Tropic acid explained

Tropic acid is a chemical with IUPAC name 3-hydroxy-2-phenylpropanoic acid and condensed structural formula HOCH₂CHPhCOOH. It is a laboratory reagent used in the chemical synthesis of atropine and hyoscyamine. Tropic acid is a chiral substance, existing as either a racemic mixture or as a single enantiomer.

Synthesis

Tropic acid can be prepared by the Ivanov reaction between phenylacetic acid and formaldehyde. In this method, the dianion of the acid is formed using a Grignard reagent, isopropyl magnesium chloride, and this reacts with the aldehyde to form the magnesium salt of the product, from which the pure acid is obtained after acidification with sulfuric acid.^[1]

Many other methods have been used to make tropic acid, for example starting from acetophenone (1).^[2]

Uses

Tropic acid is used in the chemical synthesis of atropine and hyoscyamine.^[1]

Notes and References

1. 10.1021/ja01121a504 . free . The Preparation of Tropic Acid . 1952 . Blicke . F. F. . Raffelson . Harold . Barna . Bohdan . Journal of the American Chemical Society . 74 . 253 .
2. 12365608 . 2002. Gadzikowska. M. Tropane alkaloids in pharmaceutical and phytochemical analysis. Acta Poloniae Pharmaceutica. 59. 2. 149–60. Grynkiewicz. G.