Phenidone (1-phenyl-3-pyrazolidinone) is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

that is primarily used as a

photographic developer In the processing of photographic films, plates or papers, the photographic developer (or just developer) is one or more chemicals that convert the latent image to a visible image. Developing agents achieve this conversion by reducing the silve ...

. It has five to ten times the developing power as

Metol Metol (or Elon) is a trade name for the organic compound with the formula OC6H4NH2(CH3)SO4. It is the sulfate salt of ''N''-methylaminophenol. This colourless salt is a popular photographic developer used in black & white photography.Gerd Lö ...

. It also has low toxicity and unlike some other developers, does not cause

dermatitis Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved c ...

upon skin contact.''Merck Index of Chemicals and Drugs, 9th ed.'' monograph 7115 Phenidone is Ilford's trademark for this material, which was first prepared in 1890. It was not until 1940 that J. D. Kendall, in the laboratories of Ilford Limited, discovered the reducing properties of this compound. Large scale production did not become feasible until 1951.Karlheinz Keller et al. "Photography" in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2005, Wiley-VCH, Weinheim. Phenidone functions as a reducing agent. It converts to the ''N''-phenyl-hydroxypyrazole: PhenidoneAction

Preparation

Phenidone can be prepared by heating

phenyl hydrazine Phenylhydrazine is the chemical compound with the formula . It is often abbreviated as . It is also found in edible mushrooms. Properties Phenylhydrazine forms monoclinic prisms that melt to an oil around room temperature which may turn yellow ...

with 3-chloropropanoic acid.

References

{{Reflist Photographic chemicals Pyrazolidines Lactams Phenyl compounds