Search results for "tetrahydrofuran"

CCDC 149238: Experimental Crystal Structure Determination

2001

Related Article: S.Mahboobi, I.Dechant, H.Reindl, H.Pongratz, A.Popp, D.Schollmeyer|2000|J.Heterocycl.Chem.|37|307|doi:10.1002/jhet.5570370215

CCDC 685282: Experimental Crystal Structure Determination

2009

Related Article: A.Jahel, N.V.Vologdin, N.Pirio, H.Cattey, P.Richard, P.Meunier, J.-C.Hierso|2008|Dalton Trans.||4206|doi:10.1039/b809244n

CCDC 1834563: Experimental Crystal Structure Determination

2018

Related Article: Serhii Krykun, Vincent Croué, Magali Allain, Zoia Voitenko, Juan Aragó, Enrique Ortí, Sébastien Goeb, Marc Sallé|2018|J.Mater.Chem.C|6|13190|doi:10.1039/C8TC04730H

Inhibitory effects on mitochondrial complex I of semisynthetic mono-Tetrahydrofuran acetogenin derivatives

2003

Modifications in the terminal alpha,beta-unsaturated gamma-methyl-gamma-lactone moiety or in the alkyl chain that links this terminal gamma-lactone with the alpha,alpha'-dihydroxylated THF system of the natural mono-tetrahydrofuranic acetogenins, annonacin and annonacinone, led to the preparation of eight semisynthetic derivatives. Their inhibitory effects on mitochondrial complex I is discussed and compared with that of the classical complex I inhibitor, rotenone.

Diversity in Itraconazole Cocrystals with Aliphatic Dicarboxylic Acids of Varying Chain Length

2013

The cocrystal formation potential of itraconazole, a potent antifungal drug, with C2–C10 aliphatic dicarboxylic acids has been investigated. Using two experimental screening techniques (solvent-assisted grinding and evaporation-based crystallization), the cocrystals of itraconazole with C2–C7 dicarboxylic acids have been successfully synthesized and characterized by powder X-ray diffraction, solid state nuclear magnetic resonance, Raman spectroscopy, and thermal analysis. The characterized multicomponent compounds include anhydrous cocrystals (malonic, succinic, glutaric, and pimelic acids), a cocrystal hydrate (adipic acid), and cocrystal solvates with acetone and tetrahydrofuran (oxalic a…

Determination of butyl methoxydibenzoylmethane, benzophenone-3, octyl dimethyl PABA and octyl methoxycinnamate in lipsticks.

2003

The complex composition of lipstick formulations usually needs the use of organic solvents for sample dissolution. A treatment based on dissolution of cosmetic samples in ethanol-water (70 : 30, v/v) by use of ultrasonic irradiation is proposed. A C(18) stationary phase and an isocratic mobile phase of ethanol:water:acetic acid (70 : 29.5 : 0.5, v/v/v) with a flow rate of 1 mL min(-1) and an injection volume of 20 microL is proposed for the high-pressure liquid chromatography (HPLC) determination of four UV-filters, and detection was carried out at 309 nm. The limit of the chromatographic detection was 7.0 microg mL(-1) for butyl methoxydibenzoylmethane, 1.5 microg mL(-1) for benzophenone-3…

Rearrangement of the carbon skeleton in the intramolecular photoadduct of anthracene and benzene rings

2003

Abstract The effectivity of optical switching between anthracene derivatives 3a,b and their intramolecular photocycloadducts 4a,b is impaired by traces of acid. The systematic treatment of 4a,b with an increasing excess of formic acid revealed that—apart from the normal enolether cleavage 4a,b → 6a,b → 7a,b —a cleavage with rearrangement of the carbon skeleton can occur: 5b → 6b′ . The driving force is a stability enhancement of the involved carbenium ions 5b → 5b′ . A further increased excess of formic acid leads finally to a competitive ether cleavage in the tetrahydrofuran ring 5b → 8 .

Organic solvent desorption from two tegafur polymorphs.

2013

Desorption behavior of 8 different solvents from α and β tegafur (5-fluoro-1-(tetrahydro-2-furyl)uracil) has been studied in this work. Solvent desorption from samples stored at 95% and 50% relative solvent vapor pressure was studied in isothermal conditions at 30 °C. The results of this study demonstrated that: solvent desorption rate did not differ significantly for both phases; solvent desorption in all cases occurred faster from samples with the largest particle size; and solvent desorption in most cases occurred in two steps. Structure differences and their surface properties were not of great importance on the solvent desorption rates because the main factor affecting desorption rate …

1981

The anionic polymerization of tert-butyl methacrylate (TBMA) in tetrahydrofuran, using Na+ and Cs+ as counterions proceeds without side reactions even at room temperature. The resulting molecular weight distributions are nearly monodisperse (Mw/Mn ⩽ 1,01). The rate constants for the propagation of ion pairs were measured in the range from + 15 to −100°C. The Arrhenius plots are linear, but different for the two counterions, resulting in the following numerical values for the frequency exponent A and the activation energy Ea: A = 8,5 and Ea = 7,2 kcal/mol = 30 kJ/mol for Na+; A = 9,5 and Ea = 5,6 kcal/mol = 23 kJ/mol for Cs+. The difference between the counterions, which is in contrast to th…

Synthesis of AB and ABA block copolymers as compatibilizers in nylon 6/polycarbonate blends

1996

Nylon 6 (Ny6) and Bisphenol A polycarbonate (PC) are immiscible and form biphasic blends. To improve the compatibility of Ny6 and PC several ABA and AB Ny6/PC block copolymers were synthesized, and their compatibilizing behavior on the blends were tested. Block copolymers were prepared by reacting monoamino- or diamino-terminated Ny6 homopolymers with high molecular weight PC at 130°C in anhydrous DMSO. The reaction of diamino- and monoamino-terminated Ny6 with polycarbonate produces block copolymers of the type PC-Ny6-PC (ABA) and PC-Ny6 (AB), respectively, plus a certain amount of unconverted PC degradated to lower molecular weights. To separate the block copolymer from the unconverted PC…