Van Urk reaction

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The Van Urk reaction is a wet chemical detection reaction for indoles named after the Dutch pharmacist Hendrik Willem van Urk with the help of the Van Urk reagent , a mixture of iron (III) chloride , sulfuric acid and dimethylaminobenzaldehyde . Indoles react with the Van Urk reagent to form a characteristic blue color, which can be used for photometric quantification and for thin-layer chromatographic detection.

Van-Urk reaction: main reaction of an indole with 4-dimethylaminobenzaldehyde

This reaction was originally developed in 1929 as evidence for ergot alkaloids . In its original version, it is based on a photochemical reaction of an ergot alkaloid with dimethylaminobenzaldehyde. Allport and Cocking added ferric chloride, which could speed up the reaction and make it independent of light. Numerous other variants of this reaction are described in the literature.

literature

  • HW van Urk: A new sensitive reaction for the ergot alkaloids, ergotamine, ergotoxine and ergotinine and its adaptation to the examination and colorimetric determination of ergot preparations . In: Pharm. Weekbl . 66, 1929, pp. 473-481.
  • Wolfgang Ax, Rudolf Hänsel, Josef Hölzl: Textbook of pharmaceutical biology: a textbook for students of pharmacy in the second phase of training . Springer, 1996, ISBN 3540589694 .
  • Ulf Pindur: 2, 2′ ‐ diindolylmethane, 7th report. Diindolylmethane leuco bases in the van Urk reaction with physiologically active indoles . In: Archives of Pharmacy . 317, No. 6, 1984, pp. 502-505.
  • Alexandr Jegorov: Analytical chemistry of ergot alkaloids . In: Vladimir Kren, Ladislav Cvak (eds.): Ergot: The Genus Claviceps. Medicinal and Aromatic Plants - Industrial Profiles . CRC Press, 2004, ISBN 0203304195 , pp. 267-303.