''para''-Dimethylaminobenzaldehyde is an organic compound containing

amine In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of elec ...

and

aldehyde In organic chemistry, an aldehyde () (lat. ''al''cohol ''dehyd''rogenatum, dehydrogenated alcohol) is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred ...

moieties which is used in

Ehrlich's reagent Ehrlich's reagent or Ehrlich reagent is a reagent containing ''p''-dimethylaminobenzaldehyde (DMAB) and thus can act as an indicator to presumptively identify indoles and urobilinogen. Several Ehrlich tests use the reagent in a medical test; so ...

and Kovac's reagent to test for

indoles Indole is an organic compound with the formula . Indole is classified as an aromatic Heterocyclic compound, heterocycle. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered pyrrole ring. Indoles are d ...

. The carbonyl group typically reacts with the electron rich 2-position of the indole but may also react at the C-3 or N-1 positions. It may also be used for determination of

hydrazine Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydraz ...

Ehrlich's reagent

''para''-Dimethylaminobenzaldehyde is the main ingredient in

. It acts as a strong electrophile which reacts with the electron-rich

α-carbon In the nomenclature of organic chemistry, a locant is a term to indicate the position of a functional group or substituent within a molecule. Numeric locants The International Union of Pure and Applied Chemistry (IUPAC) recommends the use of n ...

(2-position) of indole rings to form a blue-colored adduct. It can be used to detect the presence of

indole alkaloid Indole alkaloids are a class of alkaloids containing a structural moiety of indole; many indole alkaloids also include isoprene groups and are thus called terpene indole or secologanin tryptamine alkaloids. Containing more than 4100 known differ ...

s. Not all indole alkaloids give a colored adduct as result of

steric hindrance Steric effects arise from the spatial arrangement of atoms. When atoms come close together there is generally a rise in the energy of the molecule. Steric effects are nonbonding interactions that influence the shape ( conformation) and reactivi ...

which does not allow the reaction to proceed. Ehrlich's reagent is also used as a stain in

thin layer chromatography Thin-layer chromatography (TLC) is a chromatography technique that separates components in non-volatile mixtures. It is performed on a TLC plate made up of a non-reactive solid coated with a thin layer of adsorbent material. This is called the sta ...

and as a reagent to detect

urobilinogen Urobilinogen is a yellow by-product of bilirubin reduction. It is formed in the intestines by the bacterial enzyme bilirubin reductase. About half of the urobilinogen formed is reabsorbed and taken up via the portal vein to the liver, enters circu ...

in fresh, cool

urine Urine is a liquid by-product of metabolism in humans and many other animals. In placental mammals, urine flows from the Kidney (vertebrates), kidneys through the ureters to the urinary bladder and exits the urethra through the penile meatus (mal ...

. If a urine sample is left to

oxidize Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...

in air to form

urobilin Urobilin is the chemical primarily responsible for the yellow color of urine. It is a linear tetrapyrrole compound that, along with the related colorless compound urobilinogen, are degradation products of the cyclic tetrapyrrole heme. Metabolis ...

the

reagent In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...

will not detect the urobilinogen. By adding few drops of reagent to 3 mL of urine in a

test tube A test tube, also known as a culture tube or sample tube, is a common piece of laboratory glassware consisting of a finger-like length of glass or clear plastic tubing, open at the top and closed at the bottom. Test tubes are usually placed in s ...

one can see a change of color, to dark pink or red. The degree of color change is proportional to the amount of urobilinogen in the urine sample.

Hydrazine determination

''p''-Dimethylaminobenzaldehyde reacts with

to form ''p''-Dimethylaminobenzalazine

azo-dye Azo compounds are organic compounds bearing the functional group diazenyl (, in which R and R′ can be either aryl or alkyl groups). IUPAC defines azo compounds as: "Derivatives of diazene (diimide), , wherein both hydrogens are substituted b ...

which has a distinct yellow color. It is therefore used for

spectrophotometric Spectrophotometry is a branch of electromagnetic spectroscopy concerned with the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. Spectrophotometry uses photometers, known as spe ...

determination of hydrazine in aqueous solutions at 457 nm.

Isaac Asimov essay

Isaac Asimov Isaac Asimov ( ; – April 6, 1992) was an Russian-born American writer and professor of biochemistry at Boston University. During his lifetime, Asimov was considered one of the "Big Three" science fiction writers, along with Robert A. H ...

, in a 1963 humorous essay entitled "You, too, can speak Gaelic", reprinted in the anthology ''

Adding a Dimension ''Adding a Dimension'' is a collection of seventeen scientific essays by American writer and scientist Isaac Asimov. It was the third of a series of books collecting essays from ''The Magazine of Fantasy and Science Fiction''. It was first publ ...

'' among others, traces the

etymology Etymology ( ) is the study of the origin and evolution of words—including their constituent units of sound and meaning—across time. In the 21st century a subfield within linguistics, etymology has become a more rigorously scientific study. ...

of each component of the chemical name "para-di-methyl-amino-benz-alde-hyde" (e.g. the syllable "-benz-" ultimately derives from the Arabic lubān jāwī (لبان جاوي, "

frankincense Frankincense, also known as olibanum (), is an Aroma compound, aromatic resin used in incense and perfumes, obtained from trees of the genus ''Boswellia'' in the family (biology), family Burseraceae. The word is from Old French ('high-quality in ...

from

Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...

"). Asimov points out that the name can be pronounced to the tune of the familiar

jig The jig (, ) is a form of lively folk dance in compound metre, as well as the accompanying dance tune. It first gained popularity in 16th-century England, Ireland, Scotland, and other parts of the British Isles, and was adopted on mainland Eu ...

The Irish Washerwoman "The Irish Washerwoman" is a traditional jig known to have been played throughout Britain and Ireland and in North America. Although usually considered an Irish tune, some scholars claim that it is English in origin, derived from the seventeenth-c ...

", and relates an anecdote in which a receptionist of Irish descent, hearing him singing the syllables thus, mistook them for the original

Gaelic Gaelic (pronounced for Irish Gaelic and for Scots Gaelic) is an adjective that means "pertaining to the Gaels". It may refer to: Languages * Gaelic languages or Goidelic languages, a linguistic group that is one of the two branches of the Insul ...

words to the jig. This essay inspired Jack Carroll's 1963

filk Filk music is a musical culture, genre, and community tied to science fiction, fantasy, and horror fandom and a type of fan labor. The genre has existed since the early 1950s and been played primarily since the mid-1970s. The genre has a ni ...

song "The Chemist's Drinking Song," (

NESFA The New England Science Fiction Association, or NESFA, is a science fiction club centered in the New England area. It was founded in 1967, "by fans who wanted to ''do'' things in addition to socializing". NESFA is currently registered as a non- ...

Hymnal Vol. 2 2nd ed. p. 65) set to the tune of that jig, which begins "Paradimethylaminobenzaldehyde, /

Sodium citrate Sodium citrate may refer to any of the sodium salts of citric acid (though most commonly the third): * Monosodium citrate * Disodium citrate * Trisodium citrate The three forms of salt are collectively known by the E number E331. Applications ...

ammonium cyanide Ammonium cyanide is an unstable inorganic compound with the chemical formula . It is the ammonium salt of hydrogen cyanide. It consists of ammonium cations and cyanide anions . Its structural formula is . Uses Ammonium cyanide is generally used ...

, / ..."

References

{{DEFAULTSORT:Dimethylaminobenzaldehyde, Para- Urine Chemical tests Benzaldehydes Dimethylamino compounds Analytical chemistry

Ehrlich's reagent

Hydrazine determination

Isaac Asimov essay

See also

References