No abstract available

[en] The first chemical study of non-volatile constituents from the bark and stem of Melaleuca alternifolia (Myrtaceae) led to the isolation and identification of 3,3'-O-dimethylellagic acid (1) and five pentacyclic triterpenes: 2α,3β,23-trihydroxyolean-12-en-28-oic acid (arjunolic acid, 2), 3β-hydroxylup-20(29)-en-27,28-dioic acid (melaleucic acid, 3), betulinic acid (4), betuline (5), 3β-O-acetylurs-12-en-28-oic acid (6), a mixture of fatty acids and esters, and several hydrocarbons. For 2α,3β,23-trihydroxyolean-12-en-28-oic acid (2) and 3β-O-acetylurs-12-en-28-oic acid (6) a first detailed assignment of ¹H NMR is presented. (author)

No abstract available

[en] Considering the broad spectrum of biological activity of gamma-butyrolactone derivatives, we presented the synthesis of 3,4-dihalo-5-arylidenefuran-2(5H)-ones (17-21) and analogues (24-28) of the natural product nostoclide (7,8). Furanones 17-21 were synthesized from the condensation of aromatic aldehydes with lactones 14 and 15, that were obtained from mucobromic and mucochloric acids. Lactone 15 was converted into the intermediate 23 in 36% overall yield. Compound 23 was then transformed into the nostoclide analogues 24-28. Some of the compounds prepared showed antimicrobial activities against Escherichia coli, Staphylococcus aureus and Bacillus cereus comparable to commercial antibiotics. (author)