Copper-mediated trifluoromethylation of potassium alkynyltrifluoroborates with Langlois' reagent

Synthesis of trifluoromethylated acetylenes by copper-mediated trifluoromethylation of potassium alkynyltrifluoroborates with CF₃ radicals generated from NaSO₂CF₃ and tert-butyl hydroperoxide (TBHP) is communicated. The trifluoromethylated acetylenes were obtained in good to moderate yields. The presented method tolerates a wide range of aromatic, heteroaromatic, and aliphatic potassium alkynyltrifluoroborates.     

The multi-cavity free-electron laser

Analysis is made of a free-electron laser with many optical cavities where the cavities communicate with each other, not optically, but through the electron beam. Analytic analysis is made in a one-dimensional, linear approximation. A general expression is given for the growth rate in the exponential (high current) regime. In the regime where lethargy is important expressions are given in the two opposite limits of small and large numbers of cavities and bunches. Numerical simulation results, still in the one-dimensional approximation, but including nonlinearities, are presented. Three examples of the multi-cavity free-electron laser (MC/FEL) are presented.     

Characterisation of a series of acetals/ketals of bis(2-nitrophenyl) ethanediol and bis(4,5-dimethoxy-2-nitrophenyl) ethanediol under APCI mass spectrometric conditions

A series acetals/ketals of aldehydes and ketones formed by the reaction of two photolabile protecting groups, bis(2-nitrophenyl) ethanediol and bis(4,5-dimethoxy-2-nitrophenyl) ethanediol (I and II, respectively), were analysed under EI, LSIMS, ESI and APCI conditions to obtain molecular weights as well as structural information. The EI and LSIMS techniques failed to give molecular weight information. The positive ESI yielded [M + H](+) ions only for I; however, with added Na(+) both I and II formed [M + Na](+) adducts. But upon decomposition, the [M + Na](+) ions yielded Na(+) ion as the only product ion. Similarly, under negative ion ESI conditions both I and II gave molecular weight information by forming adduct ions with halide anions (F(-), Cl(-), Br(-) and I(-)); however, they did not give structural information as they resulted in only the halide anion as the abundant fragment ion upon dissociation. All the compounds formed abundant M(-*) ions under negative ion APCI conditions, and their MS/MS spectra showed characteristic fragment ions; hence the acetals/ketals of I and II could be successfully characterized under negative ion APCI conditions.     

Design,synthesis, anticancer activity,and in silico studies of novel imidazo[1,2-a]pyridine based 1H-1,2,3-triazole derivatives

A novel series of imidazo[1,2-a]pyridine based 1H-1,2,3-triazole derivatives were designed, synthesized, and evaluated for their anticancer activity against two different human cancer cell lines. Most of the synthesized compounds displayed anticancer activity with IC₅₀ values from 2.35 to 120.46 μM. Furthermore, compounds 9b , 9c, 9d, 9f , and 9j showed potent inhibitory activity against cancer cell lines, with IC₅₀ values close to that of standard drug. It is important to note that compound 9d was more potent than the standard drug cisplatin with IC₅₀ values of 10.89 and 2.35 μM against Hela cell line and MCF-7 cell line, respectively.     

A multi-server queueing model with server consultations

We consider a multi-server queueing model in which the arrivals occur according to a Markovian arrival process. One of the servers, henceforth referred to as the main server, offers consultation to fellow servers (referred to as regular servers) apart from serving the customers. A regular server may request a consultation only when serving a customer and is offered consultation on a first-come-first-served basis by the main server. The main server gives a preemptive priority to regular servers (for consulting) over customers. Thus, the main server can undergo interruptions during his/her servicing the customers. Under the assumptions of exponential services and consultations, the model is analyzed in steady-state using the well-known matrix-analytic methods. Illustrative numerical examples to bring out the qualitative nature of the model under study are presented.     

ChemInform Abstract: Towards Detection of a Long‐Lived Protonated Metal Cation: Generation of GeH2+ Using High‐Energy Collisions.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

A pharmacokinetic study to correlate the hypoglycemic effect of phlorizin in rats: Identification of metabolites as inhibitors of sodium/glucose cotransporters

Phlorizin (PRZ) is a natural product that belongs to a class of dihydrochalcones. The unique pharmacological property of PRZ is to block glucose absorption or reabsorption through specific and competitive inhibitors of the sodium/glucose cotransporters (SGLTs) in the intestine (SGLT1) and kidney (SGLT2). This results in glycosuria by inhibiting renal reabsorption of glucose and can be used as an adjuvant treatment for type 2 diabetes. The pharmacokinetic profile, metabolites of the PRZ, and efficacy of metabolites towards SGLTs are unknown. Therefore, the present study on the characterization of hitherto unknown in vivo metabolites of PRZ and pharmacokinetic profiling using liquid chromatography-electrospray ionization tandem mass spectrometry (LC/ESI/MS/MS) and accurate mass measurements is undertaken. Plasma, urine, and feces samples were collected after oral administration of PRZ to Sprague–Dawley rats to identify in vivo metabolites. Furthermore, in silico efficacy of the identified metabolites was evaluated by docking study. PRZ at an intraperitoneal dose of 400 mg/kg showed maximum concentration in the blood to 439.32 ± 8.84 ng/mL at 1 h, while phloretin showed 14.38 ± 0.33 ng/mL at 6 h. The pharmacokinetic profile of PRZ showed that the maximum concentration lies between 1 and 2 h after dosing. Decreased blood glucose levels and maximum excretion of glucose in the urine were observed when the PRZ and metabolites were observed in plasma. The identification and characterization of PRZ metabolites by LC/ESI/MS/MS further revealed that the phase I metabolites of PRZ are hydroxy (mono-, di-, and tri-) and reduction. Phase II metabolites are O-methylated, O-acetylated, O-sulfated, and glucuronide metabolites of PRZ. Further docking study revealed that the metabolites diglucuronide metabolite of mono-hydroxylated PRZ and mono-glucuronidation of PRZ could be considered novel inhibitors of SGLT1 and SGLT2, respectively, which show better binding affinities than their parent compound PRZ and the known inhibitors.