1. β-carboline compound with a structure shown in one of the following formulae:

2. A method for preparing the β-carboline according to claim 1, regarding to Ia-5, Ia-8, and Ia-9, the method comprising the steps of: reacting β-carboline alkaloid harmol with isocyanate to obtain compound Ia-5, reacting β-carboline alkaloid harmol with acyl chloride to obtain compound Ia-8, and reacting β-carboline alkaloid harmol with amino acid in presence of a condensation agent to obtain compound Ia-9:

3. Use of a β-carboline compound according to claim 1 as bactericidal agent against cucumber Fusarium wilt on plants.

Field of the Invention

[0001]The present invention relates to β-carboline alkaloid derivatives, their preparation methods and use in the prevention and treatment of plant bacterial infections. The present invention relates to the technical field of pesticides.

Background of the Invention

[0002]The skeleton structures of β-carboline, dihydro-β-carboline and tetrahydro-β-carboline widely exist in natural products and drug molecules. Harmine and tetrahydroharmine belong to β-carboline and tetrahydro-β-carboline alkaloids respectively and are representative compounds of harmala alkaloids. Harmine was first separated from P. harmala L. This alkaloid shows cytotoxicity to leukemia cell lines HL60 and K562. Tetrahydroharmine is a fluorescent molecule separated from Malpighiacease plant Banisteriopsis caapi. This compound has weak inhibition to the re-uptake of 5-hydroxytryptamine. Harmaline is an agonist of the central nervous system and a reversible inhibitor of monoamine oxidase (MAO-A).

[0003]Currently, the research on β-carboline, dihydro-β-carboline and tetrahydro-β-carboline and substances similar to them focuses on anti-tumor, killing of human parasites and monoamine oxidase inhibitors. However, as far as we know, no document reports the activity of β-carboline, dihydro-β-carboline and tetrahydro-β-carboline and substances similar to them against plant viruses, and little was reported on their bactericidal activity and insecticidal activity. In the aspect of bactericidal activity: Fu Haibo et al from Gansu Agricultural University researched and found in 2007 that the extracting solutions of P. harmala L. in different solvents all have certain inhibiting effect to spore germination of four kinds of pathogenic bacteria, including Botrytis cinerea, Fusarium oxysporum, Alternaria solani and Cladosporium cucumerinum Ellis et Arthur, and their EC 50 is 0.060, 0.199, 0.105 and 0.223g/mL respectively (Fu Haibo, Ding Defang, Zhao Hongmei, Yang Shunyi, Grassland and Lawn, 2008, 1, 44-48.); in 2007, Wen Ren et al from Fudan University reported derivatives with a structure of 1-(3-indol)-1,2,3,4-tetrahydro-β-carboline and researched the in vitro activity of these derivatives against Pyricularia oryzae (CN101020688); in 2011, Zhang Yaomou et al from South China Agricultural University reported compounds with a structure of β-carboline-3-oxime ester and meanwhile studied the inhibitory activity of these compounds against Colletotrichum musae, Colletotrichum gloeosporioides and tomato late plight (Lu Shaoying, Zhang Yaomou, Synthetic Chemistry, 2011, 19 (6), 769-772.); in 2012, this research group again reported compounds with a structure of 1-p-trifluoromethylphenyl-β-carboline-3-carbonyl bishydrazide, but the quantity of the compounds was small and their bacteriostatic activity against Rhizoctorzia solani was tested only (Cai Ying, Huang Jianfeng, Zhang Meidan, Zeng Yong, Zhang Yaomo, Synthetic Chemistry, 2012, 20(6), 736-739.). In the aspect of insecticidal activity: in 2005, Zhao Xiaomeng et al from Beijing University of Agriculture reported the contact activity of the ethanol extract, chloroform extract and water extract of the overground part of P. harmala L. in the growing period against Myzus persicae, Macrosiphum rosivorum and Tetranychus cinnabarinus. The result is that their contact activity against spider mites is all above 95% at concentration of 10mg/mL, and that against two kinds of aphids is above 70% at concentration of 10mg/mL (Zhao Xiaomeng, Zeng Zhaohai, Chinese Agricultural Science Bulletin, 2005,21(4), 278-279.); in 2010, Zhong Guohua et al from South China Agricultural University reported the insecticidal activity of 1,3-disubstituted β-carboline and tetrahydro-β-carboline derivatives against culex pipiens larvae and Lipaphis erysimi. To be specific, the LC 50 of the compounds with a structure of 1-phenyl substituted β-carboline and tetrahydro-β-carboline-3-methyl ester against culex pipiens larvae is 20.82mg/Land 23.98mg/Lrespectively, and the LC 50 against Lipaphis erysimi is 53.16mg/L and 68.05mg/Lrespectively (Zeng, Y; Zhang, Y M.; Weng, Q. F.; Hu, M. Y; Zhong G. H. Molecules 2010, 15, 7775-7791.).

Summary of the Invention

[0004]The object of the present invention is to provide β-carboline alkaloid derivatives and their preparation methods and use in killing of bacteria on plants. The β-carboline, alkaloid derivatives described in the present invention show bactericidal activity on plants.

[0005]The β-carboline, dihydro-β-carboline and tetrahydro-β-carboline alkaloid derivatives described in the present disclosure are compounds with a structure shown in the following general formula (I):

[0006]The β-carboline alkaloid derivatives described in the present invention are compounds with a structure shown in one of the following formulas (I a -5, I a -8, I a -9):

[0007]The β-carboline alkaloid described in the present invention may be prepared by the following method (Path 4): Harmine is demethylated under acidic condition to obtain β-carboline alkaloid harmol. Path 4: The β-carboline alkaloid derivatives (I) described in the present invention may be prepared by the following method (Path 6): reacting Harmol with isocyanate to obtain compound I a -5, reacting Harmol with acyl chloride to obtain compound I a -8, and reacting Harmol with amino acid in presence of a condensation agent to obtain compound I a -9.

Path 6:

[0008]

[0009]In the above general formula (I), R represents hydrogen, 1 to 4 halogen atoms, 1 to 4 nitro groups, 1 to 4 cyano groups, 1 to 4 C1-C6 alkoxy groups, 1 to 4 hydroxy groups, 1 to 4 ester groups, 1 to 2 OCH 2 O, 1 to 2 OCH 2 CH 2 O, 1 to 4 C0-C10 amino groups, 1 to 4 C1-C6 alkyl carbonyl groups, 1 to 4 C1-C10 alkoxy carbonyl groups, 1 to 4 C1-C10 alkyl amino carbonyl groups, 1 to 4 C1-C6 alkoxy carbonyloxy groups, 1 to 4 C1-C6 alkyl amino carbonyloxy groups, 1 to 4 C1-C10 α-amino alkyl carbonyloxy groups:

R 1< respectively represents hydrogen, hydroxy, halogen atom, cyano group, ester group, amido group, C1-C10 hydrocarbyl, C1-C6 alkoxy, C1-C4 alkyl carbonyloxy, C1-C4 alkoxy carbonyloxy, C1-C10 nitrogen-containing heterocyclic ring, C1-C10 oxygen-containing heterocyclic ring, C1-C10 sulfur-containing heterocyclic ring, as well as stereomers of the foregoing compounds; R 2< respectively represents hydrogen, hydroxy, C1-C6 alkoxy, amino, C1-C10 amino, halogen atom, cyano group, aldehyde group, C1-C6 alkyl carbonyl, C1-C10 alkoxy carbonyl, C1-C10 alkyl amino carbonyl, C1-C6 alkoxy carbonyloxy, C1-C6 alkyl amino carbonyloxy; X respectively represents hydrogen, oxygen, sulfur, nitrogen, carbon; R 3< respectively represents hydrogen, hydroxy, halogen atom, cyano group, ester group, amido group, C1-C10 hydrocarbyl, C1-C6 alkoxy, C1-C4 alkyl carbonyloxy, C1-C4 alkoxy carbonyloxy, C1-C10 nitrogen-containing heterocyclic ring, C1-C10 oxygen-containing heterocyclic ring, C1-C10 sulfur-containing heterocyclic ring; R 4< and R 5< respectively represents hydrogen, C1-C10 hydrocarbyl, C1-C10 nitrogen-containing heterocyclic ring, C1-C10 oxygen-containing heterocyclic ring, C1-C10 sulfur-containing heterocyclic ring; R 4< and R 5< are C1-C10 aliphatic ring, C1-C10 unsaturated carbon ring, C1-C10 nitrogen-containing heterocyclic ring, C1-C10 oxygen-containing heterocyclic ring, C1-10 sulfur-containing heterocyclic ring; R 6< respectively represents hydrogen, hydroxy, amino, C1-C10 hydrocarbyl, C1-C6 alkoxy, C1-C10 amino group, substituted phenyl ring, C1-C10 nitrogen-containing heterocyclic ring, C1-C10 oxygen-containing heterocyclic ring, C1-C10 sulfur-containing heterocyclic ring.

[0010]The compounds shown in general formula (I) have excellent activity against plant viruses, can satisfactorily inhibit tobacco mosaic virus, chilli virus, rice virus, tomato virus, sweet potato virus, potato virus and cucurbits virus and maize dwarf mosaic virus, may effectively prevent and control virus diseases of tobacco, chilli, paddy, tomato, cucurbitaceous vegetable, grain, vegetable, bean and other crops, and is particularly applicable to the prevention and treating of tobacco mosaic. β-carboline, dihydro-β-carboline and tetrahydro-β-carboline alkaloid derivatives shown in general formula (I) have very high in vitro activity against TMV and also show very good in vivo activity against tobacco mosaic virus (TMV), and the in vivo activity of some of β-carboline, dihydro-β-carboline and tetrahydro-β-carboline alkaloid derivatives against tobacco mosaic virus is obviously better than that of commercial variety virazole. Particularly, the activity of compounds Harmalan, Tetrahydroharmane, Harmane, Tetrahydroharmine, I a -1, I b -8, I b -13, I b -15, I c -1-I c -9, I c -12, I c -19, I c -20, I c -24-I c -26, I c -28, I d -1, I d -6 and I d -7 against tobacco mosaic virus at concentration of 100µg/mL is equivalent to the activity of commercial variety ningnanmycin at concentration of 100µg/mL. As far as we know, it is also the first time to report β-carboline, dihydro-β-carboline and tetrahydro-β-carboline alkaloid and their derivatives have activity against plant viruses.

[0011]The compounds shown in general formula (I) can be used as inhibitors of plant viruses directly, or used by adding an agriculturally acceptable vector, or used by forming interactive compositions with other agents against plant viruses, such as: diazosulfide (BTH), tiadinil (TDL), 4-methyl-1,2,3-thiadiazole-5-formic acid (TDLA), DL-β-aminobutyric acid (BABA), virazole, ningnanmycin, phenanthroindolizidine alkaloid Antofine, linked triazole compounds XY-13 and XY-30, virus A, salicylic acid, polyhydroxy dinaphthaldehyde and amino oligosaccharin. Some of these compositions show a synergistic effect and some show an additive effect.

[0012]The compounds shown in general formula (I) have the activity of killing armyworms, cotton bollworms and corn borers as well as culex pipiens.

[0013]The compounds shown in general formula (I) show bactericidal activity against the following 14 kinds of pathogenic bacteria: cucumber fusarium wilt, Cercospora arachidicola, Macrophoma kawatsukai, Alternaria solani, Fusarium graminearumt, potato late blight, Sclerotinia scleotiorum, Botrytis cinerea, Rhizoctonia solani, Phytophthora capsici, Fusarium fujikuroi, Rhizoctonia cereali, Bipolaria maydis and Colletotrichum orbiculare.

[0014]The compounds shown in general formula (I) can be used as insecticides and bactericides directly, or used by adding an agriculturally acceptable vector, or used in combination with other insecticides, miticides and bactericides, such as: tebufenpyrad, chlorfenapyr, etoxazole and fenpyroximate etc.. Some of these compositions show a synergistic effect and some show an additive effect.

Detailed Description of the Synthesis of β-carboline Alkaloids

[0015]The following description and bioassay results are intended to further illustrate but not to limit the present invention.

Synthesis of dihydro-β-carboline alkaloid harmalan

[0016]

Synthesis of indol-3-formaldehyde

[0017]Add 140mL of DMF to a 500mL single-necked flask, add 27mL of POCl 3 at 0 °C, then add 50mL of DMF solution containing 25g (214mmol) of indole and stir them overnight. Add 50mL of water and 150mL of 20% NaOH aqueous solution in turn and heat and reflux them for 6h. Pour the reaction solution into water and conduct suction filtration to obtain 20.6g of brown solid. The yield is 66% and the melting point is 190-192 °C (literature value: 190-192 °C);

Synthesis of (E)-3-(nitrovinyl) indole

[0018]Add 20g (138mmol) of indol-3-formaldehyde, 5.3g (69mmol) of ammonium acetate and 200mL of nitromethane to a 500mL single-necked flask, and heat and reflux them for 8h. Add 200mL of water and 150mL of ethyl acetate and separate the liquid.

[0019]Wash the organic phase with water, dry it and evaporate the solvent under a reduced pressure. Use dichloromethane for column chromatography under normal pressure to obtain 19.1g of yellow solid. The yield is 74% and the melting point is 170-171 °C;

Synthesis of tryptamine

[0020]Add 500mL of tetrahydrofuran to a 1000mL single-necked flask, and add 11.4g (300mmol) of lithium aluminum hydride and 9.4g (50mmol) of (E)-3-(nitrovinyl) indole. Heat and reflux them for 7h. Use water to quench lithium aluminum hydride not fully reacted. Conduct suction filtration, remove the solvent in the filtrate and add ethyl acetate and water to separate liquid. Wash the organic phase with a saturated saline solution, dry it with anhydrous sodium sulfate, remove solvent to obtain a red viscous substance, and dry it naturally to obtain 8.9g of brown solid. The yield is 89% and the melting point is 115-117 °C;

Synthesis of harmalan

[0021]Add 0.5g (3.13mmol) of tryptamine, 40mL of dichloromethane and 2mL of triethylamine to a 100mL single-necked flask. Add 5mL of dichloromethane solution containing 0.27g (3.44mmol) of acetylchloride and react at room temperature for 5h. Wash the reaction solution with a saturated sodium bicarbonate aqueous solution, dry it with anhydrous sodium sulfate and remove the solvent. Add 20mL of toluene, 20mL of chloroform and 3mL of phosphorus oxychloride without the need of purification. Heat and reflux them for 7h. Add sodium carbonate to regulate the reaction solution to be alkaline. Extract the reaction solution with dichloromethane, and wash the organic phase with a saturated saline solution, dry it with anhydrous sodium sulfate and remove the solvent. Use dichloromethane/methanol (10: 1) for column chromatography under normal pressure to obtain 0.35g of brownish yellow solid. The yield is 60% and the melting point is 110-113 °C;

Synthesis of tetrahydroharmane and harmane.

[0022]

Synthesis of tetrahydroharmane

[0023]Add 8.1mL (43.75mmol) of 40% acetaldehyde aqueous solution, 250mL of water and 5 drops of concentrated sulfuric acid to a 500mL single-necked flask. Stir them at room temperature for 0.5h, add 3.50g (21.88mmol) of tryptamine and heat and reflux them for 7h. Add NaOH to regulate pH value to around 10, extract the solution with dichloromethane, wash the organic phase with a saturated saline solution, dry it with anhydrous sodium sulfate, remove the solvent, and use dichloromethane/methanol (5: 1) for column chromatography under normal pressure to obtain 2.53g of brown solid. The yield is 62% and the melting point is 173-175 °C;

Synthesis of harmane

[0024]Add 0.85g (4.57mmol) of tetrahydrocarboline, 0.53g (4.57mmol) of maleic acid, 120mL of water and 0.85g of Pd/C to a 250mL single-necked flask. Heat and reflux them for 8h, conduct suction filtration, wash with water and regulate pH value of the filtrate with NaOH to 9-10 to obtain a large amount of white solid. Conduct suction filtration to obtain 0.5g of white solid. The yield is 60% and the melting point is 244-245 °C;

Synthesis of tetrahydroharmine

[0025]

Synthesis of quaternary ammonium salt

[0026]Add 0.5g (2.36mmol) of harmine, 120mL of ethyl acetate and 0.48g (2.83 mmol) of benzyl bromide to a 250mL single-necked flask. Heat and reflux them for 12h. Conduct suction filtration to obtain 0.67g of light yellow solid. The yield is 74% and the melting point is above 300 °C;

Synthesis of N-benzyl tetrahydroharmine

[0027]Add 0.67g (1.75mmol) of quaternary ammonium salt and 150mL of methanol to a 250mL single-necked flask, and add 30mL of methanol solution containing 0.53g (14.0mmol) of sodium borohydride. Heat and reflux them for 15h. Remove the solvent and add dichloromethane and water to separate liquid. Wash the organic phase with a saturated saline solution, dry it with anhydrous sodium sulfate, remove the solvent, and use dichloromethane/methanol (20: 1) for column chromatography under normal pressure to obtain 0.47g of brown solid. The yield is 88% and the melting point is 147-149 °C;

Synthesis of tetrahydroharmine

[0028]Add 0.70g (2.29mmol) of N-benzyl-protected tetrahydroharmine, 120mL of trifluoroethanol and 0.70g of Pd/C to a 250mL single-necked flask, input hydrogen and stir them overnight. Remove the solvent, and use dichloromethane/methanol (10:1) for column chromatography under normal pressure to obtain 0.37g of light yellow viscous substance. The yield is 80% and the melting point is 195-197 °C;

Embodiment 1: Synthesis of harmol

[0029]

[0030]Add 0.5g (2.36mmol) of harmine, 18mL of glacial acetic acid and 18mL of 40% hydrobromic acid aqueous solution to a 100mL single-necked flask, and heat and reflux them for 10h. Use saturated sodium bicarbonate to regulate pH value to around 8 and generate precipitate. Conduct suction filtration to obtain 0.46g of yellow green solid. The yield is 98% and the melting point is above 300 °C;

Synthesis of bromo and nitro-substituted harmane

Synthesis of bromo-harmane (I a -1 and I a -2)

[0031]

[0032]Add of 0.2g (1.10mmol) of harman and 10mL of glacial acetic acid to a 25mL single-necked flask, add 0.2g (1.10mmol) of NBS, and react at room temperature for 6h. Remove the solvent, wash with saturated sodium bicarbonate, extract with dichloromethane, dry the organic phase with anhydrous sodium sulfate, remove the solvent and use dichloromethane/methanol (40: 1→20: 1) in turn for column chromatography under normal pressure to obtain two kinds of white solid: solid I a -1 0.05g, yield 17%; 1< H NMR(400MHz, CDCl 3 )δ 8.36-8.49(m, 2H, NH and Ar-H), 8.04(d, 3< J HH =6.4Hz, 1H, Ar-H), 7.77-7.84(m, 1H, Ar-H), 7.70(d, 3< J HH =6.4Hz, 1H, Ar-H), 7.18(t, 3< J HH =6.4Hz, 1H, Ar-H), 2.88(s, 3H, CH 3 ). Solid I a -2 0.24 g, yield 83%, melting point 256-257 °C;

Synthesis of nitro-substituted harmane (I a -3 and I a -4)

[0033]

[0034]Add 0.4g (2.20mmol) of harman and 0.93g (10.99mmol) of sodium nitrate to a 50mL single-necked flask, add 20mL of trifluoroacetic acid, and stir them at room temperature for 6h. Add a saturated sodium bicarbonate aqueous solution to the reaction solution to regulate pH value to 10-11 and generate yellow precipitate, and conduct suction filtration to obtain 0.06g of yellow solid I a -3. The yield is 12% and the melting point is 207-210 °C.

[0035]0.36g of light yellow solid I a -4. The yield is 12% and the melting point is above 300 °C.

Embodiment 2: Synthesis of isopropylamino formate(1-methylpyridino[3,4-b]indol-7)-ester (I a -5)

[0036]

[0037]Add 0.5g (2.53mmol) of demethylated harmaline and 50mL of DMF to a 100mL single-necked flask, add 1.5mL of isopropyl isocyanate and 0.08 g (0.758mmol) of triethylamine, and stir them overnight. Add a saturated sodium chloride aqueous solution, extract with ethyl acetate, dry it with anhydrous sodium sulfate and remove the solvent. Use dichloromethane/methanol (20: 1) for column chromatography under normal pressure to obtain 0.50g of white solid. The yield is 70% and the melting point is above 300 °C;

Embodiment 3: Synthesis of dimethylcarbamate(1-methylpyridino[3,4-b]indol-7)-ester (I a -6)

[0038]

[0039]Add 0.4g (2.02mmol) of demethylated harmaline, 150mL of tetrahydrofuran, 0.31g (3.03mmol) of triethylamine and a catalytic amount of DMAP to a 250mL single-necked flask, stir them at room temperature for 0.5h, add 0.33g (3.03mmol) of acyl chloride and stir them overnight. Remove the solvent, add dichloromethane and water to separate liquid, wash the organic phase with a saturated saline solution, dry it with anhydrous sodium sulfate, remove the solvent, and use dichloromethane/methanol (10: 11) for column chromatography under normal pressure to obtain 0.48g of white solid. The yield is 89% and the melting point is 225-227 °C;

[0040]Compounds I a -7-I a -8 are completed through repeating the foregoing steps.

Acetate(1-methylpyridino[3,4-b]indol-7)-ester (I a -7)

[0041]White solid, yield 50%, melting point 237-240 °C;

Tert-valerate(1-methylpyridino[3,4-b]indol-7)-ester (I a -8)

[0042]White solid, yield 85%, melting point 221-222 °C;

Embodiment 4: Synthesis of (S)-3-methyl-2-carbobenzoxyaminobutyrate-(1-methylpyridino [3,4-b]indol-7-ester (I a -9)

[0043]

[0044]Add 0.80g (3.03mmol) of amino acid and 150mL of dichloromethane to a 250mL single-necked flask, and add 0.41g (4.04mmol) of triethylamine, 0.76g (4.04mmol) of EDCI (1-ethyl-(3-dimethylaminopropyl) carbonyldiimide hydrochloride) and 0.50g (4.04mmol) of DMAP (4-dimethylaminopyridine) and stir them overnight. Wash them with water, dry them with anhydrous sodium sulfate, remove the solvent, and use dichloromethane/methanol (20: 1) for column chromatography under normal pressure to obtain 0.8g of white solid. The yield is 92% and the melting point is 69-71 °C;

(1S,3S)-1-methyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formic acid (I b -1)

[0045]

[0046]Add 20g (98.0mmol) of L-tryptophan, 500mL of water, 2mL of concentrated sulfuric acid and 20mL of 40% acetaldehyde aqueous solution to a 1000mL single-necked flask, stir them at room temperature overnight, use strong aqua to regulate pH value to 6-7, separate out white solid and conduct suction filtration to obtain 16.7g of white solid. The yield is 74% and the melting point is 78-280 °C;

[0047]Compounds I b -2 and I b -3 are completed through repeating the foregoing steps.

(1R,3R)-1-methy|-2,3,4,9-tetrahydropyridino[3,4-b] indol-3-formic acid (I b -2)

[0048]White solid, yield 76%, melting point 285-287 °C;

(1S,3S)-1-ethyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formic acid (I b -3)

[0049]2.67g of white solid, yield 44%, melting point 277-280 °C;

Synthesis of 2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formic acid (I b -4)

[0050]

[0051]Add 10.00g (49mmol) of L-tryptophan, 1.96g (49mmol) of NaOH and 100mL of water to a 250mL single-necked flask, and add 5mL of 30% formaldehyde aqueous solution. Heat and reflux them for 3h. Use 3M diluted hydrochloric acid to regulate pH value to around 5 and generate precipitate, conduct suction filtration, wash the filter cakes with water and dry them to obtain 8.32g of white solid. The yield is 88% and the melting point is 278-279 °C;

Synthesis of (1S,3S)-1-phenyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formic acid (I b -5)

[0052]

[0053]Add 2.5g (12.3mmol) of L-tryptophan, 50mL of glacial acetic acid and 1.5g (13.5mmol) of benzaldehyde to a 100mL single-necked flask, heat and reflux them for 12h, remove the solvent, use ammonium hydroxide to regulate pH value to 5-6 and generate precipitate, and conduct suction filtration to obtain 3.1g of white solid. The yield is 86% and the melting point is 197-207 °C;

[0054]Compound I b -6 is completed through repeating the foregoing steps.

[0055](1S,3S)-1-(pyridine-3)-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formic acid (I b -6) Yellow solid, yield 87% and the melting point is 250-253 °C;

Synthesis of (1S,3S)-1-methyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-ethyl formate (I b -13)

[0056]

[0057]Add 16g (69.0mmol) of acid and 500mL of anhydrous ethanol to a 1000mL single-necked flask, add 30mL of thionyl chloride, and heat and reflux them for 5h. Use a saturated sodium bicarbonate aqueous solution to regulate pH value to 9 and generate precipitate, and conduct suction filtration to obtain 16.4g of milky solid, The yield is 92% and the melting point is 136-137 °C;

[0058]Compounds I b -7-I b -12 are completed through repeating the foregoing steps.

(S)-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-ethyl formate (I b -7)

[0059]Light yellow solid, yield 95%, melting point 50-53 °C;

(1S,3S)-1-methyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-butyl formate (I b -8)

[0060]Yellow oily substance, yield 68%;

2,3,4,9-tetrahydropyridino[3,4-b]indol-3-ethyl formate (I b -9)

[0061]Yellow solid, yield 90%, melting point 136-137 °C;

(1S,3S)-1-ethyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-ethyl formate (I b -10)

[0062]Yellow oily substance, yield 68%;

(1S,3S)-1-(pyridine-3)-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-ethyl formate (I b -11)

[0063]White solid, yield 42%, melting point 239-240 °C;

(1R,3R)-1-methy|-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-ethyl formate (I b -12)

[0064]Light yellow solid, yield 92%, melting point 121-122 °C;

1-methyl-pyridino[3,4-b]indol-3-ethyl formate (I a -10) and 1-methyl-pyridino[3,4-b]indol-3-formic acid (I a -11)

[0065]

1-methyl-pyridino[3,4-b]indol-3-ethyl formate (I a -10)

[0066]Add 12.4g (47.7mmol) of tetrahydrocarboline, 3.1g (95.4mmol) of elemental sulfur and 150mL of xylol to a 250mL single-necked flask, and heat and reflux them for 12h. Cool them to separate out flesh pink solid, and conduct suction filtration to obtain 8.4g of flesh color solid. Yellow solid, yield 69%, melting point 217-219 °C;

1-methyl-pyridino[3,4-b]indol-3-formic acid (I a -11)

[0067]Add 2.00g (7.87mmol) of ester, 0.47g (11.81mmol) of NaOH and 60mL of ethanol to a 100mL single-necked flask, and heat and reflux them for 6h. Use 3M diluted hydrochloric acid to regulate pH value to 5-6 and generate precipitate, conduct suction filtration, wash filter cakes with water and dry them to obtain 1.46g of light yellow solid. The yield is 82% and the melting point is above 300 °C;

Synthesis of (E)-3-(1-methyl-pyridino[3,4-b]indol-3)-acrylic acid (I a -14)

[0068]

(1-methyl-pyridino[3,4-b]indol-3)-methanol (I a -12)

[0069]Add 2g (7.4mmol) of ester and 300mL of tetrahydrofuran to a 500mL single-necked flask, add 0.6g (15.7mmol) of lithium aluminum hydride by batch, stir them at room temperature overnight, add water to quench the reaction, conduct suction filtration and remove the solvent of the filtrate to obtain 1.58g of yellow solid. The yield is 95% and the melting point is 195-197 °C;

1-methyl-pyridino[3,4-b]indol-3-formaldehyde (I a -13)

[0070]Add 1.16g (5.47mmol) of alcohol, 3.04g (10.93mmol) of IBX and 60mL of DMSO to a 100mL single-necked flask, and stir them at room temperature overnight. Add 200mL of water, use dichloromethane for extraction, wash the organic phase with a saturated saline solution, dry it with anhydrous sodium sulfate, remove the solvent, and use dichloromethane/methanol (10: 1) for column chromatography under normal pressure to obtain 0.46g of white solid. The yield is 40% and the melting point is 194-196 °C;

(E)-3-(1-methyl-pyridino[3,4-b]indol-3)-acrylic acid (I a -14)

[0071]Add 0.45g (2.14mmol) of aldehyde, 100mL of pyridine and 3 drops of piperidine to a 250mL single-necked flask, add 0.33g (3.21mmol) of malonic acid, and heat and react for 4h. Use 3M diluted hydrochloric acid to regulate pH value of the water phase to 5-6, and conduct suction filtration to obtain 0.51g of yellow solid. The yield is 94% and the melting point is 220-223 °C; 1< H

[0072]Compounds I a -15-I a -16 are completed through repeating the foregoing steps

(E)-3-(1-(thiophene-2)-pyridino[3,4-b]indol-3)-acrylic acid (I a -15)

[0073]Yellow solid, yield 85%, melting point 248-250 °C;

(E)-3-(1-(pyridine-3)-pyridino[3,4-b]indol-3)-acrylic acid (I a -16)

[0074]Yellow solid, yield 50%, melting point >300 °C;

Synthesis of 1-methyl-4,9-dihydro-pyridino[3,4-b]indol-3)-ethyl formate (I b -14)

[0075]

L-tryptophan ethyl ester (6)

[0076]Add 0.50g (24.50mmol) of L-tryptophan and 150mL of ethanol to a 250mL single-necked flask, add 15mL of thionyl chloride, and heat and reflux them for 12h. Remove the solvent to obtain 5.72g of brown viscous substance, with a yield of 98%;

1-methyl-4,9-dihydro-pyridino[3,4-b]indol-3-ethyl formate (I b -14)

[0077]Add 5.72g (24.66mmol) of tryptophan ethyl ester, 150mL of dichloromethane and 2.99g (29.59mmol) of triethylamine to a 250mL single-necked flask, add 2.13g (27.12mmol) of acetylchloride and stir them at room temperature for 5h after dropwise addition. Use a saturated sodium bicarbonate to wash the reaction solution, extract with dichloromethane, wash the organic phase with a saturated saline solution, dry it with anhydrous sodium sulfate and remove the solvent to obtain 5.96g of brown viscous substance. Dissolve it in chloroform, add 24mL of POCl 3 , and heat and reflux them for 5h. Extract with dichloromethane, dry with anhydrous sodium sulfate, remove the solvent, and use dichloromethane/methanol (10: 1) for column chromatography under normal pressure to obtain 2.85g of yellow solid. Yellow solid, yield 45%, melting point 85-87 °C;

(1S,3S)-1-methyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formylhydrazine (I b -15)

[0078]

[0079]Add 1.00g (4.1mmol) of methyl ester, 50mL of ethanol and 1.02g (16.4mmol) of 80% hydrazine hydrate to a 100mL single-necked flask, and heat and reflux them for 6h. Remove the solvent, dissolve it in ethyl acetate, wash it with a saturated saline solution, dry it with anhydrous sodium sulfate, and remove the solvent to obtain 0.98g of light yellow solid, with a yield of 98%. White solid, yield 98% and melting point 100-103 °C;

Synthesis of (1S,3S)-N-butyl-1-methyl-2,3,4,9-tetrahydro-pyridino[3,4-b]indol-3-formamide (I b -16)

[0080]

[0081]Add 0.5g (2.05mmol) of methyl ester and 15mL of n-butylamine to a 25mL single-necked flask, and stir them at room temperature overnight. Remove the solvent, add dichloromethane to dissolve it, wash it with a saturated saline solution, dry with anhydrous sodium sulfate and remove the solvent. Use dichloromethane/methanol (20: 1) for column chromatography under normal pressure to obtain 0.35g of white solid. The yield is 60% and the melting point is 207-210 °C;

[0082]Compound I b -18 is completed through repeating the foregoing steps.

(1S,3S)-N-(2-ethoxyl)-1-methyl-2,3,4,9-tetrahydro-pyridino[3,4-b]indol-3-formamide (I b -18)

[0083]White solid, yield 64%, melting point 110-112 °C;

Synthesis of (1S,3S)-N-cyclohexyl-1-methyl-2,3,4,9-tetrahydro-pyridino[3,4-b]indol-3-formamide (I b -17)

[0084]

[0085]White solid, yield 50%, melting point 231-233 °C;

[0086]Compounds I b -19, I b -20 are completed through repeating the foregoing steps.

(1S,3S)-N-((dimethyl amino)methyl)-1-methyl-2,3,4,9-tetrahydro-pyridino[3,4-b]indol-3-formamide (I b -19)

[0087]White solid, yield 55%;

(1S,3S)-N-((tetrahydrofuran-2)-methyl)-1-methyl-2,3,4,9-tetrahydro-pyridino[3,4-b]indol-3-formamide (I b -20)

[0088]Yellow solid, yield 47%, melting point 95-97 °C;

(1S,3S)-N'-benzylidene-1-methyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formylhydrazine (I c -1)

[0089]

[0090]Add 0.50g (2.05mmol) of hydrazide and 40mL of toluene to a 100mL single-necked flask, add 0.44g (4.10mmol) of benzaldehyde, and heat and reflux them for 5h. Conduct suction filtration and wash with toluene to obtain 0.50g of yellow solid. The yield is 74% and the melting point is 200-204 °C;

[0091]Compounds I c -2-I c -29 are completed through repeating the foregoing steps.

(1S,3S)-N'-(4-tert-butyl benzylidene)-1-methyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formylhydrazine (I c -2)

[0092]Yellow solid, yield 72%, melting point 139-143 °C;

(1S,3S)-N'-(4-dimethyl amino benzylidene)-1-methyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formylhydrazine (I c -3)

[0093]Yellow solid, yield 73%, melting point 215-220 °C;

(1S,3S)-N'-(4-nitrobenzylidene)-1-methyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formylhydrazine (I c -4)

[0094]Yellow solid, yield 74%, melting point 222-227 °C;

(1S,3S)-N'-(4-chlorobenzylidene)-1-methyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formylhydrazine (I c -5)

[0095]Yellow solid, yield 81%, melting point 140-145 °C;

(1S,3S)-N-(2,4-dichlorobenzylidene)-1-methyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formylhydrazine (I c -6)

[0096]Yellow solid, yield 85%, melting point 211-213 °C;

(1S,3S)-N'-(3,4-dichlorobenzylidene)-1-methyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formylhydrazine (I c -7)

[0097]Yellow solid, yield 79%, melting point 189-193 °C;

(1S,3S)-N'-(4-methoxybenzylidene)-1-methyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formylhydrazine (I c -8)

[0098]Yellow solid, yield 69%, melting point 138-143 °C;

(1S,3S)-N'-(3-methoxybenzylidene)-1-methyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formylhydrazine (I c -9)

[0099]Yellow solid, yield 63%, melting point 186-190 °C;

(1S,3S)-N'-(2-methoxybenzylidene)-1-methyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formylhydrazine (I c -10)

[0100]Yellow solid, yield 82%, melting point 180-183 °C;

(1S,3S)-N'-(3,4-dimethoxybenzylidene)-1-methyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formylhydrazine (I c -11)

[0101]Light yellow solid, yield 91%, melting point 203-206 °C;

(1S,3S)-N'-((benzo[d][1,3]dioxymethylene-5)-methylene-1-methyl-2,3,4,9-tetrahydropyridino[3,4-b]indol-3-formylhydrazine (I c -12)

[0102]Yellow solid, yield 83%, melting point 199-203 °C;

(1S,3S)-N'-