2-naphthylacetic Acid Research Articles

Novel ferrofluid based on water-based deep eutectic solvents: application in dispersive liquid-liquid microextraction of naphthalene-derived plant growth regulators in edible oil

A new ferrofluid extractant (Fe3O4 @SiO2-WDES) was ingeniously prepared by coating magnetic Fe3O4 @SiO2 microspheres with water-based deep eutectic solvent (WDES) and used for dispersive liquid-liquid microextraction (DLLME) and HPLC determination of naphthalene-derived plant growth regulators (PGRs, i.e., 1-naphthylacetic acid, 2-naphthylacetic acid, 1-naphthoxy acetic acid, 2-naphthyloxyacetic acid and 1-naphthylacetamide) in edible oil. Herein, mass transfer of the analytes in DLLME was significantly enhanced via increasing the contact surface by employing the microspheres as the supporter and dispersant of WDES, and phase separation can be efficiently achieved using an external magnet rather than centrifugation in traditional DLLME. Response surface methodology (RSM) based on Box-Behnken design (BBD) was employed for the optimization of core experimental conditions, and Analytical Eco-Scale and Analytical GREEnness Metric Approaches were adopted to evaluate the degree of greenness of the procedure. Under the optimal conditions, satisfactory performances of linearity ranged from 5 to 100 μg/L (R2 ≥ 0.9982), limit of detection (0.58–0.91 μg/L), limit of quantitation (1.9–3.0 μg/L), precision (RSDs ≤ 5.5%), recovery (81.3%−108.1%) and negligible matrix effect were achieved, which introduced a promising alternative route for the determination of naphthalene-derived plant growth regulators in edible oil.

A novel electronic assay based on a sol-gel transition reaction and a thin-film transistor of supramolecular hydrogels to detect alkaline phosphatase activity

Abstract Herein, we developed an extended floating-gate thin-film transistor (EFG-TFT) together with various sol-gel phases to determine alkaline phosphatase (ALP) activity. The EFG-TFT was fabricated with ZnO as the channel material and YOX as the dielectric layer, which provided an extended area for sensing the analyte interacting with the designed hydrogelator. A peptide-based supramolecular hydrogel material, i.e., 2-naphthylacetic acid- l -phenylalanine- l -phenylalanine- l -O-phosphor tyrosine (named Nap-FF-Yp) was synthesized as our sensing platform to detect ALP activity and the sol-gel state. Nap-FF-Yp could be cleaved by ALP during hydrolysis, leading to π-π stacking, and finally changed to a hydrogel. Due to the difference in the potential drop between the liquid phase and gel phase of the hydrogel, the sol-gel transition reaction could be monitored by the electrical signal. The greater the extent of hydrogelation, the smaller the threshold voltage (Vth) variation, and the threshold voltage shifted to the left. Under the device’s optimal conditions with oxygen plasma treatment, the limit of detection (LOD) reached 0.024 U/L. The development of this novel sol-gel state for a high-speed screening sensing platform with an excellent electrical response demonstrates the potential capabilities of future high-speed response sensors.

Monodispersed mesoporous SiO2@metal-organic framework (MSN@MIL-101(Fe)) composites as sorbent for extraction and preconcentration of phytohormones prior to HPLC-DAD analysis.

The monodispersed mesoporous SiO2@metal-organic framework (MSN@MIL-101(Fe)) composites were prepared by grafting MSN-NH2 onto MIL-101(Fe) particles with a solvothermal method. The adsorption ability of thecomposites was greatly improved compared to that of pristine MSNs or MIL-101(Fe) for phytohormones (Phys). The MSN@MIL-101(Fe) composites were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, energy dispersive spectrometer, and mapping analysis. Using MSN@MIL-101(Fe) composites as sorbent, a dispersive solid-phase extraction procedure (dSPE) was developed to extract three endogenous Phys (abscisic acid (ABA), indole-3-aceticacid (IAA), and indole-3-butyric acid (IBA)) and two exogenous Phys (1-naphthylacetic acid (1-NAA) and 2-naphthylacetic acid (2-NAA)) prior to HPLC-DAD analysis. The experimental parameters including sample volume, sorbent amount, adsorption time, adsorption pH, desorption time, and desorption solvent on extraction efficiency were optimized and evaluated. Under optimized conditions, the working range of 0.08 to 0.45ngmL-1 with enrichment factors from 144 to 207 were achieved. The linear range is0.75-200ngmL-1 for IAA, 0.20-200ngmL-1 for ABA, and1.0-200ngmL-1 for IBA, 1-NAA, and 2-NAA. With MSN@MIL-101(Fe) as sorbent for extraction of Phys and determinationby HPLC-DAD, two endogenous Phys (IAA and ABA) were detected from mung bean sprouts which were made in a laboratory, and the results were further confirmed by high-resolution mass spectrometry. The composites can be applied to extract other small molecules, which have similar chemical structures with Phys in biological, environmental, and food samples. Graphical abstract Schematic presentation of a dispersive solid-phase extraction using monodispersed mesoporous SiO2@metal-organic framework composites (MSNs@MIL-101(Fe)) as the sorbent for extraction, clean-up, and preconcentration of phytohormones in mung bean sprouts prior to HPLC-DAD analysis.

An efficient one-pot synthesis of polyphenolic amino acids and evaluation of their radical-scavenging activity

A simple and efficient procedure for the synthesis of N-acyl 4-hydroxy, 4-hydroxy-3-methoxy and 3,4-dihydroxy phenylglycine amides by a strategy based on the multicomponent Ugi reaction is proposed. Hydroxybenzaldehyde derivatives were reacted with 4-methoxybenzylamine, cyclohexyl isocyanide and benzoic acid or 2-naphthylacetic acid to give Ugi adducts that were treated with trifluoroacetic acid yielding N-acyl hydroxyphenylglycine amides in good yields. The same procedure using as acid component protocatechuic acid or hydrocaffeic acid gave N-catechoyl 3,4-dihydroxyphenylglycine amides. The use of N-benzyloxycarbonylglycine as acid component allowed the preparation of a 3,4-dihydroxyphenylglycyl dipeptide derivative. Radical-scavenging activity studies of the polyphenolic amino acid derivatives showed a sharp increase in activity with the increase in number of hydroxyl or catechol groups present. Cyclic voltammetry experiments established a correlation between oxidation peak potentials and the radical-scavenging activity.

Determination of Five Plant Growth Regulator Containing Carboxyl in Bean Sprouts Based on Chemical Derivatization by GC-MS

An efficient and sensitive analytical method for the simultaneous determination of five plant growth regulators (PGRs) has been successfully developed, including 3-Indoleacetic acid (IAA), 2-Naphthylacetic acid (2-NAA), Beta-indolebutyric acid (IBA), 2-(2,4-dichlorophenoxy), acetic acid (2.4-D), and 4-Chlorophenoxyacetic acid (4-CPA) in bean sprouts. Using 10% boron trifluoride of methanol as the derived reagent and the reaction was derivatized at 70 °C for 30 min, the derivatives of five PGRs have been completely separated within 19 min. It has a linear relationship in the concentration range of 0.01–0.20 mg/kg and the correlation coefficients (r2) in excess of 0.997. The average recoveries were ranged from 72.7–98.6% at three spiking different concentration levels of 0.05, 0.10, and 0.15 mg/kg, respectively. The relative standard deviations (RSDs) were ranged from 1.2 to 9.0%. The limits of detection and the limits of quantification were ranged from 0.00024 to 0.00172 mg/kg and 0.0008–0.0052 mg/kg, respectively. On the basis of these, the measurement has been successfully applied to the analysis of the exogenous phytohormones in the bean sprouts. Except for 4-CPA and IAA, the rest of the analytes were undetected in samples. In sum, the current method can be used for accurate determination and confirmation of PGRs in many other crops, such as bean sprouts.

New method of synthesis of 2-naphthylthioacetamides from 4-(2-naphthyl)-1,2,3-thiadiazole

Piperidylamide [1] and morpholylamide [2] of 2naphthylthioacetic acid and their derivatives have been well known. Piperidylamide of 2-naphthylthioacetic acid can be obtained by the Willgerodt–Kindler reaction [1] from 2-acetylnaphthalene, sulfur and pipridine or by treating piperidylamide of 2-naphthylacetic acid with Lawesson reagent [3]. Morpholylamide of 2naphthylthioacetic acid can be obtained only by the Willgerodt–Kindler reaction [2, 4].

Syntheses, structures, and photochemical properties of (μ3-O)tris{bis(μ-carboxylato)}trimanganese complexes with naphthylacetate ligands with relevance to artificial solar energy-harvesting systems

Two new trinuclear Mn complexes containing naphthalene moieties, [Mn3(μ3-O)(μ-O2CCH2-1-naph)6(py)3] (1) and [Mn3(μ3-O)(μ-O2CCH2-2-naph)6(py)3] (2) (naph-1-CH2CO2H=1-naphthylacetic acid, naph-2-CH2CO2H=2-naphthylacetic acid, py=pyridine), were synthesized. The X-ray crystallography of 1, the EXAFS analyses of 1 and 2, and the magnetic susceptibility data for these complexes showed that they are trinuclear complexes containing a [Mn3(μ3-O)(μ-O2CR)6] core with mixed-valence Mn3(II, III, III) centers. CVs exhibited an oxidation peak ascribed to MnIII3/MnIIMnIII2 and a reduction peak ascribed to MnIIMnIII2/MnII2MnIII in CH2Cl2. In the fluorescence spectra, the fluorescence intensities of 1 and 2 were smaller than those of the naphthylacetic acids and depended on the dielectric constant of solvent. These results suggested that there is electron transfer between the manganese centers and the naphthyl moieties. The fluorescence decays of 1 and 2 in CH3CN were also faster than the decays in the toluene solutions; this result parallels the lower intensity of the static fluorescence spectra in solvents with a higher dielectric constant. The fluorescence decay curves of 1 and 2 were fitted by two lifetimes, τ1 and τ2, suggesting that electron transfer occurs from the monomer (τ1) and the excimer (τ2) of the naphthyl moieties to the manganese center.

A theoretical model for polarized infrared spectra of crystals of 2-naphthyl acetic acid in the OH-stretching region

This paper presents results of a theoretical study on νO-H(D) band shapes in the polarized infrared spectra of 2-naphthylacetic acid (2-NA) crystals measured at the temperature of liquid nitrogen. The line shapes were studied within the frameworks of strong anharmonic coupling, Davydov coupling, Fermi resonance coupling, direct and indirect damping, and a selection rule breaking mechanism for forbidden transitions in IR. The present approach correctly fits the experimental line shape of the hydrogenated compound and predicts satisfactorily the evolution in the line shapes with isotopic substitution. Numerical calculations show that mixing of all these effects allows one to reproduce satisfactorily the main features of the experimental IR line shapes of hydrogenated and deuterated 2-NA crystals and is expected to confirm the importance of the Fermi resonances in reproducing the experimental spectra.

Inclusion compounds of plant growth regulators in cyclodextrins, part VII: study of the crystal structures of 2-naphthylacetic acid encapsulated in β-cyclodextrin and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin complexes by X-ray crystallography

The crystal structures of the β-naphthylacetic acid (2NAA)/β-cyclodextrin (β-CD) and the 2NAA/heptakis(2,3,6-tri-O-methyl)-β-CD (TMβCD) complexes are reported. The 2NAA/β-CD complex crystallizes in the triclinic system forming a dimer inside the cavity of which two 2NAA molecules disordered over two sites are located. The dimers are stacked along the c axis according to the channel packing mode forming a nanotube which resembles a wireway as it contains guest molecules linked by π–π interactions inside each dimeric cavity and by H-bonds between the adjacent dimers. The 2NAA/TMβCD complex crystallizes in the orthorhombic space group P212121. Its asymmetric unit contains one host, one guest distributed over two sites and one water molecule having a low occupancy factor. The complexes are packed in a head-to-tail mode forming a screw channel along the b axis. The carboxyl group of the guest protrudes towards the “free” space between the complexes and is H-bonded to the water molecule which in turn is H-bonded to the O5n atom of the host of the subsequent complex. The orientation of the guest molecule in the 2NAA/β-CD complex has been found opposite to that of the guest in the 2NAA/TMβCD complex probably due to the formation of dimers and the π–π interactions between the naphthalene moieties of the encapsulated molecules inside the dimeric cavity.

Site‐specific carbon isotope analysis of aromatic carboxylic acids by elemental analysis/pyrolysis/isotope ratio mass spectrometry

Site-specific carbon isotope composition of organic compounds can provide useful information on their origin and history in natural environments. Site-specific isotope analyses of small amounts of organic compounds (sub-nanomolar level), such as short-chain carboxylic acids and amino acid analogues, have been performed using gas chromatography/pyrolysis/isotope ratio mass spectrometry (GC/pyrolysis/IRMS). These analyses were previously limited to volatile compounds. In this study, site-specific carbon isotope analysis has been developed for non-volatile aromatic carboxylic acids at sub-micromolar level by decarboxylation using a continuous flow elemental analysis (EA)/pyrolysis/IRMS technique. Benzoic acid, 2-naphthylacetic acid and 1-pyrenecarboxylic acid were pyrolyzed at 500-1000 degrees C by EA/pyrolysis/IRMS to produce CO2 for delta13C measurement of the carboxyl group. These three aromatic acids were most efficiently pyrolyzed at 750 degrees C. Conventional sealed-tube pyrolysis was also conducted for comparison. The delta13C values of CO2 generated by the continuous flow technique were within 1.0 per thousand of those performed by the conventional technique, indicating that the new continuous flow technique can accurately analyze the carbon isotopic composition of the carboxyl group in aromatic carboxylic acids. The new continuous flow technique is simple, rapid and uses small sample sizes, so this technique will be useful for characterizing the isotopic signature of carboxyl groups in organic compounds.

Structure and Photochemical Properties of (μ-Alkoxo)bis(μ-carboxylato)diruthenium Complexes with Naphthylacetate Ligands

Two new dinuclear Ru(III) complexes containing naphthalene moieties, K[Ru2(dhpta)(mu-O2CCH2-1-naph)2] (1) and K[Ru2(dhpta)(mu-O2CCH2-2-naph)2] (2) (H5dhpta = 1,3-diamino-2-hydroxypropane-N,N,N',N'-tetraacetic acid, naph-1-CH2CO2H = 1-naphthylacetic acid, naph-2-CH2CO2H = 2-naphthylacetic acid), were synthesized. Complex 2 crystallized as an orthorhombic system having a space group of Pbca with unit cell parameters a = 10.6200(5) A, b = 20.270(1) A, c = 35.530(2) A, and Z = 8. EXAFS analysis of 1 and 2 in the solid states and in solution clarified that the dinuclear structures of 1 and 2 were kept in DMSO solutions. Variable-temperature magnetic susceptibility data indicated that the two Ru(III) centers are strongly antiferromagnetically coupled as shown by the large coupling constants, J = -581 cm(-1) (1) and -378 cm(-1) (2). In the cyclic voltammograms of 1 and 2, one oxidation peak and two reduction peaks which were assigned to the redox reaction of the ruthenium moieties were observed in DMF. The large conproportionation constants estimated from the reduction potentials of Ru(III)Ru(III) and Ru(III)Ru(II) indicated the great stability of the mixed-valent state. The mixed-valent species [Ru(III)Ru(II)(dhpta)(mu-O2CCH2-R)2](2-) (R = 1-naph (6) and R = 2-naph (7)) were prepared by controlled potential electrolysis of 1 and 2 in DMF. The electronic absorption spectra of 6 and 7 were similar to that of [Ru(III)Ru(II) (dhpta)(mu-O2CCH3)2](2-) which is a typical Class II type mixed-valent complex. The fluorescence decay of 1 and 2 indicated that there are two quenching processes which come from the excimer and monomer states. The short excimer lifetimes of 1 and 2 were ascribed to the energy transfer from the naphthyl moieties to the Ru centers. The different excimer ratio between 1 and 2 suggested that the excimer formation is affected by the conformation of the naphthyl moieties in the diruthenium(III) complexes.

Growth-regulating activity of N-benzyl- and O-benzyl-containing compounds belonging to a new group of synthetic analogues of natural auxins

We studied the effect of benzylamine, benzyl alcohol, and their derivatives (constituting a new group of synthetic analogues of natural auxins) on rooting of leaf and stem cuttings, rhizogenesis and growth of barley plantlets and tomato seedlings, and tomato plant productivity. These compounds promoted rooting of leaf and stem bean cuttings, increased rhizogenic activity, and stimulated the development of root systems in barley and tomato seeds. The activity of the compounds studied was similar to that of standard substances (3-indoleacetic acid potassium salt and 2-naphthylacetic acid). The benzyl group attached to the oxygen or nitrogen atom was shown to be the smallest molecular structure which provided auxin activity of the compounds. Derivatives of benzyl alcohol containing the quaternary ammonium fragment possessed auxin and anti-gibberellin (retardant) properties. They were selected by chemical synthesis of low-molecular-weight bioregulators with desired properties (a combination of chemical fragments with complementary physiological activity in the molecule). Auxin and anti-gibberellin (retardant) activities produced a synergistic effect. Germination of seeds treated with these compounds was accompanied by a more significant increase in the weight and length of roots (compared to standard auxins). The rate of seedling establishment reached 100%. The development of fruits and accumulation of reserve nutrient substances were synchronized and accelerated after spraying vegetating plants with solutions of studied compounds. The synergistic effect underlay a significant increase in the amount and quality of the crop (e.g., tomatoes).

The energetics of naphthalene derivatives, III: phenylacetic acid and the isomeric 1- and 2-naphthylacetic acids

Phenylacetic acid and the isomeric 1- and 2-naphthylacetic acids are at the confluence of diverse concepts, techniques and classes of organic compounds. Summing the results of our new enthalpy of formation of the gaseous phenylacetic acid reported herein, and of literature enthalpy of formation of the isomeric solid naphthylacetic acids and of our new sublimation enthalpies reported herein, we derive gas phase enthalpies of formation of −314.7±3.1, −246.9±2.0 and −247.4±2.1kJmol−1 respectively. This corresponds to 1- and 2-naphthylacetic acid having indistinguishable enthalpies of formation. We also performed MP2(full)/6-31G(d) calculations on these species, resulting in enthalpies of formation of −307.3±0.8, −247.4±3.4 and −247.5±3.4kJmol−1 for phenylacetic acid and 1- and 2-naphthylacetic acid in satisfactory agreement with the above experimental results.

The functional role of threonine-205 in the mechanism-based inactivation of P450 2B1 by two ethynyl substrates: the importance of the F helix in catalysis.

We have previously demonstrated that substituting Val for Thr-205 in P450 2B1 abolishes the 16beta-hydroxylation of testosterone and markedly decreases the ability of 2-ethnylnaphthalene (2EN) and 17alpha-ethynylestradiol (17EE) to inactivate P450 2B1. The role of Thr-205 has been further investigated by measuring the kinetics of the mechanism-based inactivation of the 7-ethoxy-(trifluoromethyl)coumarin deethylation activity of 2B1 by 2EN and 17EE in wild-type (WT) and mutant P450s. In general, the kinetics of the inactivation of the Ser and Ala mutants was not significantly altered compared with WT. In contrast, the efficiency of the inactivation of the Val mutant decreased by approximately 6- and approximately 30-fold for 2EN and 17EE, respectively. High-pressure liquid chromatography (HPLC) analysis and SDS gel electrophoresis demonstrated the covalent binding of radiolabeled 2EN- and 17EE-reactive intermediates to the WT apoprotein, but not the Val mutant. The Val mutant was able to metabolize 2EN to 2-naphthylacetic acid, except the initial rate was slower than the WT. HPLC analysis of the 17EE incubation mixtures revealed three major metabolites and showed a correlation between the efficiency of inactivation and the generation of one of the major metabolites (C). Metabolite C was generated by the WT, Ser mutant, and Ala mutant. Metabolite C may be formed by the oxidation of the ethynyl group, and this reactive intermediate contributes to the inactivation of P450 2B1 by 17EE. The site-specific mutation of one residue, Thr-205 to Val, is sufficient to alter the profile of products formed during 17EE metabolism, such that very low levels of metabolite C are formed and inactivation is essentially abolished.

Polarization IR spectra of the hydrogen bond in 1-naphthylacetic and 2-naphthylacetic acid crystals: H/D isotopic effects. Temperature and polarization effects

This paper deals with experimental studies and with the quantitative interpretation of the polarized IR crystalline spectra of 1-naphthylacetic and 2-naphthylacetic acid. The spectra were measured in the ν O–H and in the ν O–D band frequency ranges, at the temperatures of 298 and 77 K. The intensity distribution in the bands was quantitatively reproduced on the basis of the strong-coupling model, when assuming that the isolated (COOH) 2 and (COOD) 2 cycles were the source of the spectral properties of the crystals. Such approach appeared to be sufficient for explaining most of the isotopic and the temperature effects in the spectra. A vibronic mechanism, promoting the symmetry forbidden transition in the IR, for the totally symmetric proton stretching vibrations in centrosymmetric hydrogen bond dimers, was found to be of a considerably minor importance, when compared with analogous spectral properties of arylcarboxylic acid crystals. Also no Fermi resonance impact on the ν O–H band shape was identified in the 1-naphthylacetic and 2-naphthylacetic acid crystal spectra. These effects were ascribed to weakening of electronic couplings between the hydrogen bonds and the phenyl rings, due to the separation of these molecular fragments by methylene groups in 1-naphthylacetic and 2-naphthylacetic acid molecules.

Identification and quantification of polar naphthalene derivatives in contaminated groundwater of a former gas plant site by liquid chromatography–electrospray ionization tandem mass spectrometry

A liquid chromatography (LC) method followed by electrospray ionization (ESI) and tandem mass spectrometry (MS–MS) was developed for the quantification of acidic naphthalene derivatives in the concentration range 0.1 to 100 μg/l without excessive sample preparation. For optimal sensitivity the LC–MS–MS measurements were performed recording mass fragmentation by collision induced dissociation in the multiple reaction mode. The collision energy was optimized for every analyte. The matrix effects of the sample were investigated by spiking standards of 1-naphthoic acid with humic acid (HA) and with calcium chloride. While HA decreased the signal intensity an increase was observed in the presence of calcium chloride. For the investigated groundwater samples of a tar oil contaminated site a complete separation of the analytes from the sample matrix by reversed-phase separation could be obtained. The absence of matrix effects on quantification results was confirmed by comparison of results based on external calibration with those based on standard addition of the analytes to a groundwater sample. In four groundwater samples of the contaminated site naphthalene derivatives like 1-naphthoic acid, 2-naphthoic acid, 1-naphthylacetic acid, 2-naphthylacetic acid, 1-hydroxy-2-naphthoic acid, 2-hydroxy-3-naphthoic acid, and naphthyl-2-methylenesuccinic acid have been detected.

Photodimerization of 2-pyridone in cocrystals with carboxylic acids using the stacking effect of naphthalene rings

During the crystalline-state photoreaction of 2-pyridone–carboxylic acid cocrystals, the 2-pyridone moieties were dimerized in the cocrystal with 2-naphthylacetic acid due to a stacking structure with a carbon-to-carbon distance appropriate for [4 + 4] cycloaddition.

Determination of Absolute Configurations of Tertiary Alcohols by NMR Spectroscopy

Abstract A method has been developed for determining the absolute configurations of acyclic tertiary alcohols using their 2NMA [methoxy-(2-naphthyl)acetic acid] esters. The 1H NMR spectra of (R)- and (S)-2NMA esters of model compounds were measured, and Δδ values (δR-ester − δS-ester) were calculated. The absolute configuration for tertiary hydroxy group is determined based on the sign of Δδ values like that for secondary hydroxy group.

Mechanism-based inhibition of mouse P4502b-10 by selected arylalkynes

Suicide inhibitors of cytochrome P450 families are excellent tools to predict which isoforms mediate the metabolism/activation of a variety of chemical agents. We compared the inhibitory effects of several arylalkynes on mouse cytochromes P450 with published data for the rat model. The inhibition of P4502b specific dealkylation of benzyloxyresorufin by 2-ethynylnaphthalene (2-EN), 5-phenyl-1-pentyne (PPY), 4-phenyl-1-butyne (PBY), and 9-ethynylphenanthrene (9-EPh) was measured in hepatic microsomes from male mice treated with 1,4-bis[2-(3,5-dichloropyridyloxy)]-benzene (TCPOBOP) to induce cytochrome P4502b. Pulmonary microsomes were prepared from untreated mice. 9-EPh, 2-EN, and PPY caused a time-, concentration-, and NADPH-dependent loss in P4502b activity in both tissues. PBY, however, demonstrated this type of inhibition only in liver microsomes. The ic 50 was calculated for both liver and lung microsomes and compared with published K i (concentration required for half-maximal inhibition) or K I (concentration required for halfmaximal inactivation) values for the rat. PPY, PBY, and 9-EPh were equally effective inhibitors of mouse P4502b and rat P4502B1. 2-EN was a 5- to 10-fold less potent inhibitor of mouse P4502b, as compared with the rat, even though it was shown to bind to the active site of the mouse isoform as demonstrated by its metabolism to 2-naphthylacetic acid. These data suggest that the active site of the mouse P4502b enzyme is functionally similar to the rat P4502B isoform, with the exception of the disparity in its susceptibility to inactivation by 2-EN as measured by the K i ; values.

Determination of the absolute configuration of yessotoxin, a polyether compound implicated in diarrhetic shellfish poisoning, by NMR spectroscopic method using a chiral anisotropic reagent, methoxy-(2-naphthyl)acetic acid

The absolute configuration of yessotoxin ( 1), a potent diarrhetic toxin causative of shellfish poisoning, was determined by NMR-spectroscopy using a chiral anisotropic reagent, methoxy-(2-naphthyl)acetic acid (2NMA), which was applied to a monoacetate of bisdesulfated yessotoxin ( 3).