Neste trabalho é descrita a habilidade do SnCl 2 .2H 2 O como catalisador na reação de Biginelli tricomponente. Uma variedade de aldeídos aromáticos mono-e dissubstituidos foi utilizada na condensação com acetoacetato de etila e uréia ou tiouréia. A reação foi efetuada em etanol ou acetonitrila como solventes em meio neutro e os resultados representam um melhoramento com relação ao procedimento clássico de Biginelli e uma vantagem com relação ao uso de FeCl 3 .6H 2 O, NiCl 2 .6H 2 O e CoCl 2 .6H 2 O que são utilizados juntamente com HCl como co-catalisador. A síntese das 3,4-diidropirimidinonas foi conseguida em bons rendimentos.The ability of SnCl 2 .2H 2 O as catalyst to promote the Biginelli three-component condensation reaction from a diversity of aromatic aldehydes, ethyl acetoacetate and urea or thiourea is described. The reaction was carried out in acetonitrile or ethanol as solvents in neutral media and represents an improvement of the classical Biginelli protocol and an advantage in comparison with FeCl 3 .6H 2 O, NiCl 2 .6H 2 O and CoCl 2 .6H 2 O which were used with HCl as co-catalyst. The synthesis of 3,4-dihydropyrimidinones was achieved in good to excelent 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.

[reaction: see text] Contrasting and interesting electrochemical behavior is observed in anodic oxidation of N-substituted p-toluenesulfinamides under controlled current conditions. For sulfinamides derived from secondary alkylamines and primary arylamines, the N-sulfinyl group is removed and the corresponding amines are formed; for sulfinamides derived from primary alkylamines, sulfur oxidation yields the corresponding sulfonamides in good yields.

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Expeditious Synthesis of the Marine Natural Products Prepolycitrin A and Polycitrins A and B Through HeckArylations. -A concise synthesis of the marine natural product prepolycitrin A (I) and the total syntheses of the marine alkaloids polycitrins A (IIa) and B (IIb) in overall yields of 37% and 47%, respectively are reported. Heck-Matsuda arylation of maleic anhydride or dimethyl fumarate with aryldiazonium tetrafluoroborates followed by efficient bromination reactions provide access to the polycitrin family of compounds. -(CANTO, K.; DA SILVA RIBEIRO, R.; BIAJOLI, A. F. P.; CORREIA*, C. R. D.; Eur. J. Org. Chem. 2013, 35, 8004-8013, http://dx.