The prevalence of isocoumarins in numerous natural products that exhibit a wide range of biological activities has generated a continued and enormous interest among synthetic and medicinal chemists. The isocoumarin framework represents one of the privileged structures for the development of natural product-inspired compounds of potential biological interest. Considerable efforts have been devoted towards the synthesis of isocoumarins via either traditional or transition-metal catalyzed reactions. Among the metal catalyzed reactions, the use of Cu, Pd, Ag, Ru, Rh or Ir salts/complexes for the construction of isocoumarin ring are noteworthy. Among the other methodologies, halo-lactonization emerged as a practical process. Apart from preparing a variety of isocoumarins and thienopyranones, synthesis of naturally occurring and bioactive isocoumarins have been carried out by using cutting edge technologies. This review article will briefly cover all these aspects along with the synthetic utility of isocoumarins, highlighting recent developments.

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A number of pre-designed benzoxepine-1,2,3-triazole hybrids were synthesized for the first time using a Cu catalyzed azide-alkyne cycloaddition (CuAAC) strategy. Thus a 10

Descrevemos uma síntese rápida e pratica de pirazolonas, na ausência de solvente, sob irradiação de microondas. Esta metodologia sintética envolve a reação de b-cetoésteres com hidrazinas substituídas e não-substituídas e oferece uma preparação simples e direta de diferentes pirazolonas com alta regioseletividade. Essas pirazolonas podem existir em diferentes formas tautoméricas em solução e o anel 2-aril-pirazol-3-ona permanece torcido em relação ao plano da pirazolona no estado cristalino. O mecanismo da reação é proposto levando em conta a regiosseletividade. Uma das pirazolonas obtidas nesse processo foi usada na preparação de um derivado espirociclohexanona de significativo potencial biológico.A high speed, solvent-free, and practical synthesis of pyrazolones under microwave irradiation is described. This greener synthetic methodology involves the reaction of b-keto ester with substituted or unsubstituted hydrazine and provides a simple and straightforward one-pot approach for the synthesis of a variety of pyrazolone derivatives with high regioselectivity. These pyrazolones can exist in different tautomeric forms in solution and the aryl ring of 2-aryl pyrazol-3-ones remain twisted with respect to the pyrazole plane in the crystal state. Mechanism of the reaction accounting the regioselectivity has been proposed. One of the pyrazolones obtained via this process was utilized to prepare a spirocyclohexanone derivative of potential biological significance.

As modificações químicas da nimesulida via N-acilação direta ou através de um processo em duas etapas, envolvendo redução do grupo nitro seguida da acilação/sulfonilação regiosseletiva da arilamina resultante são descritas. A etapa da acilação do segundo método foi mais rápida do que a acilação da nimesulida. Uma série de derivados N-acilados e N-sulfonilados de N-(4-amino-2-fenóxi fenil)metanossulfonamida, obtidos a partir de nimesulida foram convenientemente preparados com bons a excelentes rendimentos. Alguns dos compostos sintetizados foram testados para inibição da ciclooxigenase e poucos mostraram seletividade para COX-2.We describe here the chemical modifications of nimesulide either via direct N-acylation or via a two-step process involving reduction of the nitro group followed by regioselective acylation/ sulfonylation of the resulting arylamine. The acylation step of the second approach was found to be faster than acylation of nimesulide. A number of N-acylated and N-sulfonylated derivatives of N-(4-amino-2-phenoxy phenyl)methanesulfonamide obtained from nimesulide were conveniently prepared in good to excellent yields. Some of the compounds synthesized were tested for cyclooxygenase inhibition and few of them showed selectivity for COX-2.