[1] A few years later Asano and Yosio Arata further purified the crude material from this lichen, ultimately obtaining an orange-yellow compound with a molecular formula of C16H12O6.

[2] In 1949, T. R. Seshadri and S. Subramanian published their investigations into the chemistry of Teloschistes flavicans,[3] a lichen from which they isolated an orange substance they named teloschistin, and which had a structural formula identical to that of fallacin proposed by Asano and Arata years earlier.

[5] In an early chemical examination of the lichen Teloschistes flavicans, Friedrich Wilhelm Zopf identified two substances: physcion (now known more commonly as parietin) with a melting point (m.p.)

[6] The presence of another compound with a higher melting point posed a purification challenge, which was resolved by employing petroleum ether and chloroform for sequential extraction.

They confirmed its molecular formula as C16H12O6 and identified it as a hydroxyl derivative of parietin, lacking specific hydroxy groupings that would typically cause fluorescence or colour changes in acidic conditions.

[7] The research also noted the slower-than-expected reaction rates during oxidation, suggesting a distinctive reactivity pattern for fallacinol, possibly due to its additional hydroxyl group.

Similar to parietin, it produces a reddish-brown colour with alcoholic ferric chloride and yields a deep orange-red solution with concentrated sulfuric acid, which appears eosin-like in thin layers.

To early researchers, these properties suggested that fallacinol was structurally similar to parietin but with an additional oxygen atom, inferred to be a hydroxyl group, based on its higher melting point and reduced solubility.

The sparing solubility of its potassium salt and its insolubility in aqueous sodium carbonate suggested a methoxyl group placement consistent with other known compounds like parietin and erythroglaucin.

This reduced form can be prepared by treating fallacinol with zinc dust in boiling acetic acid, yielding lemon-yellow prismatic crystals with a melting point of 249–250 °C.

[9][10] In a study exploring lichen compounds for COVID-19 therapeutics, fallacinol demonstrated the highest binding energy against SARS-CoV-2's spike protein, suggesting its potential as an inhibitor of virus growth.

The process involves the conversion of parietin diacetate to an ω-bromo derivative via N-bromosuccinimide in the presence of benzoyl peroxide, a technique also applied to various anthraquinones and related compounds.

[15] Fallacinol is a common secondary metabolite in the lichen genus Teloschistes, typically occurring in smaller amounts alongside parietin and other related compounds like fallacinal and emodin.