The synthesis and characterization of a novel catalyticsystem including Pd(OAc)2 attached to a bis(oxazoline) (=BOX) ligand that is covalently bonded to 3-mercaptopropyl-functionalized silica gel is presented. The catalyst was tested for Suzuki–Miyaura reactions of different aryl halides with phenylboronic acid. The heterogeneity of the catalyticsystem was investigated using different approaches,
A new dimeric isocoumarin, bireticulol, was isolated from the terrestrial Streptomyces sp. and characterized as a 5-5â² dimer of reticulol. In addition, reticulol and 8-hydroxy-6,7-dimethoxy-3-methyl isocoumarin, together with other known polyketides piericidin A, 2â²-(2-hydroxyphenyl)-2,4â²-bibenzoxazole-4-carboxylic acid methyl ester (UK-1) and 3-benzyl-4-hydroxy-5-methyldihydrofuran-2-one were also obtained. Bireticulol exhibited cytotoxic effects against KB (human epidermoid carcinoma, ATCC CCL-17) and NCI-H187 (human small cell lung cancer, ATCC CRL-5804) cell lines with IC50 values of 24.4 and 8.31âμgâmlâ1, respectively.