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Journals and Conferences
Ammonia promotes the synthesis of pure ammonia borane (AB) in excellent yields from sodium borohydride and ammonium sulfate in tetrahydrofuran under ambient conditions. An examination of the influence of added ammonia reveals that it is incorporated into the product AB, contrary to its perceived function as a catalyst or a co-solvent. Mechanistic studies… (More)
This study compares the physicochemical properties of cefixime (CFX) solid dispersions prepared by freeze drying method. Solid dispersions of cefixime in polyvinylpyrrolidone (PVP) K30 were prepared and characterized by intrinsic dissolution, powder X-ray diffraction, Fourier transform infrared spectroscopy and Scanning electron microscopy. CFX:PVP K30… (More)
Complexation of amines with borane converts them to hypergols or decreases their ignition delays (IDs) multifold (with white fuming nitric acid as the oxidant). With consistently low IDs, amine-boranes represent a class of compounds that can be promising alternatives to toxic hydrazine and its derivatives as propellants. A structure-hypergolicity… (More)
A simple, large-scale synthesis of ammonia borane from NaBH4 and (NH4)2SO4 at 0 °C-rt in THF containing 5% NH3 is described. The presence of ammonia is critical for the reaction to proceed and allows the reaction at high concentrations and ambient temperature without the need for anhydrous solvent or inert atmosphere.
The first general open-flask synthesis of amine-boranes with inexpensive and readily available reagents, such as sodium borohydride, sodium bicarbonate, water, and the desired amines is described. Even amines bearing borane-reactive functionalities, such as alkene, alkyne, hydroxyl, thiol, ester, amide, nitrile, and nitro are well tolerated. Some of these… (More)
Background Resveratrol, a plant-derived polyphenol, has been reported to improve glucose metabolism and vascular function and to extend life span in animal models, but studies in humans have been inconclusive. Methods In a randomized, double-blind crossover study, we treated older glucose-intolerant adults (n = 30) with resveratrol (2-3 g/daily) or… (More)
An amine-ammonium salt equilibration-metathesis sequence provides high-purity amine-boranes in excellent yields from sodium borohydride in refluxing reagent-grade tetrahydrofuran in an open flask.
Under open-flask conditions, ammonia borane hydroborates olefins in refluxing tetrahydrofuran. Unlike conventional hydroboration, the Lewis base (ammonia) is not dissociated from the boron center. Terminal alkenes selectively provide ammonia-trialkylborane complexes. On the other hand, internal alkenes afford aminodialkylboranes via a metal-free… (More)