Presence of Flazin in Miso and Identification of Four Tryptophan-Derived ß-Carbolines Formed during Fermentation.

In miso, due to the substantial presence of genistein, flazin is often overlapped and masked by genistein in HPLC analysis. Flazin in the miso extracts could be resolved with genistein through medium-pressure liquid chromatography run under a nonacidified methanol-water system and subsequently fractionated by semipreparative HPLC and identified by NMR spectroscopic analysis. As referenced, flazin was detected in all 11 locally marketed miso products, with contents ranging from 3.

Stereoselective synthesis of 2,3,4-highly substituted oxetanes by intramolecular C-C bond forming Michael addition.

Stereoselective synthesis of 2,3,3,4-tetrasubstituted oxetanes via intramolecular allyl or benzyl anion four-membered ring cyclization of vinylogous urethane derivatives is presented. The resulting products featuring a β-pyrrolidinyl ester at C3 were readily transformed into the corresponding 3-α,β-unsaturated ester substituted oxetanes by Cope elimination reactions.

Identification of di-isononyl phthalate metabolites for exposure marker discovery using in vitro/in vivo metabolism and signal mining strategy with LC-MS data.

Di-isononyl phthalate esters (DINPs) are endocrine-disrupting chemicals and have replaced di(2-ethylhexyl) phthalate (DEHP) as the major plasticizer for poly(vinyl chloride) (PVC) products in recent years. Exposure marker discovery of DINPs is crucial, because of their high potential for human exposure and toxicity. Here, we propose an alternative approach for tracing signals derived from stable isotope-labeled precursors with varied labeling ratios to efficiently filter probable metabolite signals.

Asymmetric [3,3]- and [1,3]-sigmatropic rearrangements of gamma-allyloxy vinylogous urethanes.

Vinylogous urethanes derived from condensation of prolinol or prolinol tert-butyldimethylsilyl ether with 4-allyloxyketoester were found to undergo a thermal [3,3]-sigmatropic rearrangement, providing compounds with N-substituted quaternary carbon centers. Cyclizations (subsequently or in situ) of the rearranged products generated hexahydro-3,4-dioxa-8a-aza-as-indacen-2-ones. Various terminally substituted allyloxy ketoesters and arylmethoxy ketoesters were found to generate tricyclic compounds via [1,3]-sigmatropic rearrangement.

Glass distilling collector applied for HCN recovery from submerged culture broth and fruiting body of Pleurotus eryngii for identification and quantification.

Detection and surveillance of food commodities containing cyanide is a crucial issue of food safety. In this study, five strains of Pleurotus eryngii (P. eryngii) were grown in submerged culture of yeast malt broth (YMB) with the suspected production of HCN.

An electrospray ionization tandem mass spectrometry based system with an online dual-loop cleanup device for simultaneous quantitation of urinary benzene exposure biomarkers trans,trans-muconic acid and S-phenylmercapturic acid.

An electrospray ionization tandem mass spectrometry (ESI-MS/MS) system with an online dual-loop cleanup device was developed for simultaneous quantitation of the urinary benzene exposure biomarkers trans,trans-muconic acid (ttMA) and S-phenylmercapturic acid (SPMA). The cleanup device was constructed from an autosampler, two electrically operated two-position switching valves, a reversed-phase C18 trap cartridge, a 200-microL loop, and two solvent-delivery pumps. The device was interfaced directly with a triple-quadrupole mass spectrometer and fully controlled by computer software and hardware.