ChemicalBook >> CAS DataBase List >>Imidazole


Chemical Name:
Molecular Formula:
Lewis structure
c3h4n2 lewis structure
Molecular Weight:
MDL Number:
MOL File:
MSDS File:
Last updated:2024-05-11 20:10:50

Imidazole Properties

Melting point 88-91 °C(lit.)
Boiling point 256 °C(lit.)
Density 1.01 g/mL at 20 °C
vapor pressure <1 mm Hg ( 20 °C)
refractive index 1.4801
Flash point 293 °F
storage temp. Store below +30°C.
solubility H2O: 0.1 M at 20 °C, clear, colorless
form crystalline
pka 6.953(at 25℃)
Specific Gravity 1.03
color white
Odor Amine like
PH Range 9.5 - 11
PH 9.5-11.0 (25℃, 50mg/mL in H2O)
Water Solubility 633 g/L (20 ºC)
Sensitive Hygroscopic
λmax λ: 260 nm Amax: 0.10
λ: 280 nm Amax: 0.10
Merck 14,4912
BRN 103853
Dielectric constant 23.0(Ambient)
Stability Stable. Incompatible with acids, strong oxidizing agents. Protect from moisture.
LogP -0.02 at 25℃
CAS DataBase Reference 288-32-4(CAS DataBase Reference)
EWG's Food Scores 1
NIST Chemistry Reference 1H-Imidazole(288-32-4)
EPA Substance Registry System Imidazole (288-32-4)


Risk and Safety Statements

Symbol(GHS)  GHS hazard pictogramsGHS hazard pictogramsGHS hazard pictograms
Signal word  Danger
Hazard statements  H302-H314-H360D
Precautionary statements  P260-P280-P301+P312-P303+P361+P353-P304+P340+P310-P305+P351+P338
Hazard Codes  C,Xi,T
Risk Statements  36/38-63-34-22-20/21/22-61
Safety Statements  26-36/37/39-45-22-36-27-53
RIDADR  UN 2923 8/PG 3
WGK Germany  1
RTECS  NI3325000
Autoignition Temperature 480 °C
HazardClass  8
PackingGroup  III
HS Code  29332990
Toxicity LD50 in mice (mg/kg): 610 i.p.; 1880 orally (Nishie)
NFPA 704
3 0

Imidazole price More Price(144)

Manufacturer Product number Product description CAS number Packaging Price Updated Buy
Sigma-Aldrich RDD044 Imidazole ReagentPlus?, 99%, Redi-Dri?, free-flowing 288-32-4 100G $48.8 2024-03-01 Buy
Sigma-Aldrich RDD044 Imidazole ReagentPlus?, 99%, Redi-Dri?, free-flowing 288-32-4 500G $148 2024-03-01 Buy
Sigma-Aldrich RDD044 Imidazole ReagentPlus?, 99%, Redi-Dri?, free-flowing 288-32-4 1KG $262 2024-03-01 Buy
Sigma-Aldrich RDD044 Imidazole ReagentPlus?, 99%, Redi-Dri?, free-flowing 288-32-4 2.5KG $446 2024-03-01 Buy
Sigma-Aldrich RDD039 Imidazole for molecular biology, ≥99% (titration), free-flowing, Redi-Dri? 288-32-4 100G $721 2024-03-01 Buy
Product number Packaging Price Buy
RDD044 100G $48.8 Buy
RDD044 500G $148 Buy
RDD044 1KG $262 Buy
RDD044 2.5KG $446 Buy
RDD039 100G $721 Buy

Imidazole Chemical Properties,Uses,Production


Imidazole group denotes a heterocyclic organic compound whose molecule contains a five-membered hetero-aromatic ring of two non-adjacent nitrogen atoms, that a carbon atom is placed between two nitrogen atoms. Imidazole is the universally used trivial name for 1,3-azole. Earlier given names were glyoxaline and iminazole. The importance of this aromatic ring system is reflected by its presence in naturally occurring histidine, histamine and the purines, and in several classes of pharmaceuticals. Imidazole can act as a base and as a weak acid. It exists in two tautomeric forms with the hydrogen atom taking position between the two nitrogen atoms.

Chemical Properties

Imidazole is a moderately strong base (pKb= 7.0), and a weak acid (pKa= 14.9). Imidazoles substituted with electron-withdrawing groups are stronger acids than imidazole itself; e.g., 4(5)-nitroimidazole has a pKa of 9.3. Imidazole is stable at 400°C, possesses considerable aromatic character, and undergoes the usual electrophilic aromatic substitution reactions. Nitration and sulfonation require, however, far more drastic conditions than the corresponding reactions with benzene. Other substitution reactions of imidazole include halogenation, hydroxymethylation, coupling with aromatic diazonium salts, and carboxylation.


Imidazole[288-32-4] was first synthesized in 1858 by Debus from ammonia and glyoxal; it was originally named glyoxalin. The name imidazole was introduced by Hantzsch. Industrial production of imidazole began in the 1950s; a wide range of derivatives is now available in industrial quantities.


Imidazole is used as a buffer in the range of pH 6.2-7.8. It is also an histamine antagonist. It acts as a chelator and forms complexes with various divalent cations. It is used as a corrosion inhibitor on certain transition metals such as copper. Its derivatives, like polybenzimidazole (PBI), act as fire retardants. It finds application in photography and electronics. Imidazole salts are used as ionic liquids and precursors to stable carbenes. Imidazole derivatives like ketoconazole, miconazole and clotrimazole are involved in the treatment of various systemic fungal infections. It is a part of the theophylline molecule, present in tea leaves and coffee beans, which stimulates the central nervous system.


ChEBI: Imidazole is an imidazole tautomer which has the migrating hydrogen at position 1. It is a conjugate base of an imidazolium cation. It is a conjugate acid of an imidazolide. It is a tautomer of a 4H-imidazole. It is an important pharmacophore in drug discovery. Imidazole is used as a Karl Fischer reagent in analytical chemistry and a reagent in synthetic organic chemistry.


Imidazole is a versatile heterocycle used in the preparation of various biologically active compounds such as the amino acid histidine and is present in many antifungal medication. It is also used ext ensively as a corrosion inhibitor on transition metals such as copper.It is used in organic synthesis and as an antiirradiationagent.
Imidazole has been used:
in the lysis, wash and elution buffer for the purification of histidine tagged Sonic Hedgehog(shh-N) protein.
in elution buffer in stepwise gradient for the purification of histidine tagged aldo keto reductases using nickel affinity chromatography.
as a component of homogenization buffer for the purification of phagosomal compartments from dendritic cell.


Imidazole is formed by reacting glyoxal with formaldehyde in the presence of ammonium acetate in acetic acid. The driving energy is microwave radiation. More generally, this reaction is used to produce substituted imidazoles.
synthesis of Imidazole
Although there had been discoveries of various derivatives of imidazole in 1840, it was first reported in 1858. The synthesis process of imidazole follows the reaction between formaldehyde in ammonia and glyoxal. This process gives low yield of imidazole but it is still used to form imidazole with C-substitution (Wolkenberg et al., 2004).

General Description

Imidazole is a heterocyclic compound with a five-membered planar ring. It is amphoteric and highly polar. The pharmacophore of imidazole exists in bioactive compounds including amino acids, plant growth regulators and therapeutic agents.

Health Hazard

It is less toxic relative to pyrrole and otherfive-membered heterocyclic compounds ofnitrogen. Intraperitoneal administration ofimidazole caused somnolence, muscle contractions,and convulsions in mice. Theoral LD50 value in mice is in the range900 mg/kg.

Fire Hazard

Noncombustible solid.

Biochem/physiol Actions

Imidazole derivatives have antibacterial, antifungal and anticancer functionality. It interacts with DNA and also binds to protein and stops cell division. It also acts as a microtubule destabilizing agents and inhibits topoisomerase and Cytochrome P450 Family 26 Subfamily A Member 1 (CYP26A1) enzymes. Imidazole based anticancer drug find applications in cancer chemotherapy. It is used as buffer component for purification of the histidine tagged recombinant proteins in immobilized metal-affinity chromatography (IMAC).

Mechanism of action

N-substitution of imidazoles has created a family of drugs, called triazoles, that have the same mechanism of action as imidazoles, a similar or broader spectrum of activity, and less effect on human sterol synthesis. Both imidazoles and triazoles inhibit C-14α demethylation of lanosterol in fungi by binding to one of the cytochrome P-450 enzymes, which leads to the accumulation of C-14α methylsterols and reduced concentrations of ergosterol, a sterol essential for a normal fungal cytoplasmic membrane. Inhibition of cytochrome P-450 also decreases the synthesis of testosterone and glucocorticoids in mammals, an effect seen clinically with ketoconazole but not with later azoles[1].

Purification Methods

Crystallise imidazole from *benzene, CCl4, CH2Cl2, EtOH, pet ether, acetone/pet ether and distilled de-ionized water. Dry it at 40o under vacuum over P2O5. Distil it at low pressure. It is also purified by sublimation or by zone melting. [Snyder et al. Org Synth Coll Vol III 471 1955, Bredereck et al. Chem Ber 97 827 1964, Caswell & Spiro J Am Chem Soc 108 6470 1986.] 15N-imidazole crystallises from *benzene [Scholes et al. J Am Chem Soc 108 1660 1986]. [Beilstein 23 II 34, 23 III/IV 564, 23/4 V 191.]


[1] Rex, J. and D. Stevens. “39 – Drugs Active against Fungi, Pneumocystis, and Microsporidia.” Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases 23 1 (2015): 479-494.

Synthesis of Imidazole from N-BOC-IMIDAZOLE
Global( 1135)Suppliers
Supplier Tel Email Country ProdList Advantage
Aladdin Scientific
+1-833-552-7181 United States 57511 58
Anhui Royal Chemical Co., Ltd.
+86-25-86655873 +8613962173137 China 166 55
Shandong Believe Chemical PTE.LTD
+86-18553607090 +8618553607090 China 1682 58
Hebei Guanlang Biotechnology Co,.LTD
+8619930503252 China 5961 58
Hefei TNJ Chemical Industry Co.,Ltd.
0551-65418671 China 34572 58
Hebei Yanxi Chemical Co., Ltd.
+8617531190177 China 6011 58
Wuhan Quanjinci New Material Co.,Ltd.
+8615271838296 China 1534 58
Aladdin Scientific
+1-833-552-7181 United States 52927 58
Yancheng Green Chemicals Co.,Ltd
+undefined-86-25-86655873 China 114 58
Gansu Jinyuantai New Material Co., Ltd.
+86-025-86618065 +86-13914714331 China 73 58

Related articles

  • General Description of Imidazole
  • Imidazole is a planar, five-membered, unsaturated, 6π electron ring system, comprised of three carbon atoms and two nitrogen ....
  • Feb 11,2022

View Lastest Price from Imidazole manufacturers

Image Update time Product Price Min. Order Purity Supply Ability Manufacturer
Imidazole pictures 2024-05-24 Imidazole
US $6000.00 / kg 1000kg 99% 500 tons Changde Changlian Chemical Co., Ltd.
Imidazole pictures 2024-05-24 Imidazole
US $6000.00 / kg 1000kg 99% 500 tons Gansu Jinyuantai New Material Co., Ltd.
Imidazole pictures 2024-05-24 Imidazole
US $6000.00 / kg 1000kg 99% 500 tons Yancheng Green Chemicals Co.,Ltd
  • Imidazole pictures
  • Imidazole
  • US $6000.00 / kg
  • 99%
  • Changde Changlian Chemical Co., Ltd.
  • Imidazole pictures
  • Imidazole
  • US $6000.00 / kg
  • 99%
  • Gansu Jinyuantai New Material Co., Ltd.
  • Imidazole pictures
  • Imidazole
  • US $6000.00 / kg
  • 99%
  • Yancheng Green Chemicals Co.,Ltd
Imidazole [for Fluorimetric Analysis] Glyoxaline, lminazole IMIDAZOLE extrapure AR IMIDAZOLE pure IMIDAZOLEANALYTICAL GRADE IMIDAZOLERESEARCH GRADE Imidazole,1,3-Diaza-2,4-cyclopentadiene, Glyoxaline Ondansetron impurity E (Ph Eur) Ondansetron impurity E IMidazole 0.25 Crystallization solution 6/Fluka-Kit No 70437 Ondansetron EP Impurity E Imidazole anhydrous, free-flowing, Redi-Dri(TM), ACS reagent, >=99% Imidazole Vetec(TM) reagent grade, 98% R2 BROTH 2.5ML X 50 TUBES SAFRANIN O CERTIFIABLE GRADE SILICA GEL CHAMELEON C 1-3 MM SILICA GEL CHAMELEON C 2-6 MM SODIUM PHOSPHATE MONOBASIC ANHYD REAGENT Imidazole for Fluorometric Imidazole≥ 99% (GC) FINE ORGANIC COMPOUND , IMIDAZOLE DERIVA 1,3-Diazole Glyoxaline 1,3-diaza-2,4-cyclopentadiene n,n'-vinylene-formamidin Imidazole, ULTROL IMIDAZOLE BUFFER SOLUTION, 1M IN Imidazole Glyoxaline Imidazole, ULTROL Grade Imidazole, crystalline, 99+% IMIDAZOLE REAGENT (ACS) glyoxaline solution Imidazole, synthesis grade Imidazole, reagent grade, ACS Imidazole (200 mg) Imidazole (200 mg)G2E0311.00mg/mg(ai) Imidazole(flake,Crystal) IMIDAZOLE PH 7.0, 1.0 M SOLUTION* IMIDAZOLE, FOR MOLECULAR BIOLOGY IMIDAZOLE 99+% Imidazole, Reagent Grade IMIDAZOLE, 99+%, A.C.S. REAGENT IMIDAZOLE BUFFER SOLUTION, 1M IN WATER IMIDAZOLE R. G. IMIDAZOLE ACS REAGENT IMIDAZOLE, REAGENTPLUS, 99% IMIDAZOLE, FOR LUMINESCENCE IMIDAZOLE FOR FLUORESCENCE APPLICATIONS IMIDAZOLE, 4X10 G IMIDAZOLE MOLECULAR BIOLOGY REAGENT ImidazoleGr ImidazoleA.R. IMIDAZOLE GR (GLYOXALINE GR) 1,3-Diazole,1H-IMidazol IMIDAZOLE, 50 KG IMIDAZOLE FOR SYNTHESIS 250 G IMIDAZOLE FOR SYNTHESIS 5 G IMIDAZOLE FOR SYNTHESIS 25 KG IMIDAZOLE FOR SYNTHESIS 1 KG 1H-IMidazole (9CI)