2075-45-8

Basic information

• Product Name: 4-Bromopyrazole
• Synonyms: 4-bromo-pyrazol;4-Brompyrazole;Pyrazole, 4-bromo-;4-BROMO-1H-PYRAZOLE;4-BROMOPYRAZOLE;AKOS B001462;93℃-96℃;4-Bromopyrazole,98%
• CAS NO: 2075-45-8
• Molecular Formula: C₃H₃BrN₂
• Molecular Weight: 146.97
• Product Categories: Azoles;blocks;Bromides;Heterocycles;Halides;Pyrazoles & Triazoles;Halogenated;Organohalides;Pyrazole;CHIRAL CHEMICALS;Pyrazoles & Triazoles;Building Blocks;Halogenated Heterocycles;Heterocyclic Building Blocks;Pyrazoles;PyrazolesHeterocyclic Building Blocks;Amines;Aromatics;Building Blocks;C3 to C5;Chemical Synthesis;Halogenated Heterocycles;Heterocyclic Building Blocks
• Mol File: 2075-45-8.mol
• Article Data: 29

Chemical Properties

• Melting Point: 93-96 °C(lit.)
• Boiling Point: 250-260 °C(lit.)
• Flash Point: 108.038 °C
• Appearance: White to cream/Crystalline Powder
• Density: 1.5979 (rough estimate)
• Vapor Pressure: 0.027mmHg at 25°C
• Refractive Index: 1.5260 (estimate)
• Storage Temp.: Inert atmosphere,Room Temperature
• Solubility: Chloroform, DMSO, Methanol
• PKA: 12.71±0.50(Predicted)
• Water Solubility: Slightly soluble in water.
• CAS DataBase Reference: 4-Bromopyrazole(CAS DataBase Reference)
• NIST Chemistry Reference: 4-Bromopyrazole(2075-45-8)
• EPA Substance Registry System: 4-Bromopyrazole(2075-45-8)

Safety Data

• Hazard Codes: Xi
• Statements: 36/37/38
• Safety Statements: 26-37/39
• WGK Germany: 3
• RTECS: UQ6200000
• HazardClass: IRRITANT
• Hazardous Substances Data: 2075-45-8(Hazardous Substances Data)

Usage

Chemical Properties

White to cream crystalline powder

Uses

Different sources of media describe the Uses of 2075-45-8 differently. You can refer to the following data:
1. 4-Bromopyrazole can be used as starting material employed in a synthesis of 1,4′-bipyrazoles and in suzuki reaction.
2. suzuki reaction
3. As a mono substituted pyrozole, 4-Bromopyrazole can be used as Inhibitor of human liver alcohol dehydrogenase and used in mutagenicity study with the L-arabinose resistance test of Salmonella typhimurium.

General Description

4-Bromopyrazole is a pyrazole derivative. It is reported to react with titanium tetrachloride to afford binary adducts. Mutagenicity of 4-bromopyrazole has been tested using the L-arabinose forward mutation assay of Salmonella typhimurium. It is reported to inhibit the oxidative phosphorylation, the ATP-32P exchange reaction, and energy dependent and independent calcium uptake.

InChI:InChI=1/C3H3BrN2/c4-3-1-5-6-2-3/h1-2H,(H,5,6)

Synthetic route

NH-pyrazole (288-13-1) → 4-bromo-1H-pyrazole (2075-45-8)

Conditions	Yield
With bromine In dichloromethane at 0℃;	100%
With N-Bromosuccinimide In water at 20 - 25℃;	100%
With N-Bromosuccinimide In water at 20℃;	100%

3,5-pyrazoledicarboxylic acid (3112-31-0) → 4-bromo-1H-pyrazole (2075-45-8)

Conditions	Yield
With bromine

potassium 4-bromopyrazolate + Methyl 4-pyridazinyl ketone (50901-46-7) → 4-bromo-1H-pyrazole (2075-45-8) + C6H5N2O(1-)*K(1+)

Conditions	Yield
In dimethyl sulfoxide at 24.9℃; Equilibrium constant;

4-bromo-1H-pyrazole-3-carboxylic acid (13745-17-0) → 4-bromo-1H-pyrazole (2075-45-8)

C10H5BrF2N2O → 4-bromo-1H-pyrazole (2075-45-8)

Conditions	Yield
With phosphate buffer at 25℃; Kinetics;

C11H9BrN2O → 4-bromo-1H-pyrazole (2075-45-8)

Conditions	Yield
With phosphate buffer at 25℃; Kinetics;

C11H9BrN2O → 4-bromo-1H-pyrazole (2075-45-8)

Conditions	Yield
With phosphate buffer at 25℃; Kinetics;

C10H4BrClF2N2O → 4-bromo-1H-pyrazole (2075-45-8)

Conditions	Yield
With phosphate buffer at 25℃; Kinetics;

(4-bromo-1H-pyrazol-1-yl)(p-tolyl)methanone → 4-bromo-1H-pyrazole (2075-45-8)

Conditions	Yield
With phosphate buffer at 25℃; Kinetics;

(S)-flurbiprofenyl 4-bromopyrazolide → 4-bromo-1H-pyrazole (2075-45-8) + (S)-(+)-flurbiprofen (5104-49-4, 51543-38-5, 51543-39-6, 51543-40-9)

Conditions	Yield
With water; sodium hydroxide at 4℃; for 24h;

NH-pyrazole (288-13-1) + ethyl 2-bromoisobutyrate (600-00-0) → 4-bromo-1H-pyrazole (2075-45-8) + ethyl 2-(4-bromo-1H-pyrazol-1-yl)-2-methylpropanoate (1040377-17-0) + ethyl 3-(4-bromo-1H-pyrazol-1-yl)-2-methylpropanoate

Conditions	Yield
Stage #1: NH-pyrazole; ethyl 2-bromoisobutyrate With sodium t-butanolate In N,N-dimethyl-formamide Stage #2: With 1,3-dibromo-5,5-dimethylimidazolidine-2,4-dione

4-bromo-1H-pyrazole (2075-45-8) + ethyl vinyl ether (109-92-2) → 4-bromo-1-(1-ethoxyethyl)-1H-pyrazole (1024120-52-2)

Conditions	Yield
With hydrogenchloride In tetrahydrofuran; 1,4-dioxane at 20℃; for 3h;	100%
With hydrogenchloride In 1,4-dioxane; dichloromethane at 20℃; for 3h;	89%
With hydrogenchloride In 1,4-dioxane	89%

4-bromo-1H-pyrazole (2075-45-8) + 2-chloro-N-(2,4-dimethoxybenzyl)-5-nitrobenzenesulfonamide → 2-(4-bromo-1H-pyrazol-1-yl)-N-(2,4-dimethoxybenzyl)-5-nitrobenzenesulfonamide

Conditions	Yield
With potassium carbonate In acetonitrile at 100℃;	100%
With potassium carbonate In acetonitrile at 100℃;

4-bromo-1H-pyrazole (2075-45-8) + (2-trimethylethylsilylethoxy)methyl chloride (76513-69-4) → 4-bromo-1-<2-(trimethylsilyl)ethoxy>methyl-1H-pyrazole (133560-58-4)

Conditions	Yield
Stage #1: 4-bromo-1H-pyrazole With sodium hydride In tetrahydrofuran; mineral oil at 0℃; for 0.5h; Stage #2: (2-trimethylethylsilylethoxy)methyl chloride In tetrahydrofuran; mineral oil at 0 - 20℃; for 16h;	99%
Stage #1: 4-bromo-1H-pyrazole With sodium hydride In tetrahydrofuran; mineral oil at 0℃; for 0.5h; Stage #2: (2-trimethylethylsilylethoxy)methyl chloride In tetrahydrofuran; mineral oil at 20℃; for 16h;	99%
Stage #1: 4-bromo-1H-pyrazole With sodium hydride In tetrahydrofuran; mineral oil at 0 - 20℃; for 0.583333h; Stage #2: (2-trimethylethylsilylethoxy)methyl chloride In tetrahydrofuran; mineral oil at 0 - 20℃; for 16h;	91%

4-bromo-1H-pyrazole (2075-45-8) + trimethylamine-borane (75-22-9) → {1-(4-bromo)pyrazolyl}borane (16998-93-9)

Conditions	Yield
	99%
	99%

4-bromo-1H-pyrazole (2075-45-8) + chloro-methylsulfanyl-methane (2373-51-5) → 4-bromo-1-[(methylsulphanyl)methyl]-1H-pyrazole

Conditions	Yield
With potassium carbonate In acetonitrile at 100℃; for 16h;	99%
Stage #1: 4-bromo-1H-pyrazole With sodium hydride In N,N-dimethyl-formamide at 0 - 20℃; for 0.25h; Stage #2: chloro-methylsulfanyl-methane In N,N-dimethyl-formamide at 20℃;

4-bromo-1H-pyrazole (2075-45-8) + pentadeca-7,8-diene → (S,E)-4-bromo-1-(pentadec-8-en-7-yl)-1H-pyrazole

Conditions	Yield
With bis(η3-allyl-μ-chloropalladium(II)); (R)-segphos In toluene at 80℃; for 16h; Schlenk technique; Inert atmosphere; enantioselective reaction;	99%

4-bromo-1H-pyrazole (2075-45-8) + 3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione (58-08-2) → 4,5,8-tris(4-bromo-1H-pyrazol-1-yl)-1,3,7-trimethyl-3,4,5,7-tetrahydro-1H-purine-2,6-dione

Conditions	Yield
With tetrabutylammonium tetrafluoroborate In acetonitrile at 45℃; for 10h; Inert atmosphere; Electrochemical reaction; Green chemistry; diastereoselective reaction;	99%

4-bromo-1H-pyrazole (2075-45-8) + trityl chloride (76-83-5) → 4-bromo-1-trityl-1H-pyrazole (95162-14-4)

Conditions	Yield
With sodium hydride In tetrahydrofuran; mineral oil at 0 - 20℃; Inert atmosphere;	98.2%
With pyridine; dmap In dichloromethane at 20℃; for 16h;	96%
With potassium tert-butylate In N,N-dimethyl-formamide at 0 - 20℃; for 1h; Inert atmosphere;	89%

4-bromo-1H-pyrazole (2075-45-8) + p-toluenesulfonyl chloride (98-59-9) → 4-bromo-1H-pyrazol-1-yl(4-methylphenyl)sulfone (116228-41-2)

Conditions	Yield
With sodium hydroxide In dichloromethane at 20℃; for 24h;	98%
With sodium hydroxide In dichloromethane at 0 - 20℃;	98%
With triethylamine In dichloromethane at 20℃; for 3h;	73%
In pyridine for 2h; Heating;	70%
Stage #1: 4-bromo-1H-pyrazole With sodium hydride In tetrahydrofuran; mineral oil at 20℃; for 0.5h; Stage #2: p-toluenesulfonyl chloride In tetrahydrofuran; mineral oil at 20℃; for 12h;	63%

4-bromo-1H-pyrazole (2075-45-8) + 3-methanesulfonyloxy-azetidine-1-carboxylic acid tert-butyl ester (141699-58-3) → tert-butyl 3-(4-bromo-1H-pyrazol-1-yl)azetidine-1-carboxylate (877399-34-3)

Conditions	Yield
With sodium hydride In N,N-dimethyl-formamide at 110℃; for 0.5h; Microwave irradiation;	98%
With sodium hydride In N,N-dimethyl-formamide at 110℃; for 0.5h; Microwave irradiation;	98%
With sodium hydride In N,N-dimethyl-formamide; mineral oil at 110℃; for 0.5h; Inert atmosphere; Microwave irradiation;	98%

4-bromo-1H-pyrazole (2075-45-8) + 3-methoxycarbonylbenzyl bromide (1129-28-8) → 3-(4-bromo-pyrazol-1-ylmethyl)-benzoic acid methyl ester (1005628-24-9)

Conditions	Yield
With sodium carbonate In ISOPROPYLAMIDE at 60℃;	98%
Stage #1: 4-bromo-1H-pyrazole With sodium hexamethyldisilazane In tetrahydrofuran; N,N-dimethyl-formamide at 0℃; for 0.7h; Stage #2: 3-methoxycarbonylbenzyl bromide In tetrahydrofuran; N,N-dimethyl-formamide at 20℃;	79%

4-bromo-1H-pyrazole (2075-45-8) + 3-trifluoromethylaniline (98-16-8) → N-(3-trifluoromethylphenyl)-1H-pyrazol-4-amine (1537903-13-1)

Conditions	Yield
With t-BuBrettPhos; [(2-di-tert-butylphosphino-3,6-dimethoxy-2’,4’,6’-triisopropyl-1,1’-biphenyl)-2-(2’-amino-1,1‘-biphenyl)]palladium(II) methanesulfonate; lithium hexamethyldisilazane In tetrahydrofuran at 50℃; for 6h; Inert atmosphere; Sealed tube;	98%

4-bromo-1H-pyrazole (2075-45-8) + di-tert-butyl dicarbonate (24424-99-5) → 4-bromopyrazole-1-carboxylic acid tert-butyl ester (1150271-23-0)

Conditions	Yield
With dmap; triethylamine In acetonitrile at 20℃; for 2h;	98%
With triethylamine In dichloromethane at 20℃;	93%
In tetrahydrofuran at 30 - 45℃; Large scale;	92%

4-bromo-1H-pyrazole (2075-45-8) + 1-Hexadecene (629-73-2) → (S)-4-bromo-1-(hexadec-1-en-3-yl)-1H-pyrazole

Conditions	Yield
With chloro(1,5-cyclooctadiene)rhodium(I) dimer; JoSPOPhos SL-J688-2; pyridinium p-toluenesulfonate In toluene at 80℃; for 16h; Inert atmosphere; Schlenk technique; Sealed tube; enantioselective reaction;	98%

4-bromo-1H-pyrazole (2075-45-8) + p-methoxybenzyl chloride (824-94-2) → 4-bromo-1-(4-methoxybenzyl)-1H-pyrazole

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 20℃; for 14h;	98%

4-bromo-1H-pyrazole (2075-45-8) + 3-methoxy-1-iodobenzene (766-85-8) → 4-bromo-1-(3-methoxyphenyl)-1-hydropyrazole

Conditions	Yield
With copper(l) iodide; L-valine; potassium carbonate In dimethyl sulfoxide at 100℃; for 48h; Inert atmosphere;	98%
With copper(l) iodide; potassium carbonate; L-proline In dimethyl sulfoxide at 110℃; for 48h; Inert atmosphere;	89%
With copper(l) iodide; L-valine; potassium carbonate In dimethylsulfoxide-d6 at 110℃; for 48h;	89%

4-bromo-1H-pyrazole (2075-45-8) + pentacosa-12,13-diene → (S,E)-4-bromo-1-(pentacos-13-en-12-yl)-1H-pyrazole

Conditions	Yield
With bis(η3-allyl-μ-chloropalladium(II)); (R)-segphos In toluene at 80℃; for 16h; Schlenk technique; Inert atmosphere; enantioselective reaction;	98%

4-bromo-1H-pyrazole (2075-45-8) + copper(II) choride dihydrate + tetrabutyl-ammonium chloride (1112-67-0) → [N(n-C4H9)4]2[Cu3(μ3-Cl)2(μ-4-bromopyrazolato)3Cl3]

Conditions	Yield
With NaOH In dichloromethane byproducts: NaCl; stirring of equimolar amts. of CuCl2*2H2O, 4-bromopyrazole, NaOH and N(C4H9)4Cl in CH2Cl2 for 12 h at ambient temp.; filtration, treatment with Et2O, filtration, washing with Et2O, recrystn. from CH2Cl2/Et2O; elem. anal.;	97%

pyridin-3-ylamine (462-08-8) + 4-bromo-1H-pyrazole (2075-45-8) → N-(pyridin-3-yl)-1H-pyrazol-4-amine (1369433-25-9)

Conditions	Yield
With t-BuBrettPhos; [(2-di-tert-butylphosphino-3,6-dimethoxy-2’,4’,6’-triisopropyl-1,1’-biphenyl)-2-(2’-amino-1,1‘-biphenyl)]palladium(II) methanesulfonate; lithium hexamethyldisilazane In tetrahydrofuran at 80℃; for 6h; Inert atmosphere; Sealed tube;	97%

4-bromo-1H-pyrazole (2075-45-8) + 1-phenyl-2-bromoethane (103-63-9) → 4-bromo-1-(2-phenylethyl)pyrazole

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 25 - 90℃; for 14h;	97%
With potassium carbonate In acetonitrile at 90℃; for 12h;	70%

4-bromo-1H-pyrazole (2075-45-8) + hepta-3,4-diene-1,7-diyldibenzene (104367-27-3) → (S,E)-4-bromo-1-(tridec-7-en-6-yl)-1H-pyrazole

Conditions	Yield
With bis(η3-allyl-μ-chloropalladium(II)); (R)-segphos In toluene at 80℃; for 16h; Schlenk technique; Inert atmosphere; enantioselective reaction;	97%

4-bromo-1H-pyrazole (2075-45-8) + (1,2:5,6)-di-O-isopropylidene-D-gulose (14686-89-6) → 3-(4-bromo-1H-pyrazol-1-yl)-3-deoxy-1,2:5,6-di-O-isopropylidene-alpha-D-galactofuranose

Conditions	Yield
Stage #1: (1,2:5,6)-di-O-isopropylidene-D-gulose With pyridine; trifluoromethylsulfonic anhydride In dichloromethane at 0 - 10℃; for 1h; Stage #2: 4-bromo-1H-pyrazole With caesium carbonate In N,N-dimethyl-formamide for 18h; Cooling with ice;	97%

4-bromo-1H-pyrazole (2075-45-8) + aniline (62-53-3) → phenyl-(1H-pyrazol-4-yl)-amine

Conditions	Yield
With t-BuBrettPhos; [(2-di-tert-butylphosphino-3,6-dimethoxy-2’,4’,6’-triisopropyl-1,1’-biphenyl)-2-(2’-amino-1,1‘-biphenyl)]palladium(II) methanesulfonate; lithium hexamethyldisilazane In tetrahydrofuran at 50℃; for 6h; Inert atmosphere; Sealed tube;	96%
With sodium t-butanolate; tert-butyl XPhos; tris-(dibenzylideneacetone)dipalladium(0) In toluene at 110℃; for 24h;	94%

4-bromo-1H-pyrazole (2075-45-8) + ethyl iodide (75-03-6) → 1-ethyl-4-bromo-1H-pyrazole (71229-85-1)

Conditions	Yield
With tetra-(n-butyl)ammonium iodide; sodium hydroxide In water; dimethyl sulfoxide at 20℃;	96%
With potassium carbonate In N,N-dimethyl-formamide at 20℃; for 12h;	84%
With potassium carbonate In N,N-dimethyl-formamide at 20℃; for 12h;	84%

4-bromo-1H-pyrazole (2075-45-8) + 4-Fluorobenzyl bromide (459-46-1) → 4-bromo-1-(4-fluorobenzyl)-1H-pyrazole (251925-14-1)

Conditions	Yield
With potassium carbonate In acetone at 60℃; for 12h;	96%
Stage #1: 4-bromo-1H-pyrazole With sodium hydride In DMF (N,N-dimethyl-formamide) at 0℃; for 0.333333h; Stage #2: 4-Fluorobenzyl bromide In DMF (N,N-dimethyl-formamide) at 20℃; for 1h; Stage #3: With water In DMF (N,N-dimethyl-formamide) at 0℃;	86%

4-bromo-1H-pyrazole (2075-45-8) + 3-bromopropanol methyl ether (36865-41-5) → 4-bromo-1-(3-methoxypropyl)-1H-pyrazole (1183903-41-4)

Conditions	Yield
With caesium carbonate In N,N-dimethyl-formamide at 50℃;	96%
With caesium carbonate In N,N-dimethyl-formamide at 20℃; for 8h;	94%
With caesium carbonate In N,N-dimethyl-formamide at 50℃;

4-bromo-1H-pyrazole (2075-45-8) + 6-phenyl-1-hexene (1588-44-9) → (S)-4-bromo-1-(6-phenylhex-1-en-3-yl)-1H-pyrazole

Conditions	Yield
With chloro(1,5-cyclooctadiene)rhodium(I) dimer; JoSPOPhos SL-J688-2; pyridinium p-toluenesulfonate In toluene at 80℃; for 16h; Inert atmosphere; Schlenk technique; Sealed tube; enantioselective reaction;	96%

4-bromo-1H-pyrazole (2075-45-8) + 1-iodo-butane (542-69-8) → 4-bromo-1-butyl-1H-pyrazole (957062-61-2)

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 25℃; for 13h;	96%

4-bromo-1H-pyrazole (2075-45-8) + 6-methoxypyridine-3-ol (51834-97-0) → 2-(4-bromo-1H-pyrazol-1-yl)-6-methoxypyridin-3-ol

Conditions	Yield
With tert-butylammonium hexafluorophosphate(V) In dichloromethane at 23℃; Inert atmosphere; Electrochemical reaction;	96%

Upstream product

• 3112-31-0 3,5-pyrazoledicarboxylic acid 
• 288-13-1 NH-pyrazole 
• 13745-17-0 4-bromo-1H-pyrazole-3-carboxylic acid 
• 600-00-0 ethyl 2-bromoisobutyrate 
• 50901-46-7 Methyl 4-pyridazinyl ketone 

Downstream Products

• 37718-11-9 1H-pyrazole-4-carboxylic acid 
• 50901-46-7 Methyl 4-pyridazinyl ketone 
• 95162-14-4 4-bromo-1-trityl-1H-pyrazole 
• 857641-46-4 2-(4-bromo-1H-pyrazol-1-yl)pyrimidine 
• 15803-02-8 4-bromo-1-methyl-1H-pyrazole 
• 71229-85-1 4-bromo-1-ethyl-1H-pyrazole 
• 847818-54-6 2-(4-bromo-1H-pyrazol-1-yl)-N,N-dimethylethanamine 
• 141302-33-2 4-bromo-1-propyl-1H-pyrazole 
• 847818-48-8 4-bromo-1-(3-methylbutyl)-1H-pyrazole 
• 847818-49-9 4-bromo-1-(2-methoxyethyl)-1H-pyrazole 
• 50877-41-3 1-benzyl-4-bromo-1H-pyrazole 
• 35344-95-7 1H-pyrazole-4-carbaldehyde 
• 877399-67-2 [2-(4-bromo-pyrazol-1-yl)-ethyl]-methyl-carbamic acid tert-butyl ester 
• 877399-34-3 tert-butyl 3-(4-bromo-1H-pyrazol-1-yl)azetidine-1-carboxylate 

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