Isolation and structure determination of γ-pyrufuran, a third induced antifungal dibenzofuran from the wood of Pyrus communis L. infected with Chondrostereum purpureum(Pers. ex Fr.) Pouzar

Abstract

The induced antifungal compound γ-pyrufuran has been isolated from the wood of perry pear trees [Pyrus communis L. (Rosaceae) cv. Thorn.] infected with Chondrostereum purpureum(Pers. ex Fr.) Pouzar. Spectroscopic and chemical evidence indicate that the compound is one of four 1,2,3,4,7-substituted trimethoxydibenzofurandiols in which one hydroxy group occupies the 7-position. Selective reduction of the dimesylated derivative by hydrogen with a Pd–C catalyst, followed by base-catalysed hydrolysis, produced α-pyrufuran (1,3,4-trimethoxydibenzofuran-2-ol)(6), and shows γ-pyrufuran to be 1,3,4-trimethoxydibenzofuran-2,7-diol (1).