Phloroglucin derivatives

Another common plant that appears to have some activity against MRSA is Hypericum perforatum L., commonly known as St. John s wort. In traditional folk medicine, oily extracts of St. John s wort are used for topical treatment of wounds, bums and myalgia [39]. The lipophilic phloroglucin-derivative hyperforin. Fig. 3, has antibacterial effects and has been shown to inhibit the growth of MRSA at a concentration of 1 (ig/ml [39]. Thus, investigating known plants based on their historical medical (ethnomedical) use is a potentially useful means of discovering new alternative antimicrobial agents. 

Lee, S. H., Li, Y., Karadeniz, F., Kim, M. M., and Kim, S. (2009). a-Glucosidase and a-amylase inhibitory activities of phloroglucinal derivatives from edible marine brown alga, Ecklonia cava.. Sci. Food Agric. 89,1552-1558. 

Bohlmann, F., and C. Zdero Neue phloroglucin—derivate aus Helichrysum natalitium und Helichrysum bellum. Phytochem. 18. 641 (1979). 

Nitro-Derivatives of Aryl-N-hydroxylamine 6-Nitro-2,4-Dihydroxy lamino-phloroglucinol (called -phloroglucin in Ger). (H0)3C6(N02) (NHOH)2 mw 233.14, N 18.03%, OB -58.5% yellowish needles, mp 166° (decomp) has similar props and same meth of prep as the dinitro derivative described below... 

The Simonis chromone synthesis was reported as a key reaction in the preparation of the natural product visnagin 48, a component found in fruits. Badawi and Fayez reported the conversion of 44 and 46 using heat in diphenyl ether in satisfactory yield. The aldehydic product 47 was derived from phloroglucin aldehyde 45 via similar thermal reaction conditions and was subsequently converted into visnagin 48. Note that the cyclization occurred under thermal conditions with no acid catalysis. 

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