16063-70-0

Basic information

• Product Name: 2,3,5-Trichloropyridine
• Synonyms: 2,3,5-trichloro-pyridin;2,3,5-TRICHLOROPYRIDINE;Trichloropyridine,98%;2,3,5-TRICHLOROPYRIDINE 98+%;3,5,6-Trichloropyridine;Pyridine, 2,3,5-trichloro-;5-Trichloropyridine;2,3,5 - cross-linked with pyridine
• CAS NO: 16063-70-0
• Molecular Formula: C₅H₂Cl₃N
• Molecular Weight: 182.44
• EINECS: 407-270-2
• Product Categories: Pyridine;Chloropyridines;Halopyridines;C5Heterocyclic Building Blocks;Halogenated Heterocycles;Heterocyclic Building Blocks;Pyridines;Chlorinated heterocyclic series;Building Blocks;C5;C5 to C6;Chemical Synthesis;Halogenated Heterocycles;Heterocyclic Building Blocks;alkyl chloride
• Mol File: 16063-70-0.mol
• Article Data: 28

Chemical Properties

• Melting Point: 46-50 °C(lit.)
• Boiling Point: 219 °C(lit.)
• Flash Point: >230 °F
• Appearance: Off-white to pale yellow/Solid
• Density: 1.539 g/cm³
• Vapor Pressure: 0.213mmHg at 25°C
• Refractive Index: 1.572
• Storage Temp.: under inert gas (nitrogen or Argon) at 2-8°C
• PKA: -2.92±0.10(Predicted)
• Water Solubility: Slightly soluble in water.
• BRN: 119384
• CAS DataBase Reference: 2,3,5-Trichloropyridine(CAS DataBase Reference)
• NIST Chemistry Reference: 2,3,5-Trichloropyridine(16063-70-0)
• EPA Substance Registry System: 2,3,5-Trichloropyridine(16063-70-0)

Safety Data

• Hazard Codes: Xi
• Statements: 52/53-36/37/38
• Safety Statements: 61-37/39-26
• RIDADR: UN 2811 6.1/PG 3
• WGK Germany: 2
• RTECS: UU0525000
• Hazardous Substances Data: 16063-70-0(Hazardous Substances Data)

Usage

Chemical Properties

Beige powder

Uses

2,3,5-Trichloropyridine may be used in the synthesis of 3,5-dichloro-2-arylpyridines via palladium acetate-catalyzed ligand-free Suzuki reaction with arylboronic acids.

General Description

Separation and migration behavior of 2,3,5-trichloropyridine has been studied by micellar electrokinetic chromatography. Crystal structure of 2,3,5-trichloropyridine has been reported. Mol-ecules of 2,3,5-trichloropyridine in crystal are stacked along the short a axis and forms a layer structure. 2,3,5-Trichloropyridine is reported to undergo nucleophilic displacement reaction in ionic liquid to afford the corresponding 2-aryloxylpropionate.

InChI:InChI=1/C5H2Cl3N/c6-3-1-4(7)5(8)9-2-3/h1-2H

Synthetic route

2,3,5,6-tetrachloropyridine (2402-79-1) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
With 5%-palladium/activated carbon; hydrogen; potassium hydroxide In 5,5-dimethyl-1,3-cyclohexadiene; water at 60℃; under 4500.45 Torr; for 6h; Reagent/catalyst; Solvent; Pressure; Autoclave;	99.1%
With sodium hydroxide In benzene

2,3,4,5,6-pentachloropyridine (2176-62-7) → 2,3,6-trichloropyridine (6515-09-9) + 2,3,5-trichloropyridine (16063-70-0) + 2,3,5,6-tetrachloropyridine (2402-79-1)

Conditions	Yield
With ammonium chloride; dimethyl methane phosphonate; zinc In water at 85 - 90℃; Product distribution; other ammonium salts; other methylphosphonates/phosphates;	A 0.9% B 1% C 97.6%

2,3,4,5-tetrachloro-pyridine (2808-86-8) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
With tetramethylammonium methylphosphonic acid methyl ester; dimethyl methane phosphonate; zinc In water at 85℃; other ammonium salts; other methylphosphonates;other solvent(s). Object of study: selectivity of reaction;	96.4%
With ammonium chloride; zinc In methanol; water at 72℃; for 2h; Solvent; Temperature;	90%
With pyridine; 5%-palladium/activated carbon; hydrogen In methanol; water at 50℃; under 3750.38 Torr; Reagent/catalyst; Temperature; Pressure;	86.2%
With tetramethylammonium methylphosphonic acid methyl ester; dimethyl methane phosphonate; zinc In water at 85℃; for 1h; Yield given;
With ammonium chloride; zinc In methanol; water at 70 - 80℃; Temperature; Solvent; Large scale;	1.4 kg

3,5,6-trichloro-2-hydrazinopyridine (55933-94-3) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
	95%
With sodium hypochlorite; sodium hydroxide In water at 70 - 75℃; for 1h; Green chemistry;	95%
	93%

2,4,4-trichloro-4-formylbutyronitrile (75272-53-6) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
With hydrogenchloride; phosphorus pentachloride In N,N-dimethyl-formamide at 60 - 100℃; for 1h;	89%
With hydrogenchloride at 180℃; for 2h;	85%
With hydrogenchloride at 80℃; for 3h;	82.1%

3,5-Dichloro-2-pyridinol (5437-33-2) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
With trichlorophosphate at 190℃; for 3h; in sealed tube;	87%

2,2,4'-trichloro-5-oxopentanonitrile (98775-57-6) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
With hydrogenchloride; trichlorophosphate In N,N-dimethyl-formamide at 115℃; for 0.333333h;	79%
With trichlorophosphate In benzene at 190℃; for 1h; in autoclave;	76%
Multi-step reaction with 2 steps 1: 91 percent / dry HCl / dimethylformamide / 0.25 h / 110 °C 2: 87 percent / POCl3 / 3 h / 190 °C / in sealed tube View Scheme
Multi-step reaction with 3 steps 1: 90 percent / dry HCl / dibutyl ether / 1 h / 90 °C 2: 95 percent / triethylamine / benzene / 4 h / Heating 3: 87 percent / POCl3 / 3 h / 190 °C / in sealed tube View Scheme

2,3,4,5,6-pentachloropyridine (2176-62-7) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
With tetrabutylammomium bromide; sodium hydroxide; zinc In toluene at 50℃; for 6h; Green chemistry;	73%
With ammonium hydroxide In toluene
With sodium hydroxide; zinc In benzene
With sodium hypochlorite; sodium hydrogencarbonate; hydrazine In propylene glycol dimethyl ether; water

chloral (75-87-6) + acrylonitrile (107-13-1) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
copper(l) chloride In acetonitrile at 190℃; for 0.5h;	65%
copper(l) chloride In acetonitrile at 190℃; for 0.5h;	65%
With [bmim]BF4; copper(l) chloride In acetonitrile at 120℃;	41%
In acetonitrile at 105 - 190℃; Product distribution; various inorg. catalyst, various yield;
copper(l) chloride In acetonitrile at 120 - 175℃; for 19h;

Pyridin-Palladium(II)-chlorid-Komplex → 2-chloropyridine (109-09-1) + 2,3-dichloro-pyridine (2402-77-9) + 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
With chlorine In cyclohexane at 75℃; for 1h;	A 9% B 62% C 4.5%

3,5-dichloropyridine-2-carboxylic acid (81719-53-1) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
With tert-butylhypochlorite; dichloromethane; oxygen; sodium hydrogencarbonate at 60℃; for 20h; Green chemistry;	42%

pyridine (110-86-1) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
With hydrogenchloride; chlorine at 115 - 120℃;
With phosphorus pentachloride at 210 - 220℃;

phosgene (75-44-5) + 3,5-dichloro-1-methyl-1H-pyridin-2-one (4214-83-9) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
With toluene at 150℃;

trichloroacetonitrile (545-06-2) + acrolein (107-02-8) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
With copper(I) chloride; trichlorophosphate 1. 5 h, 90 deg C, benzene, autoclave; 2. 30 min, 180 deg C.; Yield given. Multistep reaction;

1-methyl-3.5-dichloro-pyridone-(2) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
With phosphorus pentachloride; trichlorophosphate at 180℃; im Rohr;

3,5-dichloro-1-methyl-1H-pyridin-2-one (4214-83-9) + phosphorus pentachloride (10026-13-8, 874483-75-7) + trichlorophosphate (10025-87-3, 12599-09-6, 63736-95-8) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
at 180℃;

barium salt of/the/ pyridine-disulfonic acid-(3.5) → 2,3,5-trichloropyridine (16063-70-0) + 3,5-dichloropyridine (2457-47-8)

Conditions	Yield
With phosphorus pentachloride at 200℃;

3,5-dichloropyridin-2-amine (4214-74-8) → 2,3,5-trichloropyridine (16063-70-0) + 3.5-dichloro-2-oxy-pyridine

Conditions	Yield
With hydrogenchloride; potassium nitrite

hydrogenchloride (7647-01-0) + 3,5-dichloropyridin-2-amine (4214-74-8) + potassium nitrite → 2,3,5-trichloropyridine (16063-70-0) + 3.5-dichloro-2-oxy-pyridine

2-(trichloromethyl)-3,5-dichloropyridine (1128-16-1) → tetrachloromethane (56-23-5) + 2,3,5-trichloropyridine (16063-70-0) + 2,3,5-trichloro-6-(trichloromethyl)pyridine (7041-24-9) + HCl

Conditions	Yield
With chlorine at 200℃; Title compound not separated from byproducts;
With chlorine at 200℃; Rate constant;

2-hydroxy-3,3,5-trichloro-3,4-dihydropyridine (115168-33-7) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
Multi-step reaction with 2 steps 1: 95 percent / triethylamine / benzene / 4 h / Heating 2: 87 percent / POCl3 / 3 h / 190 °C / in sealed tube View Scheme

2-aminopyridine (504-29-0) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
Multi-step reaction with 3 steps 1: alcohol; chlorine 2: alcohol; chlorine 3: potassium nitrite; hydrochloric acid View Scheme
Multi-step reaction with 2 steps 1: alcohol; chlorine 2: potassium nitrite; hydrochloric acid View Scheme

5-chloro-2-pyridylamine (1072-98-6) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
Multi-step reaction with 2 steps 1: alcohol; chlorine 2: potassium nitrite; hydrochloric acid View Scheme

2,3,5,6-tetrachloropyridine (2402-79-1) → 2,3,5-trichloropyridine (16063-70-0) + 3,5-dichloropyridine (2457-47-8)

Conditions	Yield
With ammonium chloride; zinc In 1,4-dioxane; water at 90 - 92℃; for 12h; Product distribution / selectivity;	A 7.7 %Chromat. B 77.8 %Chromat.

3,5-dichloropyridin-2-amine (4214-74-8) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
With sodium nitrite In hydrogenchloride; hexane; water
With hydrogenchloride; sodium nitrite In water at -20 - 20℃; for 4h;

chloral (75-87-6) + acrylonitrile (107-13-1) + copper(l) chloride → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
In acetonitrile	11.1 g (61% theory)

ruthenium(II)dichloro-tris-triphenylphosphine + 3-Methoxypropionitrile (110-67-8) + chloral (75-87-6) + acrylonitrile (107-13-1) → 2,3,5-trichloropyridine (16063-70-0)

ammonium hydroxide (1336-21-6) + 2,3,4,5,6-pentachloropyridine (2176-62-7) + 1-methoxy-2-propanol (107-98-2) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
In water; toluene

2,3,5-trichloro-4-hydrazino-pyridine (55933-95-4) → 2,3,5-trichloropyridine (16063-70-0)

Conditions	Yield
With sodium hypochlorite In tetrahydrofuran

2,3,5-trichloropyridine (16063-70-0) + propargyl alcohol (107-19-7) → 3,5-dichloro-2-(prop-2-ynyloxy)-pyridine

Conditions	Yield
Stage #1: propargyl alcohol With sodium hydride In tetrahydrofuran at 0 - 45℃; Stage #2: 2,3,5-trichloropyridine In tetrahydrofuran at 20 - 45℃; for 24h;	100%

2,3,5-trichloropyridine (16063-70-0) + 2-amino-benzenethiol (137-07-5) → 3-chloro-1-azaphenothiazine (3493-96-7)

Conditions	Yield
With potassium hydroxide In water; N,N-dimethyl-formamide for 4h; Reflux;	99.7%

2,3,5-trichloropyridine (16063-70-0) → 3,5-dichloro-2-bromopyridine (14482-51-0)

Conditions	Yield
With trimethylsilyl bromide In propiononitrile at 100℃; for 14h;	99%
With hydrogen bromide; propionic acid In water at 80℃; Reagent/catalyst; Solvent;	96.8%

2,3,5-trichloropyridine (16063-70-0) → (3,5-dichloro-2-pyridyl)hydrazine (104408-23-3)

Conditions	Yield
With hydrazine hydrate In ethanol at 80℃; for 24h;	96%
With hydrazine hydrate	95%
With hydrazine hydrate In ethanol at 80 - 90℃;	94.5%

2,3,5-trichloropyridine (16063-70-0) → 5-chloro-2,3-difluoropyridine (89402-43-7)

Conditions	Yield
With potassium fluoride; C6H10BNO4 In dimethyl sulfoxide at 60℃; for 5h; Solvent; Temperature;	95%
With potassium fluoride; 18-crown-6 ether; potassium carbonate; cesium fluoride In sulfolane; dimethyl sulfoxide at 120 - 200℃; for 3h;	90%
Multi-step reaction with 2 steps 1: 36.1 percent / KF; CsF; K2CO3 / [Bmim]BF4 / 10 h / 200 °C 2: 68.8 percent / CsF; K2CO3; [Bmim]BF4 / 8 h / 100 - 110 °C / 200 Torr View Scheme

2,3,5-trichloropyridine (16063-70-0) + 2-methoxy-phenylamine (90-04-0) → 3,5-dichloro-N-(2-methoxyphenyl)pyridine-2-amine

Conditions	Yield
With potassium carbonate; palladium diacetate; 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene In 1,2-dimethoxyethane at 85℃; for 2.5h;	94.7%

2,3,5-trichloropyridine (16063-70-0) + 2-methyl-7-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-2H-indazole (845751-67-9) → 7-(3,5-dichloro-pyridin-2-yl)-2-methyl-2H-indazole (845751-68-0)

Conditions	Yield
With potassium phosphate; tetrakis(triphenylphosphine) palladium(0) In DMF (N,N-dimethyl-formamide); water at 65℃; for 16h;	93%

2,3,5-trichloropyridine (16063-70-0) + p-cresol (106-44-5) → 2-(4-Methylphenoxy)-3,5-dichlorpyridin (28232-17-9)

Conditions	Yield
With copper(l) iodide; N,N,N,N,-tetramethylethylenediamine; caesium carbonate In dimethyl sulfoxide at 110℃; for 24h; Inert atmosphere; regioselective reaction;	93%

2,3,5-trichloropyridine (16063-70-0) + 4-Chlorophenylboronic acid (1679-18-1) → 3,5-dichloro-2-(4-chlorophenyl)pyridine (161949-47-9)

Conditions	Yield
With palladium diacetate; sodium carbonate In water; N,N-dimethyl-formamide at 60℃; for 12h; Suzuki coupling;	91%

2,3,5-trichloropyridine (16063-70-0) + 4-methylphenylboronic acid (5720-05-8) → 3,5-dichloro-2-p-tolylpyridine (1204385-79-4)

Conditions	Yield
With palladium diacetate; sodium carbonate In water; N,N-dimethyl-formamide at 60℃; for 12h; Suzuki coupling;	90%

2,3,5-trichloropyridine (16063-70-0) + (RS)-2-(4-hydroxyphenoxy)propionic acid (94050-90-5, 95977-31-4, 105118-15-8, 67648-61-7) → D-2-[4-(3,5-dichloro-pyridin-2-yloxy)-phenoxy]-propionic acid (60074-25-1)

Conditions	Yield
With potassium carbonate at 75℃; for 4.5h; Reagent/catalyst; Temperature;	90%

2,3,5-trichloropyridine (16063-70-0) + 2-Methoxyphenylboronic acid (5720-06-9) → C12H9Cl2NO

Conditions	Yield
With potassium fluoride; tetrakis(triphenylphosphine) palladium(0) In toluene at 100℃; for 5h;	90%
With potassium fluoride; tetrakis(triphenylphosphine) palladium(0) In toluene at 100℃; for 5h;	90%

2,3,5-trichloropyridine (16063-70-0) → 2,3,5-trichloro-4-iodopyridine (406676-23-1)

Conditions	Yield
With iodine; lithium diisopropyl amide In tetrahydrofuran; hexane at -75℃;	89%
Stage #1: 2,3,5-trichloropyridine With lithium diisopropyl amide In tetrahydrofuran at -78℃; for 2h; Inert atmosphere; Stage #2: With iodine In tetrahydrofuran at -78℃; for 2h; Inert atmosphere;	75%

2,3,5-trichloropyridine (16063-70-0) + 4-fluoroboronic acid (1765-93-1) → 3,5-dichloro-2-(4-fluorophenyl)pyridine (1204385-81-8)

Conditions	Yield
With palladium diacetate; sodium carbonate In water; N,N-dimethyl-formamide at 60℃; for 12h; Suzuki coupling;	89%

2,3,5-trichloropyridine (16063-70-0) + 1-Naphthylboronic acid (13922-41-3) → 3,5-dichloro-2-(naphthalen-1-yl)pyridine (1204385-86-3)

Conditions	Yield
With palladium diacetate; sodium carbonate In water; N,N-dimethyl-formamide at 60℃; for 12h; Suzuki coupling;	89%

2,3,5-trichloropyridine (16063-70-0) + phenylboronic acid (98-80-6) → 3,5-dichloro-2-phenylpyridine (10469-01-9)

Conditions	Yield
With palladium diacetate; sodium carbonate In water; N,N-dimethyl-formamide at 60℃; for 12h; Suzuki coupling;	89%
With palladium diacetate; potassium carbonate; triphenylphosphine In methanol; acetonitrile at 50℃; for 24h; Suzuki Coupling; Inert atmosphere; regioselective reaction;	86%

6-methoxypyridine-3-ol (51834-97-0) + 2,3,5-trichloropyridine (16063-70-0) → 5-(3,5-dichloro-pyridin-2-yloxy)-2-methoxy-pyridine (548763-85-5)

Conditions	Yield
With potassium hydroxide In dimethyl sulfoxide	88%

2,3,5-trichloropyridine (16063-70-0) + (meta-(trifluoromethyl)phenyl)boronic acid (1423-26-3) → 3,5-dichloro-2-(3-(trifluoromethyl)phenyl)pyridine (1204385-83-0)

Conditions	Yield
With palladium diacetate; sodium carbonate In water; N,N-dimethyl-formamide at 60℃; for 12h; Suzuki coupling;	88%

2,3,5-trichloropyridine (16063-70-0) → 3,5-dichloropyridine (2457-47-8)

Conditions	Yield
With acetic acid; zinc In water at 65 - 95℃; for 1 - 5.25h; Product distribution / selectivity;	87.3%

2,3,5-trichloropyridine (16063-70-0) + 2-Methylphenylboronic acid (16419-60-6) → 3,5-dichloro-2-o-tolylpyridine (1204385-80-7)

Conditions	Yield
With palladium diacetate; sodium carbonate In water; N,N-dimethyl-formamide at 60℃; for 12h; Suzuki coupling;	87%

2,3,5-trichloropyridine (16063-70-0) → 2-Fluoro-3,5-dichloropyridine (823-56-3)

Conditions	Yield
With potassium fluoride In sulfolane at 180℃; for 20h;	86%
With potassium fluoride In sulfolane at 155 - 160℃; for 8h; Solvent; Temperature;

Thien-3-ylboronic acid (6165-69-1) + 2,3,5-trichloropyridine (16063-70-0) → 3,5-dichloro-2-(thiophen-3-yl)pyridine (1204385-85-2)

Conditions	Yield
With palladium diacetate; sodium carbonate In water; N,N-dimethyl-formamide at 60℃; for 12h; Suzuki coupling;	86%

2,3,5-trichloropyridine (16063-70-0) + 4-methoxyphenylboronic acid (5720-07-0) → 3,5-dichloro-2-(4-methoxyphenyl)pyridine (1204385-82-9)

Conditions	Yield
With palladium diacetate; sodium carbonate In water; N,N-dimethyl-formamide at 60℃; for 12h; Suzuki coupling;	85%

2,3,5-trichloropyridine (16063-70-0) + sodium methylate (124-41-4) → 5-chloro-1,2-dimethoxypyridine

Conditions	Yield
In dimethyl sulfoxide at 90℃; for 2h; methoxylation;	83%

Upstream product

• 4214-83-9 3,5-dichloro-1-methyl-1H-pyridin-2-one 
• 10026-13-8 phosphorus pentachloride 
• 10025-87-3 trichlorophosphate 
• 4214-74-8 3,5-dichloropyridin-2-amine 
• 7647-01-0 hydrogenchloride 
• 1128-16-1 2-(trichloromethyl)-3,5-dichloropyridine 
• 75-87-6 chloral 
• 107-13-1 acrylonitrile 
• 110-67-8 3-Methoxypropionitrile 
• 16110-09-1 2,5 dichloropyridine 
• 55934-03-7 C₆H₃Cl₃N₂O₂ 
• 81719-53-1 3,5-dichloropyridine-2-carboxylic acid 
• 700-16-3 Pentafluoropyridine 
• 110-86-1 pyridine 

Downstream Products

• 104408-23-3 (3,5-dichloro-2-pyridyl)hydrazine 
• 4214-74-8 3,5-dichloropyridin-2-amine 
• 60074-46-6 methyl 2-[4-(3,5-dichloropyridin-2-yloxy)-phenoxy]-propionate 
• 60074-47-7 ethyl 2-{p-[(3,5-dichloro-pyridin-2-yl)oxy]phenoxy}propionate 
• 89402-43-7 5-chloro-2,3-difluoropyridine 
• 87035-49-2 (+)-2-[4-(5-chloro-3-fluoropyridin-2-yloxy)-phenoxy]-propionic acid methyl ester 
• 85331-33-5 2-Cyano-3,5-dichloropyridine 
• 888740-19-0 3-{2-[(3,5-dichloropyridine-2-yl)oxy]-4-isopropoxyphenyl}propanoic acid ethyl ester 
• 548763-85-5 5-(3,5-dichloro-pyridin-2-yloxy)-2-methoxy-pyridine 
• 60075-03-8 4-(3,5-dichloro-pyridine-2-yloxy)-phenol 
• 87394-60-3 4-(3,5-dichloro-2-pyridyl)piperazine 
• 14482-51-0 3,5-dichloro-2-bromopyridine 
• 1283024-42-9 3,5-dichloro-2-(2-chlorobenzyl)pyridine 
• 1283024-23-6 3,5-dichloro-2-(phenylthio)pyridine 

Relevant articles and documents

Eine neue, einfache Synthese von 2,3,5-Trichlorpyridin

A simple synthesis of 2,3,5-trichloropyridine by the copper-catalyzed free radical addition of chloral to acrylonitrile with or without isolation of the primary 1:1 adduct, 4-formyl-2,4,4-trichlorobutyronitrile (1), is described.

Halopyridines. I. Synthesis of 3,5-Dichloro-2-pyridone and 2,3,5-Trichloropyridine

Trichloroacetonitrile reacts with acrolein to give 2,2,4-trichloro-5-oxopentanonitrile, the cyclization of which to chloropyridines has been examined.

Continuous production process of 2, 3, 5-trichloropyridine

According to a continuous production process of 2, 3, 5-trichloropyridine, a continuous tubular chlorinator is adopted, pyridine is taken as a starting raw material, chlorination reaction is continuously carried out step by step by virtue of a catalyst 1 and a catalyst 2 which are independently researched and developed, and 2, 5-dichloropyridine and 2, 3, 5-trichloropyridine are prepared in sequence. In the preparation process of a catalyst 1 and a catalyst 2, the mass ratio of 1-chloropropane to imidazole to 2-chloroethyl diphenylphosphine to nickel tetracarbonyl is 1.2: 1: 3.7: 2.5, and the mass ratio of 1-chloropropane to imidazole to 2-chloroethyl diphenylphosphine to sodium hexachlororhodate hydrate is 1.2: 1: 3.7: 15. By means of the continuous tubular chlorinator, cheap and easily available pyridine is used as a starting raw material, chlorine atoms are introduced step by step through catalytic chlorination, the atom economy is good, the reaction selectivity is good, the yield of 2, 3, 5-trichloropyridine can be stabilized at 80% or above, the production efficiency is high, the process is easy to control, and the method is environmentally friendly and suitable for industrial production.

Preparation method of 2, 3, 5-trichloropyridine

The invention relates to the field of organic synthesis, in particular to a preparation method of 2, 3, 5-trichloropyridine. According to the invention, in a mixed solvent composed of an organic solvent and water, 2, 3, 4, 5-tetrachloropyridine is reduced by using zinc powder, such that 2, 3, 5-trichloropyridine is prepared. The preparation method of 2, 3, 5-trichloropyridine has the advantages ofhigh yield and high purity, and is environment-friendly, simple and convenient to operate.