Ammonia-mediated, large-scale synthesis of ammonia borane.

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.

Synthetic α-(aminomethyl)-γ-butyrolactones and their anti-pancreatic cancer activities.

Aminated α-methylene-γ-butyrolactones, which are readily synthesized with facile control of the diastereoisomerism, provide an economical and commercially-viable alternative to the use of aminated natural products. These aminoloactones, which exhibit excellent activity against three pancreatic cancer cell lines when measured at 10 µM-Panc-1, MIA PaCa-2, and BxPC-3-and are comparable to or better than parthenolide and dimethylaminoparthenolide (DMAPT, LC-1). It has also been shown that there is an effect on the biological activity depending on the identity of the amine.

One-pot synthesis of ammonia-borane and trialkylamine-boranes from trimethyl borate.

A one-pot procedure for the preparation of ammonia borane from trimethyl borate in 90% yield and >99% purity has been reported. This methodology has been modified to prepare a series of trialkylamine-boranes in 70-82% yields from trimethyl borate and lithium hydride/aluminum chloride in the presence of the corresponding trialkylamine.

One-pot asymmetric synthesis of 2- and 2,3-disubstituted tetrahydrofuran derivatives.

A novel and convenient one-pot asymmetric synthesis of 2- and 2,3-disubstituted tetrahydrofurans has been achieved in 56-81% yields and 86-99% ee from aliphatic and aromatic aldehydes via an allyl/crotyl/alkoxyallylboration-hydroboration-iodination-cyclization reaction sequence.

Bis-exo-2-norbornylboron triflate for stereospecific enolization of 3,3,3-trifluoropropionates.

The first boron-mediated enolization-aldolization of 3,3,3-trifluoropropionates has been reported. The preparation and application of bis-exo-bicyclo[2.2.1]heptan-2-ylboron triflate as a superior reagent for diastereospecific enolization has also been described.

Effects of gabapentin on cocaine self-administration, cocaine-triggered relapse and cocaine-enhanced nucleus accumbens dopamine in rats.

Gabapentin is a gamma-aminobutyric acid (GABA) analogue, with GABAmimetic pharmacological properties. Gabapentin is used for the treatment of seizures, anxiety and neuropathic pain. It has been proposed that gabapentin may be useful in the treatment of cocaine dependence. However, clinical trials with gabapentin have shown conflicting results, while preclinical studies are sparse. In the present study, we investigated the effects of gabapentin on intravenous cocaine self-administration and cocaine-triggered reinstatement of drug-seeking behavior, as well as on cocaine-enhanced dopamine (DA) in the nucleus accumbens (NAc). We found that gabapentin (25-200 mg/kg, i.p., 30 min or 2 h prior to cocaine) failed to inhibit intravenous cocaine (0.5 mg/kg/infusion) self-administration under a fixed-ratio reinforcement schedule or cocaine-triggered reinstatement of cocaine-seeking behavior. In vivo microdialysis showed that the same doses of gabapentin produced a modest increase (approximately 50%, p<0.05) in extracellular NAc GABA levels, but failed to alter either basal or cocaine-enhanced NAc DA. These data suggest that gabapentin is a weak GABA-mimic drug. At the doses tested, it has no effect in the addiction-related animal behavioral models here tested. This is in striking contrast to positive findings in the same animal models shown by another GABAmimetic--gamma-vinyl GABA (see companion piece to present article).

Preparation of ammonia borane in high yield and purity, methanolysis, and regeneration.

Ammonia borane (AB) is emerging as a promising solid hydrogen carrier, particularly for power generation in portable devices that employ proton-exchange membrane fuel cells. A preparative-scale synthesis of AB from sodium borohydride and ammonium salts in high yields (> or =95%) and very high purity (> or =98%) has been described. The first systematic study of a transitional metal-catalyzed alcoholysis of AB, comparison of the methanolysis to the hydrolysis of AB, and regeneration of AB from ammonium tetramethoxyborate also has been described.