Chiral Pharmaceutical Intermediaries Obtained by Reduction of 2-Halo-1-(4-substituted phenyl)-ethanones Mediated by Geotrichum candidum CCT 1205 and Rhodotorula glutinis CCT 2182

Enantioselective reductions of p-R1-C6H4C(O)CH2R2 (R1 = Cl, Br, CH3, OCH3, NO2 and R2 = Br, Cl) mediated by Geotrichum candidum CCT 1205 and Rhodotorula glutinis CCT 2182 afforded the corresponding halohydrins with complementary R and S configurations, respectively, in excellent yield and enantiomeric excesses. The obtained (R)- or (S)-halohydrins are important building blocks in chemical and pharmaceutical industries

Acylsilanes and their applications in organic chemistry

Current studies concerning the use of acylsilanes in a variety of organic synthetic routes and the improved methodologies of their preparation have turned organosilanes into important reagents for organic chemistry. This review discusses the recent employment of acylsilanes in organic synthesis and also effective methods for their preparation.Estudos sobre o emprego de acilsilanos em rotas sintéticas e as novas metodologias de preparação desenvolvidas nos últimos anos, tornaram estes organo-silanos importantes reagentes para síntese de compostos orgânicos. Esta revisão apresenta algumas aplicações recentes e vários métodos desenvolvidos para síntese de acilsilanos.073

Effect Of Immobilized Cells In Calcium Alginate Beads In Alcoholic Fermentation.

Saccharomyces cerevisiae cells were immobilized in calcium alginate and chitosan-covered calcium alginate beads and studied in the fermentation of glucose and sucrose for ethanol production. The batch fermentations were carried out in an orbital shaker and assessed by monitoring the concentration of substrate and product with HPLC. Cell immobilization in calcium alginate beads and chitosan-covered calcium alginate beads allowed reuse of the beads in eight sequential fermentation cycles of 10 h each. The final concentration of ethanol using free cells was 40 g L-1 and the yields using glucose and sucrose as carbon sources were 78% and 74.3%, respectively. For immobilized cells in calcium alginate beads, the final ethanol concentration from glucose was 32.9 ± 1.7 g L-1 with a 64.5 ± 3.4% yield, while the final ethanol concentration from sucrose was 33.5 ± 4.6 g L-1 with a 64.5 ± 8.6% yield. For immobilized cells in chitosan-covered calcium alginate beads, the ethanol concentration from glucose was 30.7 ± 1.4 g L-1 with a 61.1 ± 2.8% yield, while the final ethanol concentration from sucrose was 31.8 ± 6.9 g L-1 with a 62.1 ± 12.8% yield. The immobilized cells allowed eight 10 h sequential reuse cycles to be carried out with stable final ethanol concentrations. In addition, there was no need to use antibiotics and no contamination was observed. After the eighth cycle, there was a significant rupture of the beads making them inappropriate for reuse.33

Crystal Structure Of 7-[(2e)-2-benzyl-idene-3-oxobut-oxy]-4-methyl-2h-chromen-2-one.

Two independent mol-ecules (A and B) comprise the asymmetric unit of the title compound, C21H18O4. There are significant conformational differences between the mol-ecules relating in particular to the relative orientation of the 3-oxo-2-(phenyl-methyl-idene)but-oxy substituent with respect to the superimposable chromen-2-one residues. To a first approximation, the substituents are mirror images; both are approximately perpendicular to the chromen-2-one fused ring system with dihedral angles of 88.50 (7) (A) and 81.96 (7)° (B). Another difference between the independent mol-ecules is noted in the dihedral angles between the adjacent phenyl and but-3-en-2-one groups of 8.72 (12) (A) and 27.70 (10)° (B). The conformation about the ethene bond in both mol-ecules is E. The crystal packing features C-H⋯O, C-H⋯π(ar-yl) and π-π [Cg⋯Cg = 3.6657 (8) and 3.7778 (8) Å] stacking inter-actions, which generate a three-dimensional network.71o222-22

Recent Advances in the Biocatalytic Asymmetric Reduction of Acetophenones and α.β-Unsaturated Carbonyl Compounds

Whole cells of living organisms, mainly of yeasts, have been used as reliable biocatalysts by synthetic organic chemists to perform redox reactions of various functional groups. This review focuses on the potential of these whole cells to reduce acetophenones and α.β-unsaturated carbonyl compounds (aldehydes and ketones) furnishing relevant chiral building blocks for fine chemicals and the pharmaceutical industries

Ethyl (E)-2-methoxy­imino-2-(4-nitro­benzo­yl)acetate

The title mol­ecule, C12H12N2O6, features an E conformation about the oxime group. The methoxy­imino and ester residues are effectively coplanar with each other (r.m.s. deviation for the nine non-H atoms = 0.127 Å) and almost orthogonal [with dihedral angles of 99.44 (13) and −77.85 (13)°, respectively] to the carbonyl and nitro­phenyl groups which lie to either side of this central plane. The crystal structure is consolidated by C—H⋯O contacts

(Z)-Ethyl 2-hydroxy­imino-2-(4-nitro­benz­yl)ethanoate

The title mol­ecule, C11H10N2O6, has a Z conformation about the C=N bond of the oxime unit. There are significant twists from planarity throughout the mol­ecule, the most significant being between the hydroxy­imino and ester groups which are effectively orthogonal with an N—C—C—Ocarbon­yl torsion angle of 91.4 (2)°. The crystal packing features oxime–benzoyl O—H⋯O contacts that lead to chains along [010] and C—H⋯O interactions also occur

Lanthanide nitrates as Lewis acids in the one-pot synthesis of 1,2,4-oxadiazole derivatives

In this work we report the use of lanthanide nitrates [Ln(NO3)3] acting as catalyst in direct one-pot synthesis of 3-benzoyl- and 3-acetyl-1,2,4-oxadiazoles derivatives from ketones, nitriles and nitric acid. This is the first example of one-pot synthesis of benzoyl- and acetyl 1,2,4-oxadiazoles derivatives preparation using acetophenones derivates with electron-donator groups.Neste trabalho relatamos o uso de nitratos de lantanídeos [Ln(NO3)3] atuando como catalisador na síntese de uma única etapa de derivados de 3-benzoíla- e 3-acetila-1,2,4-oxadiazóis a partir de cetonas, nitrilas e ácido nítrico. Este é o primeiro exemplo da síntese em única etapa de preparação de derivados benzoíla e acetila-1,2,4-oxadiazóis, usando acetofenonas com grupos doadores de elétrons.14371440Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq