Metabolism of levamisole and kinetics of levamisole and aminorex in urine by means of LC-QTOF-HRMS and LC-QqQ-MS

The antihelminthic drug Levamisole can enhance cocaine effects by conversion into the amphetamine-like drug aminorex. We describe an LC-MS method for the determination of levamisole and its metabolite aminorex in human urine. Selectivity is given, calibration curves were linear within the calibration range 2.5–250 ng/mL; limits of the method were LoD 0.51 ng/mL, LoQ 1.02 ng/mL for levamisole and LoD 0.65 ng/mL, LoQ 0.76 ng/mL for aminorex. Precision data was in accordance with the guidelines (intraday precision for aminorex ranged between 5.75 and 11.0 % for levamisole between 8.36 and 10.9 %; interday precision for levamisole 10.9–16.9 % and for aminorex 7.64–12.7 %; accuracy data for levamisole ?1.96 to –14.3 % and for aminorex?11.9 to–18.5 %). The validated method was successfully applied to study the urinary excretion of levamisole after the administration of 100 mg of levamisole orally. Levamisole and aminorex could be detected in post-administration urine samples. Levamisole could be detected up to 39 h after ingestion, while aminorex was detectable up to 54 h. Maximum aminorex concentrations were 45 ng/mL urine. Further metabolites of levamisole after oral ingestion by means of liquid chromatography hybrid quadrupole time-of-flight high-resolution mass spectrometry (LC-QTOF-HRMS) were identified. Only 0.5 % of the ingested drug was quantified as unchanged levamisole in urine. Besides aminorex, five isomers of aminorex and 4 hydroxy-metabolites of aminorex or its isomers were found. Furthermore, levamisole is also hydroxylated and eliminated free or conjugated with sulfate or glucuronide into urine.     

Low-Valent Titanium Mediated Deprotection of N-Allyl/Benzyl Amines: A New Approach

A novel low-valent titanium (LVT) mediated cleavage of N-allyl/benzyl amines is reported. Regio- and chemo-selective cleavages were also observed.     

A New Method of Cyclodehydration of 3,3-Dialkyl-1-Oxo-1-(2- hydroxyaryl)propan-3-ols to 2,2-Dialkyl-4-chromanones: Synthesis of Cannabinoid Synthon

A new method for cyclodehydration of o-hydroxyaryl-β-ketols to 4-chromanones using HMPT is described. The method has general applicability. It is particularly useful for the cyclisation of labile intermediates as exemplified by the synthesis of cannabinoid synthon, 2-methyl-2-(4-methyl-3-pentenyl)-7-methoxy-4-chromanone.     

Synthesis of Cycloartocarpesin Trimethyl Ether

The synthesis of chromenoflavone, cycloartocarpesin trimethyl ether (1b) has been achieved through the aroylation of lithium enolate of evodionol (2) with 2,4-dimethoxybenzoyl chloride followed by cyclodehydration of the β-diketone (3) with D-toluenesulphonic acid.     

Interfacial synthesis of bisphenol A tetrachlorocyclotriphosphazene from bisphenol A and hexachlorocyclotriphosphazene

The effect of solvent purity on the synthesis and yield of bisphenol A tetrachlorocyclotriphosphazene (BATCCP) has not been described in the literature. The purpose of this research was to synthesize BATCCP hybrid monomers and to evaluate the effect of solvent purity on the BATCCP production. BATCCP monomers were prepared by an interfacial procedure in a water/toluene system as a function of time with the assistance of a phase transfer catalyst, tetraoctylammonium bromide. ¹H and ³¹P NMR confirmed the production of BATCCP monomer by the appearance of chemical shifts at 7.18 and 5.35 ppm in the ¹H NMR and 23.4 and 13.9 ppm in the ³¹P NMR, respectively. Distillation of the toluene, not suggested in previous reports of HCCP hybrid synthesis, resulted in an improvement of actual % yield to 40% and stability of the product throughout the 1440 min reaction as confirmed by MALDI, compared with an 11% actual yield at 15 min, decaying to 2% over a 1440 min reaction when the synthesis was performed with ‘anhydrous toluene’ as provided commercially without further distillation.     

Application of magnetic nanoparticles for the extraction of radium-226 from water samples

Bare (unmodified) and crown ether (CE)-modified Fe₃O₄ magnetic nanoparticles (MNPs) were investigated for the rapid extraction of ²²⁶Ra from water samples. It involved synthesizing the MNPs, introducing them into the sample solutions, ultrasonicating and agitating the suspension, magnetically separating the nanoparticles from solution, and measuring the ²²⁶Ra content in the supernatant. Experimental parameters such as salt choice, salt concentration and pH were optimized to achieve maximum extraction of ²²⁶Ra onto the MNPs. ²²⁶Ra content was determined using a Hidex 300SL liquid scintillation counter with α/β separation capability, or a gamma spectrometric detection system. The bare Fe₃O₄ nanoparticles showed significant pH dependence for the extraction of ²²⁶Ra from an aqueous solution over a pH range of 2–10. They gave an extraction of 95 ± 1 and 98 ± 1 % at pH 9 in 0.1 M NaCl and 0.1 M NaClO₄, respectively, whereas an extraction of 8–24 % was obtained, over the pH ranges from 2 to 5. The CE-modified MNPs yielded extraction efficiencies as high as 99 ± 1 % in the presence of 0.01 M picric acid at pH 4. This study demonstrates that the surface functionalization of Fe₃O₄ MNPs with suitable ligand modification can offer a selective mode of extraction for ²²⁶Ra in the presence of its daughter progenies.