Convenient Synthesis of 2,4-Diacetylphloroglucinol, a Natural Antibiotic Involved in the Control of Take-All Disease of Wheat

• Published in: Journal of agricultural and food chemistry 2000-05, Vol.48 (5), p.1882-1887
• Main Authors: Marchand, Patrice A, Weller, David M, Bonsall, Robert F
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - chemical synthesis; Anti-Bacterial Agents - therapeutic use; Phloroglucinol - analogs & derivatives; Phloroglucinol - chemical synthesis; Phloroglucinol - therapeutic use; Plant Diseases; Triticum
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf9907135

2,4-Diacetylphloroglucinol (DAPG) is an antibiotic with broad-spectrum antibacterial and antifungal activities. It is a major determinant in the biological control of several plant diseases. DAPG is produced by Pseudomonas fluorescens both in vitro and in the rhizosphere of wheat. It is involved in the natural suppression of take-all disease known as take-all decline, which develops in soils following extended monoculture of wheat or barley. A one-step synthesis of DAPG from the commercially available 2-acetylphloroglucinol is described. This reaction involves the direct alkylation of 2-acetylphloroglucinol using acetic anhydride as the acetylation reagent, with boron trifluoride−etherate as the catalyst. This synthesis is simple and produces higher yields of DAPG (90%) as compared with previously described procedures. As ecological concerns are gaining equal status with agricultural concerns, the demand for natural biocontrol measures is increasing. There is tremendous pressure from society on agriculture to reduce the use of pesticides. A discussion is given on the agricultural and ecological importance of this natural antibiotic and its application as an alternative to reduce the use of synthetic pesticides. Keywords: O-Acetylated; total intensity chromatogram (TIC); photodiodide array UV spectroscopy; high-pressure liquid chromotograpy (HPLC); mass spectrum (MS); retention time (RT); melting point (mp); phloroglucinol (Phl); 2-acetylphloroglucinol (MAPG); 2,4-diacetylphloroglucinol (DAPG); boron trifluoride−etherate; Pseudomonas fluorescens