Eugene P. Mazzola

Atranones: Novel diterpenoids from the toxigenic mold Stachybotrys atra

Abstract The toxigenic mold Stachybotrys atra produces a new class of elaborated diterpenoid dolabellanes, the C 24 atranones, which have several unusual structural features, including an enol-lactone ring system.

Analysis of Processing Contaminants in Edible Oils. Part 1. Liquid Chromatography–Tandem Mass Spectrometry Method for the Direct Detection of 3-Monochloropropanediol Monoesters and Glycidyl Esters

A new analytical method has been developed and validated for the detection of glycidyl esters (GEs) and 3-monochloropropanediol (3-MCPD) monoesters in edible oils. The target compounds represent two classes of potentially carcinogenic chemical contaminants formed during the processing of edible oils. Target analytes are separated from edible oil matrices using a two-step solid-phase extraction (SPE) procedure. The extracts are then analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI). Chromatographic conditions that separate sn-1 and sn-2 monoesters of 3-MCPD have been developed for the first time. The method has been validated for GEs, sn-1 3-MCPD monoesters of lauric, myristic, linolenic, linoleic, oleic, and stearic acids, and sn-2 3-MCPD monoesters of oleic and palmitic acids in coconut, olive, and palm oils using an external calibration curve. The range of average recoveries and relative standard deviations (RSDs) across the three oil matrices at three spiking concentrations are 84-115% (3-16% RSD) for the GEs, 95-113% (1-10% RSD) for the sn-1 3-MCPD monoesters, and 76.8-103% (5.1-11.2% RSD) for the sn-2 3-MCPD monoesters, with limits of quantitation at or below 30 ng/g for the GEs, 60 ng/g for sn-1 3-MCPD monoesters, and 180 ng/g for sn-2 3-MCPD monoesters.

Brevetoxin-3: Total assignment of the 1H and 13C NMR spectra at the submicromole level

Abstract The proton and carbon NMR spectra of the marine polyether toxin, brevetoxin-3, are totally assigned using a series of 2D NMR experiments which included: TOCSY, ROESY, HMQC, HMBC, and IDR-(Inverted Direct Response)-HMQC-TOCSY. All work was performed on a sample consisting of 800 μg (0.95 μmole) at 500 MHz.

Roridin l-2, a new trichothecene

The structure (2) of roridin L-2 is shown to be a C29-trichothecene that lacks the macrocyclic lactone system usually present in the roridins.

Structures of xanthoviridicatin D and xanthoviridicatin G, metabolites of penicillium viridicatum: application of proton and carbon-13 NMR spectroscopy

The structures of xanthoviridicatin D and xanthoviridicatin G, toxic metabolites of Penicillium viridicatum, have been shown to be 3 and 4a, respectively by spectroscopic studies.

Trichodermadiene: a new trichothecene

A new trichothecene, trichodermadiene (3), possessing a dienic ester side chain has been isolated and characterized.

A proposed standard sample for nuclear Overhauser effect measurements

A standard sample for the measurement of proton–proton nuclear Overhauser effects (NOE) is proposed. 1,5‐Dichloro‐2,4‐dimethoxybenzene (DCDMB) shows an essentially full (50%) enhancement of the proton H‐3 when the protons of the flanking methoxyl groups are saturated. The molecule is appropriate as a standard for the following reasons. The molecule is stable and easily synthesized. All the lines in the spectrum appear as singlets, so selective population transfer effects cannot obscure the NOE. The proton at position 6 provides a monitor of other relaxation mechanisms that would reduce the NOE. The NOE was verified by two complementary experiments. One is the standard technique of measuring the intensity with and without irradiation. A second method, based on spin–lattice relaxation rate experiments, provides unbiased data and gives an statistical estimate of the errors. Within experimental error, the NOE for DCDMB is 50%.

Sesquiterpenoid tropolone glycosides from Liriosma ovata.

Two new sesquiterpenoid tropolone glycosides, liriosmasides A (1) and B (2), along with two known compounds, secoxyloganin and oplopanpheside C, were isolated from a methanol extract of the roots of Liriosma ovata. The structures of 1 and 2 were elucidated by spectroscopic methods including 1D and 2D NMR and by high-resolution mass spectrometry involving an ultra-high-performance liquid chromatography-quadrupole-orbital ion trap mass spectrometric (UHPLC-Q-Orbitrap MS) method. Compound 1 showed weak inhibitory activity against HIV RNase H.

1H NMR Chemical Shifts and Coupling Constants of Some 3‐Monosubstituted 2‐Methylpropenes

1H NMR chemical shifts and proton–proton coupling constants for some 3‐substituted 2‐methylpropenes [YCH2C(Me)CH2, Y=H, Cl, Br, I, OH, OMe, OEt, SH, SMe, SEt, NMe2 and NEt2] are reported. Resonances of the olefinic protons were assigned through lanthanide‐induced shifts. Chemical shifts of the olefinic protons (HA and HB) showed a dependence on the substituent at C‐3 of the allylic fragment. Long‐range allylic coupling constants (4Jcisoid for HA and CH2 and HB and Me; 4Jtransoid for HB and CH2 and HA and Me) were determined by spectral expansion and simulation.

Spectroscopic Analysis of Wheat Fractions and Reconstituted Whole Wheat Mixtures by 1H-NMR and NIR

Commercial success of whole wheat products has warranted development of new analytical approaches for differentiating whole grain products from conventional food products made from refined grains. Here, we have analyzed three different wheat fractions (namely, bran, germ, and refined flour) of two wheat varieties. In addition, a whole wheat sample containing all three fractions was also included in the study to investigate the application of two spectral fingerprinting methods—proton nuclear magnetic resonance (1H-NMR) and near-infrared (NIR) spectroscopy—for differentiating the three fractions and the whole wheat. Results show that both these methods provide unique spectral fingerprints for the bran, germ, refined, and whole wheat flours. In addition, we were able to distinguish whole grain composed of different ratios of the germ, bran, and refined grain, exemplifying the potential applicability of both fingerprinting methods (NIR and NMR) for the differentiation of whole and refined wheat samples. Prin...