10.1039/d0ra03420g
The research focuses on the efficient production of bio-based aromatics, specifically vanillin, through the aerobic oxidation of native soft wood lignin. The experiments utilized an aqueous solution of tetrabutylammonium hydroxide (Bu4NOH) to oxidize Japanese cedar wood flour at 120°C for 4 hours under oxygen, yielding vanillin at 23.2 wt% based on the Klason lignin content. This yield is comparable to the alkaline nitrobenzene oxidation method, a benchmark for lignin oxidation processes. The study suggests that vanillin formation primarily occurs through successive reactions: alkaline-catalyzed degradation of lignin's β-ether linkages to form a glycerol end group, oxidation of this end group by O2 to an aldehyde group, and subsequent release of vanillin. The research also indicates that Bu4NOH's performance in vanillin production is superior to simple alkalis like NaOH, due to Bu4NOH being a stronger base and the cation Bu4N+ suppressing the disproportionation of vanillin precursors. The analyses involved high-performance liquid chromatography (HPLC) and gas chromatography/mass spectrometry (GC/MS) to quantify the yields of vanillin, vanillic acid, and other products.
10.1002/jlcr.465
The research aimed to synthesize radiolabeled phosphodiesterase-4 (PDE4) inhibitors, specifically Ro 20-1724, R-, R/S-, and S-rolipram, using carbon-11 (C-11) for positron emission tomography (PET) imaging. The purpose was to develop radioligands that could selectively bind to the high-affinity conformational binding state of PDE4, an enzyme that plays a crucial role in the cAMP-mediated signal transduction pathway and is implicated in neuropsychiatric disorders and inflammatory diseases. The team achieved this by O-[methylation of the respective phenolic precursors with [C]methyl iodide, resulting in radiolabeled products with high radiochemical yields and purity. The chemicals used in the process included iodotrimethylsilane for selective dealkylation, tetrabutylammonium hydroxide (TBAOH) as a base, and various solvents such as tetrahydrofuran (THF), dimethylformamide (DMF), and methylene chloride for the extraction and purification steps. The final radiolabeled products were prepared with high radiochemical purity (>99%), yields (45-75%, decay-corrected), and specific activities (18.5-92.5 GBq/μmol) within 30 minutes from end-of-bombardment, demonstrating their potential for PET imaging studies of PDE4 in vivo.
10.1016/S0040-4020(01)87129-5
The study investigates the SRN1 reaction between 2-chloromethyl-3-nitroimidazo[1,2-a]pyridine and various nitronate anions, including those from aliphatic, cyclic, and heterocyclic nitroalkanes, to synthesize new potential pharmacological derivatives. The reaction involves the C-alkylation of 2-chloromethyl-3-nitroimidazo[1,2-a]pyridine by nitronate anions, followed by base-promoted nitrous acid elimination to form products with a trisubstituted double bond at the 2-position. Key chemicals include 2-chloromethyl-3-nitroimidazo[1,2-a]pyridine as the starting material, various nitroalkanes (e.g., 2-nitropropane, nitrocyclopentane) as sources of nitronate anions, and tetrabutylammonium hydroxide as a phase-transfer catalyst. The synthesized compounds are being evaluated for their potential pharmacological properties, particularly their affinity for specific receptors related to anxiolytic and hypnotic effects.
T, 
F, 
C
