Valéria Belli Riatto

Universidade Federal da Bahia · Departamento de Química Orgânica

To research the potential ability of whole marine sponges to act as biocatalysts, this paper describes for the first time the employment of whole Cliona varians sponge in the stereoselective reduction of prochiral α-keto esters and isatin to the corresponding chiral alcohols. The addition of D-fructose, D-glucose or sucrose remarkably increased the...

This work proposes an on-line preconcentration system using ion-imprinted polymer (IIP) for determination of bismuth in seawater employing atomic fluorescence spectrometry (AFS). The polymer was synthesized using 2- (5-bromo-2-pyridylazo) -5-diethylaminophenol (Br-PADAP) for complex formation, ethylene glycol dimethacrylate (EGDMA), cross-linking r...

The semiarid region in northeastern Brazil covers 735,000 km², and it comprises different vegetation types under a dry tropical climate. This is one of the most populated and biologically diverse semiarid regions in the world. Due to adverse climatic conditions and low incomes, this region has historically concentrates the majority of rural poverty...

In this work, an undergraduate organic chemistry experiment based on thermal cracking of glycerin is proposed. The reagent is obtained as a by-product from the practice of biodiesel synthesis, and allows reduction of waste produced in the lab. The main product obtained from thermal cracking was characterized by GC analysis as acrolein. This substan...

This work describes a green chemistry experiment for the synthesis of Erlenmeyer-Plöchl azalactones mediated by microwave irradiation, employing both dedicated and domestic equipment. Hippuric acid was reacted with equimolar amounts of benzaldehyde, p-chloro-benzaldehyde or p-N,N-dimethyl-benzaldehyde in acetic anhydride as the solvent. Acid hydrol...

The maturity of the National Institute of Science and Technology in Energy and Environment (INCT E&A) to act in a complex and articulated way in all areas of science is portrayed in this article. Several extra-laboratory activities in the fields of education, extension, and popularization of science are shown. This commitment is exemplified by "The...

The selective reduction of dimethyl 3-oxoglutarate was accomplished in different levels. A high yielding sodium borohydride reduction of the keto group is fully described leading to dimethyl 3-hydroxyglutarate. When borane-dimethyl sulfide (BMS) complex was used, a diol or a triol compound can be obtained by selective or total reduction of 3-hydrox...

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O curso estereoquímico da adição de enolatos de titânio quirais a -lactóis derivados do ácido (S)-glutâmico foi investigado. Quando -lactóis 5-substituídos foram tratados com enolatos de titânio quirais derivados de N-acetil-, N-propionil-, N-bromoacetil-e N-fenilacetil oxazolidin-2-onas somente dois diastereoisômeros foram obtidos, revelando um co...

5-Substituted lactol 1 was converted to 2,5-disubstituted tetrahydrofuran derivatives by a Lewis acid-promoted reaction with allylsilanes. High trans selectivity (12:1) was obtained when hindered allylsilane 8 was employed. 5-Substituted lactol 16 was transformed into 2,5-cis-disubstituted tetrahydrofuran 17b (6:1 ratio) by a TiCl4-promoted intramo...

[GRAPHICS] The addition of the titanium enolates of N-acetyl, N-propionyl, and N-bromoacetyl (R)-oxazolidin-2-ones to gamma-lactol 2, derived from (S)-glutamic acid, afforded trans- and cis-2,5-disubstituted tetrahydrofurans (trans/cis ratio: R = H, 2:1; R = Me, 8:1; R = Br, 10:1) after desilylation with aqueous HF/CH3CN, Chromatographic separation...

[reaction: see text] The addition of the titanium enolates of N-acetyl, N-propionyl, and N-bromoacetyl (R)-oxazolidin-2-ones to gamma-lactol 2, derived from (S)-glutamic acid, afforded trans- and cis-2,5-disubstituted tetrahydrofurans (trans/cis ratio: R = H, 2:1; R = Me, 8:1; R = Br, 10:1) after desilylation with aqueous HF/CH3CN. Chromatographic...

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...

The asymmetric synthesis of (+)-sitophilure, the aggregation pheromone of Sitophilus oryzae L. and Sitophilus zeamais M., was carried out in 12 steps, 18% overall yield and 82% enantiomeric excess from the enzymatic reduction of methyl 3-oxopentanoate with S. cerevisiae in the presence of ethyl chloroacetate.

A short and efficient preparation of enantiomerically enriched (80% ee) (-)-serricornine (1), the sex pheromone of the cigarette beetle Lasioderma serricorne F., was developed in 8 steps and 13% overall yield from methyl (R)-3-hydroxypentanoate readily prepared by baker's yeast reduction of methyl 3-oxopentanoate in the presence of allyl alcohol as...

Dechlorination reactions of exo-endo and endo-endo perhalogenated tetracyclic compounds with Li/t-BuOH/THF system, when subjected to simultaneous ultra-sound irradiation, led to exceptionally high yields (77-95%) of the corresponding hydrocarbons.