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

amine In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen Hydrogen is the chemical element wi ...

and

aldehyde In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl grou ...

moieties which is used in Ehrlich's reagent and Kovac's reagent to test for

indoles Indole is an aromatic heterocyclic organic compound with the formula C8 H7 N. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered pyrrole ring. Indole is widely distributed in the natural environment ...

. 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.

Ehrlich's reagent

''para''-Dimethylaminobenzaldehyde is the main ingredient in Ehrlich's reagent. It acts as a strong electrophile which reacts with the electron-rich α-carbon (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 diffe ...

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 a rise in the energy of the molecule. Steric effects are nonbonding interactions that influence the shape ( conformation) and reactivity of ions ...

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 used to separate non-volatile mixtures. Thin-layer chromatography is performed on a sheet of an inert substrate such as glass, plastic, or aluminium foil, which is coated with a t ...

and as a reagent to detect

urobilinogen Urobilinogen is a colorless by-product of bilirubin reduction. It is formed in the intestines by bacterial action on bilirubin. About half of the urobilinogen formed is reabsorbed and taken up via the portal vein to the liver, enters circulation an ...

in fresh, cool

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellular ...

. If a urine sample is left to

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

in air to form

urobilin Urobilin or urochrome 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 ...

the reagent 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 ...

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 hydrazine to form ''p''-Dimethylaminobenzalazine azo-dye which has a distinct yellow color. It is therefore used for spectrophotometric determination of hydrazine in aqueous solutions at 457 nm.

Isaac Asimov essay

Isaac Asimov, 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 ()The New Oxford Dictionary of English (1998) – p. 633 "Etymology /ˌɛtɪˈmɒlədʒi/ the study of the class in words and the way their meanings have changed throughout time". is the study of the history of the Phonological chan ...

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 from

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mos ...

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

jig The jig ( ga, port, gd, port-cruinn) is a form of lively folk dance in compound metre, as well as the accompanying dance tune. It is most associated with Irish music and dance. It first gained popularity in 16th-century Ireland and parts of ...

" The Irish Washerwoman", and relates an anecdote in which a receptionist of Irish descent, hearing him singing the syllables thus, mistook them for the original Gaelic 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. Etymology and defi ...

song "The Chemist's Drinking Song," ( NESFA 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 formula NH4CN. Uses Ammonium cyanide is generally used in organic synthesis. Being unstable, it is not shipped or sold commercially. Preparation Ammonium cyanide is prepared in solutio ...

, / ..."

References

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

Ehrlich's reagent

Hydrazine determination

Isaac Asimov essay

See also

References