the synthesis of functionalized 2-oxo-2h-coumarin derivatives has been studied by a one-pot reaction of o-hydroxybenzaldehyde, ethyl 2-bromoacetate and triphenylphosphine in the presence of catalytic amount of triethyl amine in etoac, water or under solvent free conditions. we have found the best results obtained under solvent free condition.

The synthesis of functionalized 2-oxo-2H-coumarin derivatives has been studied by a one-pot reaction of o-hydroxybenzaldehyde, ethyl 2-bromoacetate and triphenylphosphine in the presence of catalytic amount of triethyl amine in EtOAc, water or under solvent free conditions. We have found the best results obtained under solvent free condition.

Irrigated agriculture is dependent on an adequate water supply of usable quality. Water used for irrigation can vary greatly in quality depending upon type and quality of dissolved salts. Salts are present in irrigation water in relatively small but significant amounts. The problems that result very both and kind, degree and modified by soil, climate and crop. The aim this paper is to monitor t...

F or young adults who frequent hookah bars, water pipe smoking leads to elevated levels of nicotine, cotinine, tobacco-related carcinogens, and volatile organic compounds (VOCs) in urine. These findings, published May 16 in Cancer Epidemiology, Biomarkers, and Prevention, raise alarms about a practice rapidly gaining in popularity. " We should forget the myth that hookah smoking is not harmful,...

We present a detailed analysis of the free energy surface of a well characterized rigid model for water in supercooled states. We propose a functional form for the liquid free energy, supported by recent theoretical predictions [Y. Rosenfeld and P. Tarazona, Mol. Phys. 95, 141 (1998)], and use it to locate the position of a liquid-liquid critical point at T(C')=130+/-5 K, P(C')=290+/-30 MPa, an...

Temperature-dependent free radical reactions were investigated using nitroxyl radicals as redox probes. Reactions of two types of nitroxyl radicals, TEMPOL (4-hydroxyl-2,2,6,6-tetramethylpiperidine-N-oxyl) and carbamoyl-PROXYL (3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-N-oxyl), were tested in this paper. Heating a solution containing a nitroxyl radical and a reduced form of glutathione (GSH) c...

We assessed respiratory and cutaneous water loss in trained tippler pigeons (Columba livia) both at rest and in free flight. In resting pigeons, exhaled air temperature T(ex) increased with ambient air temperature T(a) (T(ex)=16.3+0.705T(a)) between 15 degrees C and 30 degrees C, while tidal volume V(T) (V(T)=4.7+/-1.0 ml, mean +/- S.D. at standard temperature and pressure dry) and breathing fr...

To understand water-protein interactions in solution, the electrostatic field is calculated by solving the Poisson-Boltzmann equation, and the free energy surface of water is mapped by translating and rotating an explicit water molecule around the protein. The calculation is applied to T4 lysozyme with data available on the conservation of solvent binding sites in 18 crystallographically indepe...

The estimation of milk consumption in free-ranging seals using tritium dilution techniques makes the key assumption that the animals drink no pre-formed water during the experimental period. However, frequent observations of unweaned Antarctic fur seal pups drinking water at Iles Kerguelen necessitated the testing of this assumption. We estimated water flux rates of 30 pups (10.7+/-0.3 kg) in f...