1-Chloro-2,4-dinitrobenzene

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**2,4-Dinitrochlorobenzene (DNCB)** is an organic compound with the chemical formula (O2N)2C6H3Cl. It is a yellow solid that is soluble in organic solvents. It is an important intermediate for the industrial production of other compounds.

DNCB is produced commercially by the nitration of *p*-nitrochlorobenzene with a mixture of nitric acid and sulfuric acid. Other methods afford the compound less efficiently include the chlorination of dinitrobenzene, nitration of o-nitrochlorobenzene and the dinitration of chlorobenzene.

**1-chloro-2,4-dinitrobenzene** is a C-nitro compound that is chlorobenzene carrying a nitro substituent at each of the 2- and 4-positions. It has a role as an epitope, an allergen and a sensitiser. It is a C-nitro compound and a member of monochlorobenzenes.

**Dinitrochlorobenzene** is an aromatic hydrocarbon composed of a benzene ring linked to two nitro groups and one chloride with potential use as an indicator for glutathione S-transferase (GST) activity, in the evaluation of T-cell immunocompetence, and as a treatment for warts. The chloride group of dinitrochlorobenzene (DNCB) is susceptible to nucleophilic substitution and is a target for GST-dependent glutathione conjugation in vitro; upon conjugation of the thiol group of glutathione to the DNCB substrate, there is an increase in the absorbance at 340 nm, which permits an indirect quantitation of GST activity in a sample. DNCB induces a type IV hypersensitivity reaction in most patients; therefore, exposure to DNCB can yield an indirect measurement of T-cell activity in a patient and immunocompromised patients may demonstrate decreased hypersensitivity toward DNCB. Following direct application to a wart, DNCB induces an allergic inflammatory response that may cure the viral infection that caused the wart.

## Appearance

Dinitrochlorobenzene appears as light yellowish crystals, it has a melting point at 54 °C.

## Uses

By virtue of the two nitro groups, the chloride is susceptible to nucleophilic substitution. In this way, the compound is a precursor to many other compounds. Base gives the dinitrophenol, ammonia the dinitroaniline, methoxide the dinitroanisole, and amines the secondary amines.

### Laboratory use

DNCB is used as a substrate in GST enzyme activity assays. The molecule is conjugated to a single molecule of reduced glutathione which then absorbs at 340 nm. Affinity of CDNB for each class of GST varies and so it is not a good measure of activity for some forms (e.g. GSTT and GSTZ).

### Medical use

DNCB can be used to treat warts with an effective cure rate of 80%. DNCB induces an allergic immune response toward the wart-causing virus.

## Safety

DNCB induces a type IV hypersensitivity reaction in almost all people exposed to it, so it is used medically to assess the T cell activity in patients. This is a useful diagnostic test for immunocompromised patients. It can also be used to treat warts.

DNCB can cause contact dermatitis.

## MolView Instructions

First, build a benzene figure with two positive-charged nitrogen atoms and one chlorine atom attached to the benzene figure, then add four oxygen atoms, two on each nitrogen, with one being double-bonded and one with a negative charge, and it should look like what is seen on the infobox.

## Trivia

* DNCB earns the NFPA 704 reactivity code 4, meaning it is very highly reactive.
* DNCB also is the first compound to contain multiple nitrogen atoms, all previous molecules with nitrogen only had one.
* DNCB is also the first compound to contain chlorine in it.
* DNCB is also the first compound to contain no hydrogen atoms being bonded to any elements other than carbon.

## External Links

1-Chloro-2,4-dinitrobenzene on MolView

1-Chloro-2,4-dinitrobenzene on PubChem

2,4-Dinitrochlorobenzene on Wikipedia