Indazole, also called isoindazole, is a
heterocyclic aromatic
In organic chemistry, aromaticity is a chemical property describing the way in which a conjugated system, conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibits a stabilization stronger than would be expected from conjugati ...
organic compound
Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...
. This
bicyclic
A bicyclic molecule () is a molecule that features two joined rings. Bicyclic structures occur widely, for example in many biologically important molecules like α-thujene and camphor. A bicyclic compound can be carbocyclic (all of the ring ...
compound consists of the fusion of
benzene
Benzene is an Organic compound, organic chemical compound with the Chemical formula#Molecular formula, molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar hexagonal Ring (chemistry), ring with one hyd ...
and
pyrazole
Pyrazole is an organic compound with the chemical formula, formula . It is a heterocycle characterized as an azole with a 5-membered ring of three carbon atoms and two adjacent nitrogen atoms, which are in Arene substitution pattern, ortho-substi ...
.
Indazole is an
amphoteric molecule which can be protonated to an indazolium cation or deprotonated to an indazolate anion. The corresponding ''pKa'' values are 1.04 for the equilibrium between indazolium cation and indazole and 13.86 for the equilibrium between indazole and indazolate anion.
Indazole derivatives display a broad variety of biological activities.
Indazoles are rare in nature. The
alkaloid
Alkaloids are a broad class of natural product, naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids.
Alkaloids are produced by a large varie ...
s
nigellicine,
nigeglanine, and
nigellidine are indazoles. Nigellicine was isolated from the widely distributed plant ''
Nigella sativa'' L. (black cumin). Nigeglanine was isolated from extracts of ''
Nigella glandulifera''.
The
Davis–Beirut reaction can generate 2''H''-indazoles.
Indazole, C
7H
6N
2, was obtained by E. Fischer (''Ann.'' 1883, 221,
p. 280) by heating ortho-hydrazine cinnamic acid,
:

Drugs made from Indazole
Benzydamine, commonly branded as Tantum Verde and Difflam, is the most well known Indazole derivative. It is a
nonsteroidal anti-inflammatory, with local
anaesthetic and
analgesic
An analgesic drug, also called simply an analgesic, antalgic, pain reliever, or painkiller, is any member of the group of drugs used for pain management. Analgesics are conceptually distinct from anesthetics, which temporarily reduce, and in s ...
properties for
pain relief and
anti-inflammatory
Anti-inflammatory is the property of a substance or treatment that reduces inflammation, fever or swelling. Anti-inflammatory drugs, also called anti-inflammatories, make up about half of analgesics. These drugs reduce pain by inhibiting mechan ...
treatment of
inflammatory conditions of the
mouth
A mouth also referred to as the oral is the body orifice through which many animals ingest food and animal communication#Auditory, vocalize. The body cavity immediately behind the mouth opening, known as the oral cavity (or in Latin), is also t ...
and
throat
In vertebrate anatomy, the throat is the front part of the neck, internally positioned in front of the vertebrae. It contains the Human pharynx, pharynx and larynx. An important section of it is the epiglottis, separating the esophagus from the t ...
.
See also
*
Indole
Indole is an organic compound with the formula . Indole is classified as an aromatic heterocycle. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered pyrrole ring. Indoles are derivatives of indole ...
, an analog with only one
nitrogen
Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...
atom
Atoms are the basic particles of the chemical elements. An atom consists of a atomic nucleus, nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished fr ...
in position 1.
*
Benzimidazole
Benzimidazole is a heterocyclic aromatic organic compound. This bicyclic compound may be viewed as fused rings of the aromatic compounds benzene and imidazole. It is a white solid that appears in form of tabular crystals.
Preparation
Benzimi ...
, an analog with the nitrogen atoms in positions 1 and 3.
*
Simple aromatic rings
*
7-Nitroindazole, an indazole-based
nitric oxide synthase inhibitor
References
* Synthesis:
* Review:
{{Nitric oxide signaling
Simple aromatic rings