A convenient, efficient and fast acetylation combining clays and ultrasound irradiation is described. Some molecules from nature or synthetic source, i.e., D-glucose, glycerol, D-mannitol and 1,2,3-triazolic derivatives such as N-glucosyl sugars and 2-substituted 1,4-naphthoquinone structures were acetylated. This kind of chemistry may be classified as eco-friendly because the reactions take a short time and the catalyst is reusable.

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Carbohydrates are the most abundant biomolecules that play crucial roles in many biological processes. In carbohydrate chemistry, the S-glycoside is an organic molecule in which sugar is bound to another functional group via a glycosidic bond. In the last few years, considerable progress has been made in the synthesis and applications of S-glycosides. Despite their challenging chemistry, S-glycosides play a pivotal role the development of the development of chemistry of biologically active molecules. This review, we report the natural occurrences, biosynthesis, different synthetic methodologies, proposed mechanisms and applications of S-glycosides. Os carboidratos são as biomoléculas mais abundantes que desempenham papéis fundamentais em muitos processos biológicos. Na química dos carboidratos, o S-glicosídeo é uma molécula orgânica na qual o açúcar é ligado a outro grupo funcional por meio de uma ligação glicosídica. Nos últimos anos, houve um avanço na síntese e aplicações de S-glicosídeos. Apesar de sua química desafiadora, os S-glicosídeos desempenham papel fundamental no desenvolvimento da química de moléculas biologicamente ativas. Nesta revisão, relatamos as ocorrências naturais, biossíntese, diferentes metodologias sintéticas, mecanismos propostos e aplicações de S-glicosídeos.

RECENT ADVANCES IN CHEMISTRY OF AMINO SUGARS: OCCURRENCE, BIOSYNTHESIS, SYNTHESIS AND APPLICATION. Amino sugars are chemical compounds that have a sugar backbone, in which one of the hydroxyl groups is replaced by an amino group. Derivatives of amine-containing sugars, such as N-acetylglucosamine, are also considered amino sugars. The synthetic introduction of amino functionalities in a regio-and stereoselective manner ontosugar scaffolds represents a substantial challenge. Most of the modern methods for the preparation of 1-, 2-and 3-amino sugars are those starting from glycals, 2,3-unsaturated O-glycosides epoxy-sugars, keto-sugars among others. This review summarizes recent developments in the current state of knowledge concerning the occurrence, biosynthesis, synthesis and application of amino sugars.