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Aryldiazonium tetrafluoroborates have been successfully employed in the direct and regioselective arylation of heteroaromatics such as indole, benzofuran and benzothiophene. The cationic aryl palladium intermediates derived from the aryldiazonium salts act as effective electrophiles in the process. These arylating reactions display operational simplicity and provide the arylated heterocycles regioselectively in moderate to excellent yields.

New, efficient protocols for the syntheses of the marine natural products prepolycitrin A as well as polycitrins A and B were developed by employing the Heck–Matsuda arylation of maleic anhydride or dimethyl fumarate with aryldiazonium tetrafluoroborates. Both symmetrical and unsymmetrical 3,4‐diarylmaleic anhydrides were easily and effectively prepared. Efficient bromination reactions that employed tribromoisocyanuric acid provided access to the polycitrin family of compounds. Under microwave irradiation in the presence of tyramine, the corresponding maleimides were obtained in high yields from the brominated 3,4‐diarylmaleic anhydrides. This methodology provided for the concise synthesis of prepolycitrin A and the total syntheses of the marine alkaloids polycitrins A and B in overall yields of 37 and 47 % from maleic anhydride and dimethyl fumarate, respectively.

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The preparation and applicability of solid phase microextraction (SPME) fibers coated with a sol-gel organically modified silica based on 3-aminopropyltrimethoxysilane and polydimethylsiloxane (APTMS/PDMS) are described here. Micrographs of the coated fibers revealed a rugous surface; the thickness of the coating was estimated to be less than 30 mm. The APTMS/PDMS fibers were tested with synthetic samples and compared to commercial fibers for headspace SPME analysis of beer. Extraction and desorption using the APTMS/PDMS fibers were faster, which is typical for sol-gel SPME fibers. For polar and semi-polar compounds on beer headspace, the extraction efficiencies of the APTMS/PDMS fiber were superior to those of conventional fibers. The APTMS/PDMS fiber was found to be capable of extracting a broad range of analytes, including highly polar acidic species such as organic acids.

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