkyl, C.sub.1-C.sub.3alkoxy, and C.sub.1-C.sub.3haloalkyl; or a salt or an N-oxide thereof.

2. The compound according to claim 1, wherein R.sup.1 is cyano, ethoxycarbonyl, N-methylaminocarbonyl, or N,N-di(methyl)carbonyl.

3. The compound according to claim 1, wherein R.sup.2 and R.sup.3 are both hydrogen.

4. The compound according to claim 1, wherein R.sup.4 and R.sup.5 are each independently selected from hydrogen, C.sub.1-C.sub.3alkyl, and C.sub.1-C.sub.3alkoxy.

5. The compound according to claim 1, wherein R.sup.4 is hydrogen, C.sub.1-C.sub.3alkyl, or C.sub.1-C.sub.3alkoxy, and R.sup.5 is methyl.

6. The compound according to claim 1, wherein R.sup.6 is hydrogen, fluorine, cyano, or C.sub.1-C.sub.3alkyl.

7. The compound according to claim 1, wherein R.sup.7 and R.sup.8 are each independently selected from hydrogen, methyl, methoxy and trifluoromethyl.

8. The compound according to claim 1, wherein R.sup.7 and R.sup.8 together with the carbon atom to which they are attached form a cyclopropyl or cyclobutyl ring.

9. The compound according to claim 1, wherein R.sup.9 is hydrogen, cyano, fluoro, bromo, trifluoromethyl, N,N-dimethylamino, or phenyl.

10. The compound according to claim 1, wherein R.sup.10 and R.sup.11 are each independently selected from hydrogen and C.sub.1-C.sub.3alkyl.

11. A plant growth regulating or seed germination promoting composition, comprising the compound according to claim 1, and an agriculturally acceptable formulation adjuvant.

12. A method for regulating the growth of plants at a locus, said method comprising applying to the locus a compound according to claim 1.

13. A method for promoting the germination of seeds, comprising applying to the seeds, or a locus containing the seeds, the compound according to claim 1.

14. Use of a compound of formula (I) according to claim 1 for promoting the germination of seeds and/or for regulating plant growth.

15. Use of a compound of formula (I) according to claim 1 for promoting the germination of seeds and/or for regulating plant growth.

Description

EXAMPLES

[0218] The Examples which follow serve to illustrate the invention.

Compound Synthesis and Characterisation

[0219] The following abbreviations are used throughout this section: DMF=N,N-dimethylformamide; M=molar; DME=1,2-dimethoxyethane; THF=tetrahydrofuran; M.p.=melting point; r.t.=room temperature; R.sub.t=retention time; MH.sup.+=molecular cation (i.e., measured molecular weight).

[0220] Throughout this description, temperatures are given in degrees Celsius (° C.) and “m.p.” means melting point. LC/MS means Liquid Chromatography Mass Spectrometry and the description of the apparatus and the following HPLC-MS methods were used for the analysis of the compounds:

[0221] Method A: Spectra were recorded on a ZQ Mass Spectrometer from Waters (Single quadrupole mass spectrometer) equipped with an electrospray source (Polarity: positive or negative ions, Capillary: 3.00 kV, Cone: 30.00 V, Extractor: 2.00 V, Source Temperature: 100° C., Desolvation Temperature: 250° C., Cone Gas Flow: 50 L/Hr, Desolvation Gas Flow: 400 L/Hr, Mass range: 100 to 900 Da) and an Acquity UPLC from Waters (Solvent degasser, binary pump, heated column compartment and diode-array detector. Column: Waters UPLC HSS T3, 1.8 μm, 30×2.1 mm, Temp: 60° C., flow rate 0.85 mL/min; DAD Wavelength range (nm): 210 to 500) Solvent Gradient: A=H.sub.2O+5% MeOH+0.05% HCOOH, B=Acetonitrile+0.05% HCOOH) gradient: 0 min 10% B; 0-1.2 min 100% B; 1.2-1.50 min 100% B.

[0222] Example 1: This example illustrates the preparation of ethyl (E) and/or (Z)-2-(2,3-dimethylindol-1-yl)-3-[(3,4-dimethyl-5-oxo-2H-furan-2-yl)oxy]prop-2-enoate (Compound I-30)

##STR00012##

[0223] To a solution of 2,3-dimethylindole (13.6 mmol, 2.00 g) in N,N-dimethylformamide (14 mL) was added potassium tert-butoxide (16.4 mmol, 1.93 g) under argon. After stirring for 5 minutes, ethyl bromoacetate (20.5 mmol, 2.31 mL) was added dropwise and the reaction mixture was stirred overnight at room temperature. The reaction mixture was poured on water and extracted with ethyl acetate. The combined organic layers were washed with 10% aqueous lithium chloride solution, then brine, dried over sodium sulfate, filtered and concentrated under reduced pressure. Purification of the crude material by flash chromatography over silica gel (ethyl acetate in cyclohexane) afforded compound of formula IV-29 in 88% yield (12.0 mmol, 2.77 g). LCMS (Method A): R.sub.t 1.08 min; ES.sup.+ 232 (M+H.sup.+).

##STR00013##

[0224] Compound of formula IV-29 (prepared as described above, 12.0 mmol, 2.77 g) was dissolved in Bredereck's reagent (35.9 mmol, 8.23 mL). The reaction mixture was heated up to 130° C. and stirred for 30 minutes. After cooling down to room temperature, the reaction mixture was diluted with brine and extracted with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure affording compound IIa-29. Compound of formula IIa-29 was then dissolved in tetrahydrofuran (49 mL) and aqueous hydrochloric acid solution (2M, 29.1 mL) was added. The reaction mixture was stirred at room temperature for 1 hour. Then aqueous hydrochloric acid solution (2M, 29.1 mL) was added again and it was stirred for 3 additional days. The reaction mixture was diluted with brine and extracted with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure. Purification of the crude material by flash chromatography over silica gel (ethyl acetate in cyclohexane) afforded compound of formula IIa-29 in 41% yield (5.90 mmol, 1.53 g). LCMS (Method A): R.sub.t 0.99 min; ES.sup.+ 260 (M+H.sup.+).

##STR00014##

[0225] Compound of formula II-29 (prepared as described above, 2.89 mmol, 0.750 g) was suspended in 1,2-dimethoxyethane (9.6 mL) and potassium tert-butoxide (3.47 mmol, 0.402 g) was added. After stirring for 5 minutes, a solution of 2-chloro-3,4-dimethyl-2H-furan-5-one (4.34 mmol, 0.636 g) in 1,2-dimethoxyethane (2 mL) was added dropwise. The reaction mixture was stirred overnight at room temperature. The reaction mixture was diluted with saturated aqueous solution of ammonium chloride and brine. It was then extracted with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure. Purification of the crude material by flash chromatography over silica gel (ethyl acetate in cyclohexane) afforded compound of formula I-30 in 52% yield (1.52 mmol, 0.560 g). LCMS (Method A): R.sub.t 1.12 min; ES.sup.+ 370 (M+H.sup.+).

[0226] 2-chloro-3,4-dimethyl-2H-furan-5-one can be prepared by a person skilled in the art using as reported in the literature (see “Design of photoaffinity labeling probes derived from 3,4,5-trimethylfuran-2(5H)-one for mode of action elucidation”, Tetrahedron (2016), 72, 3809-3817).

[0227] Example 2: This example illustrates the preparation of (E) and/or (Z)-2-indazol-1-yl-3-[(4-methyl-5-oxo-2H-furan-2-yl)oxy]prop-2-enenitrile (Compound I-43)

##STR00015##

[0228] To a solution of 1H-indazole (16.6 mmol, 2.00 g) in N,N-dimethylformamide (17 mL) was added potassium tert-butoxide (19.9 mmol, 2.35 g) under argon. After stirring for 5 minutes, bromoacetonitrile (24.9 mmol, 1.79 mL) was added dropwise and the reaction mixture was stirred overnight at room temperature. The reaction mixture was poured on water and extracted with ethyl acetate. The combined organic layers were washed with 10% aqueous lithium chloride solution, then brine, dried over sodium sulfate, filtered and concentrated under reduced pressure. Purification of the crude material by flash chromatography over silica gel (ethyl acetate in cyclohexane) afforded compound of formula IV-43 in 88% yield (13.0 mmol, 2.04 g). LCMS (Method A): R.sub.t 0.73 min; ES.sup.+ 158 (M+H.sup.+).

##STR00016##

[0229] Compound of formula IV-43 (prepared as described above, 5.27 mmol, 0.828 g) was dissolved in Bredereck's reagent (15.8 mmol, 3.63 mL). The reaction mixture was heated up to 130° C. and stirred for 15 minutes. After cooling down to room temperature, the reaction mixture was diluted with brine and extracted with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure affording compound IIa-43. Compound of formula IIa-43 was then dissolved in tetrahydrofuran (21 mL) and aqueous hydrochloric acid solution (2M, 10.5 mL) was added. The reaction mixture was stirred at room temperature overnight. The reaction mixture was diluted with brine and extracted with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure. Purification of the crude material by flash chromatography over silica gel (ethyl acetate in cyclohexane) afforded compound of formula II-43 in 89% yield (4.69 mmol, 0.870 g). LCMS (Method A): R.sub.t 0.74 min; ES.sup.+ 186 (M+H.sup.+).

##STR00017##

[0230] Compound of formula II-43 (prepared as described above, 2.35 mmol, 0.435 g) was dissolved in 1,2-dimethoxyethane (12 mL) and potassium tert-butoxide (2.82 mmol, 0.333 g) was added. After stirring for 5 minutes, a solution of 2-chloro-4-methyl-2H-furan-5-one (3.52 mmol, 0.467 g) in 1,2-dimethoxyethane (2 mL) was added dropwise. The reaction mixture was stirred for 3 days at room temperature. The reaction mixture was diluted with saturated aqueous solution of ammonium chloride and brine. It was then extracted with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure. Purification of the crude material by flash chromatography over silica gel (ethyl acetate in cyclohexane) afforded compound of formula I-43 in 35% yield (0.811 mmol, 0.228 g). LCMS (Method A): R.sub.t 0.89 min; ES.sup.+ 282 (M+H.sup.+).

[0231] Example 3: This example illustrates the preparation of (E) and/or (Z)-2-(3-cyanoindol-1-yl)-N-methyl-3-[(4-methyl-5-oxo-2H-furan-2-yl)oxy]prop-2-enamide (Compound I-82)

##STR00018##

[0232] To a solution of 3-cyanoindole (13.8 mmol, 2.00 g) in N,N-dimethylformamide (14 mL) was added potassium tert-butoxide (16.6 mmol, 1.95 g) under argon. After stirring for 5 minutes, 2-chloro-N-methylacetamide (20.7 mmol, 2.29 g) was added dropwise and the reaction mixture was stirred for 30 minutes at room temperature. The reaction mixture was poured on water and a precipitate was formed. It was filtered, washed with water and dried under reduced pressure to afford compound of formula IV-82 (13.8 mmol, 3.28 g). The resulting crude was used without further purification. LCMS (Method A): R.sub.t 0.59 min: ES.sup.+ 214 (M+H.sup.+).

##STR00019##

[0233] Compound of formula IV-82 (prepared as described above, 4.69 mmol, 1.00 g) was dissolved in toluene (9.4 mL) and Bredereck's reagent (14.1 mmol, 3.23 mL) was added. The reaction mixture was heated up to 130° C. and stirred for 30 minutes. After cooling down to room temperature, the reaction mixture was diluted with brine and extracted with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure affording compound IIa-82. Compound of formula IIa-82 was then dissolved in tetrahydrofuran (21 mL) and aqueous hydrochloric acid solution (2M, 10.3 mL) was added. The reaction mixture was stirred at room temperature for 20 minutes. The reaction mixture was diluted with brine and extracted with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure. Purification of the crude material by flash chromatography over silica gel (ethyl acetate in cyclohexane) afforded compound of formula II-82 in 61% yield (3.14 mmol, 0.758 g). LCMS (Method A): R.sub.t 0.63-0.85 min; ES.sup.+ 242 (M+H.sup.+).

##STR00020##

[0234] Compound of formula II-82 (prepared as described above, 1.57 mmol, 0.379 g) was dissolved in 1,2-dimethoxyethane (7.9 mL) and potassium tert-butoxide (1.89 mmol, 0.223 g) was added. After stirring for 5 minutes, a solution of 2-chloro-4-methyl-2H-furan-5-one (2.36 mmol, 0.312 g) in 1,2-dimethoxyethane (2 mL) was added dropwise. The reaction mixture was stirred overnight at room temperature. The reaction mixture was diluted with saturated aqueous solution of ammonium chloride and brine. It was then extracted with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure. Purification of the crude material by flash chromatography over silica gel (ethyl acetate in cyclohexane) afforded compound of formula I-82 in 35% yield (0.811 mmol, 0.228 g). LCMS (Method A): R.sub.t 0.83 min; ES.sup.+ 338 (M+H.sup.+).

TABLE-US-00010 TABLE 2 LC/MS data (R.sub.t = Retention time) for selected compounds of formula (I) No. Compound Name Structure LC/MS I-47-Z (Z)-3-[(3,4-dimethyl-5- oxo-2H-furan-2-yl)oxy]-2- indazol-1-yl-prop-2- enenitrile [00021] R.sub.t = 0.96 min; ES+ 296 (M + H.sup.+) I-35-Z ethyl (Z)-2-(benzotriazol- 1-yl)-3-[(3,4-dimethyl-5- oxo-2H-furan-2- yl)oxy]prop-2-enoate [00022] R.sub.t = 0.88 min; ES+ 344 (M + H.sup.+) I-31-Z ethyl (Z)-2-(benzotriazol- 1-yl)-3-[(4-methyl-5-oxo- 2H-furan-2-yl)oxy]prop-2- enoate [00023] R.sub.t = 0.85 min; ES+ 330 (M + H.sup.+) I-1-Z ethyl (Z)-2-indol-1-yl-3- [(4-methyl-5-oxo-2H- furan-2-yl)oxy]prop-2- enoate [00024] R.sub.t = 0.99 min; ES+ 328 (M + H.sup.+) I-47-E (E)-3-[(3,4-dimethyl-5- oxo-2H-furan-2-yl)oxy]-2- indazol-1-yl-prop-2- enenitrile [00025] R.sub.t = 0.93 min; ES+ 296 (M + H.sup.+) I-26-Z ethyl (Z)-2-(3-cyanoindol- 1-yl)-3-[(3,4-dimethyl-5- oxo-2H-furan-2- yl)oxy]prop-2-enoate [00026] R.sub.t = 0.99 min; ES+ 367 (M + H.sup.+) I-7-Z ethyl (Z)-3-[(3,4-dimethyl- 5-oxo-2H-furan-2-yl)oxy]- 2-indol-1-yl-prop-2- enoate [00027] R.sub.t = 1.04 min; ES+ 342 (M + H.sup.+) I-2-Z ethyl (Z)-3-[(4-methyl-5- oxo-2H-furan-2-yl)oxy]-2- [5-(trifluoromethyl)indol-1- yl]prop-2-enoate [00028] R.sub.t = 1.11 min; ES+ 396 (M + H.sup.+) I-3-Z ethyl (Z)-2-(5-fluoroindol- 1-yl)-3-[(4-methyl-5-oxo- 2H-furan-2-yl)oxy]prop-2- enoate [00029] R.sub.t = 1.03 min; ES+ 346 (M + H.sup.+) I-46-Z ethyl (Z)-3-[(3,4-dimethyl- 5-oxo-2H-furan-2-yl)oxy]- 2-indazol-1-yl-prop-2- enoate [00030] R.sub.t = 0.92 min; ES+ 343 (M + H.sup.+) I-9-Z ethyl (Z)-3-[(3,4-dimethyl- 5-oxo-2H-furan-2-yl)oxy]- 2-(5-fluoroindol-1-yl)prop- 2-enoate [00031] R.sub.t = 1.06 min; ES+ 360 (M + H.sup.+) I-51-Z ethyl (Z)-3-[(3,4-dimethyl- 5-oxo-2H-furan-2-yl)oxy]- 2-(3-fluoroindazol-1- yl)prop-2-enoate [00032] R.sub.t = 1.03 min; ES+ 361 (M + H.sup.+) I-50-Z ethyl (Z)-2-(3- fluoroindazol-1-yl)-3-[(4- methyl-5-oxo-2H-furan-2- yl)oxy]prop-2-enoate [00033] R.sub.t = 0.99 min; ES+ 347 (M + H.sup.+) I-43-Z (Z)-2-indazol-1-yl-3-[(4- methyl-5-oxo-2H-furan-2- yl)oxy]prop-2-enenitrile [00034] R.sub.t = 0.89 min; ES+ 282 (M + H.sup.+) I-8-Z ethyl (Z)-3-[(3,4-dimethyl- 5-oxo-2H-furan-2-yl)oxy]- 2-[5-(trifluoromethyl)indol- 1-yl]prop-2-enoate [00035] R.sub.t = 1.14 min; ES+ 410 (M + H.sup.+) I-30-Z ethyl (Z)-2-(2,3- dimethylindol-1-yl)-3- [(3,4-dimethyl-5-oxo-2H- furan-2-yl)oxy]prop-2- enoate [00036] R.sub.t = 1.12 min; ES+ 370 (M + H.sup.+) I-5-Z ethyl (Z)-3-[(4-methyl-5- oxo-2H-furan-2-yl)oxy]-2- (5-phenylindol-1-yl)prop- 2-enoate [00037] R.sub.t = 1.12 min; ES+ 404 (M + H.sup.+) I-29-Z ethyl (Z)-2-(2,3- dimethylindol-1-yl)-3-[(4- methyl-5-oxo-2H-furan-2- yl)oxy]prop-2-enoate [00038] R.sub.t = 1.09 min; ES+ 356 (M + H.sup.+) I-25-Z ethyl (Z)-2-(3-cyanoindol- 1-yl)-3-[(4-methyl-5-oxo- 2H-furan-2-yl)oxy]prop-2- enoate [00039] R.sub.t = 0.95 min; ES+ 353 (M + H.sup.+) I-60-Z ethyl (Z)-2-[6- (dimethylamino)-2-fluoro- purin-9-yl]-3-[(4-methyl-5- oxo-2H-furan-2- yl)oxy]prop-2-enoate [00040] R.sub.t = 0.88 min; ES+ 392 (M + H.sup.+) I-28-Z ethyl (Z)-3-[(3,4-dimethyl- 5-oxo-2H-furan-2-yl)oxy]- 2-(3-methylindol-1- yl)prop-2-enoate [00041] R.sub.t = 1.09 min; ES+ 356 (M + H.sup.+) I-42-Z ethyl (Z)-2-indazol-1-yl-3- [(4-methyl-5-oxo-2H- furan-2-yl)oxy]prop-2- enoate [00042] R.sub.t = 0.88 min; ES+ 329 (M + H.sup.+) I-34-Z (Z)-2-(benzotriazol-1-yl)- N,N-dimethyl-3-[(4- methyl-5-oxo-2H-furan-2- yl)oxy]prop-2-enamide [00043] R.sub.t = 0.76 min; ES+ 329 (M + H.sup.+) I-27-Z ethyl (Z)-2-(3- methylindol-1-yl)-3-[(4- methyl-5-oxo-2H-furan-2- yl)oxy]prop-2-enoate [00044] R.sub.t = 1.05 min; ES+ 342 (M + H.sup.+) I-88-Z ethyl (Z)-2-(3-cyanoindol- 1-yl)-3-[(3-methoxy-4- methyl-5-oxo-2H-furan-2- yl)oxy]prop-2-enoate [00045] R.sub.t = 1.00 min; ES+ 383 (M + H.sup.+) I-59-Z ethyl (Z)-3-[(3,4-dimethyl- 5-oxo-2H-furan-2-yl)oxy]- 2-(2-methylbenzimidazol- 1-yl)prop-2-enoate [00046] R.sub.t = 0.71 min; ES+ 357 (M + H.sup.+) I-80-Z ethyl (Z)-3-[(4-methyl-5- oxo-2H-furan-2-yl)oxy]-2- (3,4,5-trimethylpyrazol-1- yl)prop-2-enoate [00047] R.sub.t = 0.85 min; ES+ 321 (M + H.sup.+) I-61-Z ethyl (Z)-2-[6- (dimethylamino)-2-fluoro- purin-9-yl]-3-[(3,4- dimethyl-5-oxo-2H-furan- 2-yl)oxy]prop-2-enoate [00048] R.sub.t = 0.91 min; ES+ 406 (M + H.sup.+) I-86-Z (Z)-2-(3-cyanoindol-1-yl)- N,N-dimethyl-3-[(4- methyl-5-oxo-2H-furan-2- yl)oxy]prop-2-enamide [00049] R.sub.t = 0.86 min; ES+ 352 (M + H.sup.+) I-56-Z ethyl (Z)-2-(benzimidazol- 1-yl)-3-[(4-methyl-5-oxo- 2H-furan-2-yl)oxy]prop-2- enoate [00050] R.sub.t = 0.77 min; ES+ 329 (M + H.sup.+) I-82-Z (Z)-2-(3-cyanoindol-1-yl)- N-methyl-3-[(4-methyl-5- oxo-2H-furan-2- yl)oxy]prop-2-enamide [00051] R.sub.t = 0.83 min; ES+ 338 (M + H.sup.+) I-62-Z ethyl (Z)-3-[(4-methyl-5- oxo-2H-furan-2-yl)oxy]-2- pyrrolo[2,3-d]pyrimidin-7- yl-prop-2-enoate [00052] R.sub.t = 0.69 min; ES+ 330 (M + H.sup.+) I-37-Z (Z)-2-(benzotriazol-1-yl)- 3-[(3,4-dimethyl-5-oxo- 2H-furan-2-yl)oxy]-N- methyl-prop-2-enamide [00053] R.sub.t = 0.75 min; ES+ 329 (M + H.sup.+) I-83-Z (Z)-2-(3-cyanoindol-1-yl)- 3-[(3,4-dimethyl-5-oxo- 2H-furan-2-yl)oxy]-N- methyl-prop-2-enamide [00054] R.sub.t = 0.87 min; ES+ 352 (M + H.sup.+) I-81-Z ethyl (Z)-3-[(3,4-dimethyl- 5-oxo-2H-furan-2-yl)oxy]- 2-(3,4,5-trimethylpyrazol- 1-yl)prop-2-enoate [00055] R.sub.t = 0.89 min; ES+ 335 (M + H.sup.+) I-33-Z (Z)-2-(benzotriazol-1-yl)- N-methyl-3-[(4-methyl-5- oxo-2H-furan-2- yl)oxy]prop-2-enamide [00056] R.sub.t = 0.70 min; ES+ 315 (M + H.sup.+) I-58-Z ethyl (Z)-2-(2- methylbenzimidazol-1-yl)- 3-[(4-methyl-5-oxo-2H- furan-2-yl)oxy]prop-2- enoate [00057] R.sub.t = 0.67 min; ES+ 343 (M + H.sup.+) I-57-Z ethyl (Z)-2-(benzimidazol- 1-yl)-3-[(3,4-dimethyl-5- oxo-2H-furan-2- yl)oxy]prop-2-enoate [00058] R.sub.t = 0.81 min; ES+ 343 (M + H.sup.+) I-48-E (E)-3-[(3,4-dimethyl-5- oxo-2H-furan-2-yl)oxy]-2- indazol-1-yl-N-methyl- prop-2-enamide [00059] R.sub.t = 0.81 min; ES+ 328 (M + H.sup.+) I-33-E (E)-2-(benzotriazol-1-yl)- N-methyl-3-[(4-methyl-5- oxo-2H-furan-2- yl)oxy]prop-2-enamide [00060] R.sub.t = 0.71 min; ES+ 315 (M + H.sup.+) I-89-Z ethyl (Z)-3-[(4-methyl-5- oxo-2H-furan-2-yl)oxy]-2- pyrrolo[2,3-b]pyrazin-5-yl- prop-2-enoate [00061] R.sub.t = 0.78 min; ES+ 344 (M + H.sup.+) I-90-Z ethyl (Z)-3-[(3,4-dimethyl- 5-oxo-2H-furan-2-yl)oxy]- 2-pyrrolo[2,3-b]pyrazin-5- yl-prop-2-enoate [00062] R.sub.t = 0.82 min; ES+ 344 (M + H.sup.+) I-38-Z (Z)-2-(benzotriazol-1-yl)- 3-[(3,4-dimethyl-5-oxo- 2H-furan-2-yl)oxy]-N,N- dimethyl-prop-2-enamide [00063] R.sub.t = 0.80 min; ES+ 343 (M + H.sup.+) I-11-Z ethyl (Z)-3-[(3,4-dimethyl- 5-oxo-2H-furan-2-yl)oxy]- 2-(5-phenylindol-1- yl)prop-2-enoate [00064] R.sub.t = 1.15 min; ES+ 418 (M + H.sup.+) I-76-Z ethyl (Z)-3-[(4-methyl-5- oxo-2H-furan-2-yl)oxy]-2- (4-oxo-1-quinolyl)prop-2- enoate [00065] R.sub.t = 0.78 min; ES+ 356 (M + H.sup.+) I-87-Z (Z)-2-(3-cyanoindol-1-yl)- 3-[(3,4-dimethyl-5-oxo- 2H-furan-2-yl)oxy]-N,N- dimethyl-prop-2-enamide [00066] R.sub.t = 0.91 min; ES+ 366 (M + H.sup.+) I-44-Z (Z)-2-indazol-1-yl-N- methyl-3-[(4-methyl-5- oxo-2H-furan-2- yl)oxy]prop-2-enamide [00067] R.sub.t = 0.76 min; ES+ 314 (M + H.sup.+) I-45-Z (Z)-2-indazol-1-yl-N,N- dimethyl-3-[(4-methyl-5- oxo-2H-furan-2- yl)oxy]prop-2-enamide [00068] R.sub.t = 0.81 min; ES+ 328 (M + H.sup.+) I-49-Z (Z)-3-[(3,4-dimethyl-5- oxo-2H-furan-2-yl)oxy]-2- indazol-1-yl-N,N- dimethyl-prop-2-enamide [00069] R.sub.t = 0.85 min; ES+ 342 (M + H.sup.+) I-63-Z ethyl (Z)-3-[(3,4-dimethyl- 5-oxo-2H-furan-2-yl)oxy]- 2-pyrrolo[2,3-d]pyrimidin- 7-yl-prop-2-enoate [00070] R.sub.t = 0.75 min; ES+ 344 (M + H.sup.+) I-48-Z (Z)-3-[(3,4-dimethyl-5- oxo-2H-furan-2-yl)oxy]-2- indazol-1-yl-N-methyl- prop-2-enamide [00071] R.sub.t = 0.79 min; ES+ 328 (M + H.sup.+) I-69-Z ethyl (Z)-3-[(3,4-dimethyl- 5-oxo-2H-furan-2-yl)oxy]- 2-(2-oxo-1,3-benzoxazol- 3-yl)prop-2-enoate [00072] R.sub.t = 0.97 min; ES+ 390 (M + H.sup.+) I-73-Z ethyl (Z)-2-(5- bromoindolin-1-yl)-3- [(3,4-dimethyl-5-oxo-2H- furan-2-yl)oxy]prop-2- enoate [00073] R.sub.t = 1.10 min; ES+ 422 (M + H.sup.+) I-65-Z ethyl (Z)-3-[(3,4-dimethyl- (5-oxo-2H-furan-2-yl)oxy]- 2-(2-oxo-1,3- benzothiazol-3-yl)prop-2- enoate [00074] R.sub.t = 1.00 min; ES+ 376 (M + H.sup.+) I-72-Z ethyl (Z)-2-(5- bromoindolin-1-yl)-3-[(4- methyl-5-oxo-2H-furan-2- yl)oxy]prop-2-enoate [00075] R.sub.t = 1.08 min; ES+ 408 (M + H.sup.+) I-68-Z ethyl (Z)-3-[(4-methyl-5- oxo-2H-furan-2-yl)oxy]-2- (2-oxo-1,3-benzoxazol-3- yl)prop-2-enoate [00076] R.sub.t = 0.94 min; ES+ 346 (M + H.sup.+) I-64-Z ethyl (Z)-3-[(4-methyl-5- oxo-2H-furan-2-yl)oxy]-2- (2-oxo-1,3-benzothiazol- 3-yl)prop-2-enoate [00077] R.sub.t = 0.96 min; ES+ 362 (M + H.sup.+) I-78-Z ethyl (Z)-3-[(4-methyl-5- oxo-2H-furan-2-yl)oxy]-2- (3-oxo-1,4-benzothiazin- 4-yl)prop-2-enoate [00078] R.sub.t = 1.01 min; ES+ 376 (M + H.sup.+) I-70-Z ethyl (Z)-2-indolin-1-yl-3- [(4-methyl-5-oxo-2H- furan-2-yl)oxy]prop-2- enoate [00079] R.sub.t = 1.00 min; ES+ 330 (M + H.sup.+) I-79-Z ethyl (Z)-3-[(3,4-dimethyl- 5-oxo-2H-furan-2-yl)oxy]- 2-(3-oxo-1,4- benzothiazin-4-yl)prop-2- enoate [00080] R.sub.t = 1.05 min; ES+ 390 (M + H.sup.+) I-66-Z ethyl (Z)-3-[(4-methyl-5- oxo-2H-furan-2-yl)oxy]-2- (2′- oxospiro[cyclopropane- 1,3′-indoline]-1′-yl)prop-2- enoate [00081] R.sub.t = 0.94 min; ES+ 370 (M + H.sup.+) I-67-Z ethyl (Z)-3-[(3,4-dimethyl- 5-oxo-2H-furan-2-yl)oxy]- 2-(2′- oxospiro[cyclopropane- 1,3′-indoline]-1′-yl)prop-2- enoate [00082] R.sub.t = 0.97 min; ES+ 384 (M + H.sup.+) I-71-Z ethyl (Z)-3-[(3,4-dimethyl- 5-oxo-2H-furan-2-yl)oxy]- 2-indolin-1-yl-prop-2- enoate [00083] R.sub.t = 1.04 min; ES+ 344 (M + H.sup.+) I-74-Z ethyl (Z)-3-[(4-methyl-5- oxo-2H-furan-2-yl)oxy]-2- (2-oxo-3,4- dihydroquinolin-1-yl)prop- 2-enoate [00084] R.sub.t = 0.88 min; ES+ 358 (M + H.sup.+) I-75-Z ethyl (Z)-3-[(3,4-dimethyl- 5-oxo-2H-furan-2-yl)oxy]- 2-(2-oxo-3,4- dihydroquinolin-1-yl)prop- 2-enoate [00085] R.sub.t = 0.92 min; ES+ 372 (M + H.sup.+)

BIOLOGICAL EXAMPLES

Example B1: Dark Induced Senescence of Corn Leaf

[0235] It is known that strigolactones regulate (accelerate) leaf senescence, potentially through D14 receptor signaling.

[0236] Corn plants of variety Multitop were grown in a greenhouse with relative 75% humidity and at 23-25° C. for 6 weeks. 1.4 cm diameter leaf discs were placed into 24-well plates containing test compounds in a concentration gradient (100 μM-0.0001 μM) at a final concentration of 0.5% DMSO. Each concentration was tested in 12 replicates. Plates were sealed with seal foil. The foil was pierced to provide gas exchange in each well. The plates were placed into the completely dark climatic chamber. Plates were incubated in the chamber with 75% humidity and at 23° C. for 8 days. On days 0, 5, 6, 7 and 8 photographs were taken of each plate, and image analysis conducted with a macro developed using the ImageJ software. The image analysis was used to determine the concentration at which 50% senescence was achieved (IC.sub.50), see Table 3. The lower the value, the higher senescence induction potency.

[0237] The following compounds display an IC.sub.50 lower than 3 μM: I-47-Z, I-37-Z, I-33-E, I-83-Z, I-82-Z, I-47-E, I-43-Z, I-86-Z, I-34-Z, I-66-Z, I-67-Z, I-88-Z, I-64-Z, I-69-Z, I-68-Z, I-8-Z, I-2-Z, I-9-Z, I-3-Z, I-51-Z, I-50-Z, I-30-Z, I-29-Z, I-79-Z, I-78-Z, I-65-Z, I-46-Z, I-35-Z, I-31-Z, I-59-Z, I-25-Z, I-26-Z, I-80-Z, I-81-Z, I-42-Z, I-61-Z, I-60-Z, I-56-Z, I-57-Z, I-28-Z, I-27-Z, I-11-Z, I-5-Z, I-90-Z, I-62-Z, I-73-Z, I-72-Z, I-70-Z, I-7-Z, I-1-Z.

Example B2: Yoshimulactone Green (YLG) Displacement Assay

[0238] Yoshimulactone Green (YLG) is a fluorogenic agonist for the strigolactone receptor D14 and was used in competition assays to assess the binding affinity of test compounds as previously described with minor modifications (M. Yoshimura, A. Sato, K. Kuwata, Y. Inukai, T. Kinoshita, K. Itami, Y. Tsuchiya, S. Hagihara, ‘Discovery of shoot branching regulator targeting strigolactone receptor DWARF14’, ACS Cent. Sci. 2018, 4, 230-234). ZmD14 (1 μg) was incubated in the presence and absence of test compounds in buffer (PBS, 0.1% BSA) for 5 min at room temperature followed by the addition of YLG to 1 μM. The final reaction volume was 150 μL and all wells contained 1% DMSO. The extent of YLG hydrolysis by D14 was assessed by measuring the fluorescence intensity (excitation: 480 nm, emission: 520 nm) in a Mithras LB 940 plate reader (Berthold Technologies) at a single time-point during the linear phase of the reaction. The half-maximal inhibitory concentration (IC.sub.50) values were determined from the normalized fluorescence intensities relative to DMSO controls for test compounds over an 8-point dilution curve (30 μM top concentration, 3-fold dilution). The following compounds display an IC.sub.50 lower than 5 μM: I-47-Z, I-37-Z, I-33-E, I-83-Z, I-82-Z, I-47-E, I-43-Z, I-86-Z, I-34-Z, I-66-Z, I-67-Z, I-88-Z, I-64-Z, I-69-Z, I-68-Z, I-8-Z, I-2-Z, I-9-Z, I-3-Z, I-51-Z, I-50-Z, I-30-Z, I-29-Z, I-79-Z, I-78-Z, I-65-Z, I-46-Z, I-35-Z, I-31-Z, I-59-Z, I-25-Z, I-26-Z, I-80-Z, I-81-Z, I-42-Z, I-61-Z, I-60-Z, I-56-Z, I-57-Z, I-28-Z, I-27-Z, I-11-Z, I-5-Z, I-90-Z, I-62-Z, I-73-Z, I-72-Z, I-70-Z, I-7-Z, and I-1-Z.