Search results for "Acetone"
showing 10 items of 350 documents
Enzymes for the NADPH-dependent reduction of dihydroxyacetone and D-glyceraldehyde and L-glyceraldehyde in the mould Hypocrea jecorina
2006
The mould Hypocrea jecorina (Trichoderma reesei) has two genes coding for enzymes with high similarity to the NADP-dependent glycerol dehydrogenase. These genes, called gld1 and gld2, were cloned and expressed in a heterologous host. The encoded proteins were purified and their kinetic properties characterized. GLD1 catalyses the conversion of d-glyceraldehyde and l-glyceraldehyde to glycerol, whereas GLD2 catalyses the conversion of dihydroxyacetone to glycerol. Both enzymes are specific for NADPH as a cofactor. The properties of GLD2 are similar to those of the previously described NADP-dependent glycerol-2- dehydrogenases (EC 1.1.1.156) purified from different mould species. It is a reve…
The tris(hexasulphido)platinate(IV) ion: Seven-membered chelate rings
1988
Le sel complexe [[(C 6 H 5 ) 4 P] 2 Pt(S 6 ) 3 ] a l'etat cristallin est prepare a partir de [N(C 2 H 5 ) 4 ] 2 PtS 17 ou (NH 4 ) 2 PtS 17 •H 2 O en solution dans l'acetone. Caracterisation structurale et configuration geometrique de l'anion Pt(S 6 ) 3 2−
Five coordinate complexes of the type Rh(SnCl3)(NBD)L2
1983
Several new rhodium complexes of general formulation Rh(SnCl3)(NBD)L2 (L=P(OMe)3, P(OMe)2Ph, P(OMe)Ph2, P(OEt)3, P(OEt)2Ph, P(OEt)Ph2, P(O-i-Pr)3, P(OPh)3) have been prepared and characterized by elemental analysis and by i.r. and n.m.r. spectroscopy. The complexes show low or no conductivity in acetone solution and react with carbon monoxide (1 atm).
A Combined Theoretical and Experimental Approach for Platinum Catalyzed 1,2-Propanediol Aqueous Phase Reforming
2017
Decomposition pathways of 1,2-propanediol (1,2-PDO) on platinum were investigated by means of experiments and quantum-mechanical calculations. Different reaction paths on a Pt(111) model surface were computationally screened. Gas and liquid phase products distribution for aqueous phase reforming of 1,2-PDO solutions was experimentally analyzed. A mechanistic approach was used to trace the preferred paths according to calculated activation barriers of the elementary steps; in this way, the presence or absence of some hypothesized intermediates in the experiments was computationally rationalized. Hydroxyacetone was demonstrated to be among the most favored decomposition products. The competit…
Extremely potent antifeedant neo-clerodane derivatives of scutecyprol A
2004
Two known neo-clerodane diterpenoids, scutecyprol A (1) and scutalbin C (2), have been isolated from the acetone extract of the aerial parts of Scutellaria sieberi. The antifeedant activity of scutecyprol A (1), of its 15-oxo derivative (3), and of several halohydrins (4-9), synthesized starting from compounds 1 and 3, against Spodoptera littoralis have been determined and structure-antifeedant relationships are discussed.
Density, Speed of Sound, and Refractive Index of 1-Ethyl-3-methylimidazolium Trifluoromethanesulfonate with Acetone, Methyl Acetate, and Ethyl Acetat…
2009
Densities, speeds of sound, and refractive indices of the binary mixtures of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([emim][triflate]) with acetone, methyl acetate, and ethyl acetate were experimentally measured over the whole range of compositions at T = (278.15 to 328.15) K and a pressure of 0.1 MPa. From these experimental data, excess molar volumes, excess isentropic compressibilities, molar refractions, and deviations in refractive indices have been calculated and fitted to an extended version of the Redlich−Kister equation, which takes into account the dependence on composition and temperature simultaneously. The Prigogine−Flory−Patterson theory has been used to specula…
Activity against microorganisms affecting cellulosic objects of volatile constituents of Leonotis nepetaefolia from Nicaragua
2014
The chemical composition of the essential oil from aerial parts of L. nepetaefolia (L.) R. Br. collected in Nicaragua was evaluated by GC and GC-MS. The main components were (Z)-phytol (22.8%), caryophyllene oxide (18.9%) and hexahydrofarnesylacetone (9.0%). The antibacterial activity against several Gram + and Gram-bacteria, including Bacillus cereus and B. subtilis, both infesting historical cellulosic material, was also determined. B. cereus, B. subtilis and Staphylococcus epidermis were the most affected by the action of the oil.
Studies on adducts of organotin(IV) halides with bis(acetylacetone)ethylenediimine
1971
The solid state configuration of 1/1 adducts, formed by mono-, di- and tri-organotin(IV) halides with the potentially tetradentate ligand bis(acetylacetone)ethylenediimine, has been investigated. The infrared spectra suggest that the neutral ligand coordinates SnIV through N (or O) atoms of the H-bonded acetylacetoneimine moieties. The skeletal vibrations associated to Sn-C and Sn-Cl bonds are consistent with square planar configurations of the organotin(IV) halide moieties, where SnCl3 and C3Sn groups would be T-shaped, and Alk2SnCl2 would have trans-dialkyl, trans-dichloro arrangements. The latter configuration is supported by the magnitude of the quadrupole splittings. Measurements of th…
6-Prenyloxy-7-methoxycoumarin, a coumarin-hemiterpene ether from Carduus tenuiflorus
1992
Abstract From the acetone extract of Carduus tenuiflorus , a new coumarin-hemiterpene ether was isolated, which was identified as 6-(3,3-dimethylallyloxy)-7-methoxycoumarin. The synthesis of this coumarin and that of its positional isomer 7-(3,3-dimethylallyloxy)-6-methoxycoumarin were carried out from esculetin. Two other coumarins, three lignans and three flavonoids were also isolated.
Use of Saccharomyces cerevisiae as a whole cell system for aldol condensation in organic medium: Study of the factors affecting the biotransformation
2011
Abstract Saccharomyces cerevisiae has been employed as a whole cell catalyst for a number of asymmetric transformations. This work explores the ability of this microorganism to carry out the asymmetric aldol condensation between 4-nitrobenzaldehyde and acetone. For this purpose, lyophilized cells of the FY86 laboratory strain from stationary phase cultures were employed. This reaction shows stereoselectivity, and its progress is affected by the water concentration in the medium, temperature and the growth stage of the yeast culture. Cell lysis experiments indicate that activity responsible for this biotransformation is located in the soluble fraction.