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Updated: Aug 10, 2026

Qualitative Identification of Carboxylic Acids, Boronic Acids, and Amines Using Cruciform Fluorophores
Published on: August 19, 2013
[Color reactions for identification of sodium cromoglycate]
K Görlitzer1, G Badia, P G Jones
1Institut für Pharmazeutische Chemie, Technischen Universität Braunschweig, Germany. k.goerlitzer@tu-bs.de
Abstract:
Chromone-2-carboxylic acid (3) reacts with aminopyrazolone (2) in methanolic hydrochloric acid to yield the orange-red polymethine dye 4. Treating dimethyl cromoglicate (6) with compound 2 and perchloric acid leads to the tetraperchlorate 7 of the red azamerocyanine 8. The phenol 9, obtained from alkaline hydrolysis of sodium cromoglicate (1a), couples with diazotized sulfanilic acid to form the red azo dye 10. The chromone 6 condenses with 1,3-dimethylbarbituric acid (DMBA) in acetic anhydride/acetic acid to the red oxonole 12. Cromoglicinic acid (1b) reacts under these conditions to yield the yellow polymethine dye 14, whose structure is elucidated by X-ray analysis.
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