Pogostone
Pogostone or dhelwangin is a naturally occurring organic compound with the formula C12H16O4. Classified as a secondary metabolite, primarily found in patchouli, a member of the mint family Lamiaceae. This plant has historically been used in traditional Chinese medicine to treat ailments such as the common cold, nausea, diarrhea, headache, and fever, and is also applied for its antifungal properties. Pogostone was first identified in 1969 as the major antimicrobial constituent of Pogostemonis Herba, the dried aerial parts of patchouli used in herbal preparations.
Structure and properties
Pogostone has the molecular formula C12H16O4. Pogostone was obtained as needle-like colorless crystals. Its melting point was reported as 32–33 °C. It features a 2H-pyranone core and was first structurally characterized by X-ray crystallography, which also revealed the presence of intramolecular hydrogen bonding.Due to its low natural abundance in the plant, synthetic methods for pogostone production have been developed. One synthetic route involves the condensation of dehydroacetic acid with aldehydes in dry tetrahydrofuran under nitrogen at low temperature, followed by hydrogenation, chromatography, and crystallization. The reaction proceeds via deprotonation, Michael addition reaction, tautomerization, and further deprotonation steps. Two diastereomeric dimers of pogostone, with and configurations, have also been synthesized and structurally confirmed by nuclear magnetic resonance and X-ray diffraction.