LiOtBu-Promoted trans-Stereoselective and ß-Regioselective Hydroboration of Propargyl Alcohols.

A convenient and efficient trans-stereoselective and ß-regioselective hydroboration of propargyl alcohols was achieved simply with LiOtBu as the base and (Bpin)2 as the boron reagent in dimethyl sulfoxide at room temperature. Both terminal and internal propargyl alcohols with diverse structures and functional groups underwent the transformation smoothly to produce ß-Bpin-substituted (E)-allylic alcohols, of which the synthetic potentials were demonstrated by the downstream conversions of boronate, alkenyl, and hydroxyl groups.

Stereoselective Dehydroxyboration of Allylic Alcohols to Access (E)-Allylboronates by a Combination of C-OH Cleavage and Boron Transfer under Iron Catalysis.

Iron-catalyzed direct SN2' dehydroxyboration of allylic alcohols has been developed to access (E)-stereoselective allylboronates. Allylic alcohols with diverse structures and functional groups, especially derived from natural products, underwent smooth transformation. The six-membered ring transition state formed by allylic alcohols and iron-boron intermediate was indicated to be the key component involved in transfer of the boron group, activation of the C-OH bond, and control of the stereoselectivity.

Phenolic compounds and antioxidant properties of wheat fermented with Agaricus brasiliensis and Agaricus bisporus.

Solid-state fermentation with Agaricus brasiliensis and Agaricus bisporus on whole grain wheat was carried out. Phenolic compounds and antioxidant properties of fermented wheat were determined. The results showed that the maximum values of polyphenols contents in wheat fermented with A. brasiliensis and A. bisporus reached, respectively (3.16 ± 0.21) and (3.93 ± 0.23) mg GAE/g, which were 2.90 and 3.61 times of unfermented control. By employing ultra performance liquid chromatography coupled to mass spectrometry (UPLC-MS), 18 kinds of phenolic compounds were identified from fermented wheat. Compared with control, only 4-hydroxy-benzaldehyde was the same compound. It indicated that fermentation with the two fungi changed polyphenols contents and phenolic compounds composition in wheat to a great extent. Among these phenolic compounds, except for 4-hydroxy-benzaldehyde, 4-hydroxy-benzoic acid and ß-N-(γ-glutamyl)-4-formylphenylhydrazine, other 15 kinds of phenolic compounds were first identified from mushroom samples (including fruit bodies, mycelia and fermentation products). DPPH radical scavenging capacity, reducing power, ferrous ion chelating ability and inhibition of lipid peroxidation of fermented wheat were significantly stronger than control (P < 0.05).

Effects of Selenium on Differentiation and Antioxidant Activity of Sclerotium of Penicillium thomii Q1 Strain.

Selenium is an essential trace element, which has certain antioxidant properties. Na2SeO3 is toxic, and its use is limited. SeMet, as an organic selenium, is less toxic than Na2SeO3. In this experiment, different concentrations of Na2SeO3 and SeMet were added to MEA and PDA media to observe the effect of selenium on the sclerotium differentiation of Q1 strain, and the contents of carotenoids, ascorbic acid, and total phenol and their reducing power, DPPH free radical scavenging ability, ferrous ion chelating ability, and superoxide anion scavenging ability were determined. Meanwhile, the orthogonal design was used to optimize the selenium enrichment culture conditions of Q1. The results showed that the addition of selenium in the PDA medium was not conducive to the differentiation of Q1 strain. The addition of inorganic and organic selenium in the MEA medium at different concentrations resulted in the accumulation of carotenoids, ascorbic acid, phenols, and selenium in the sclerotia of Q1 strain, and the contents of carotenoids, ascorbic acids, and selenium in the sclerotia of Q1 strain were increased to different degrees, but it cannot increase the content of total phenol. In addition, when the concentration of Na2SeO3 and SeMet in the medium was 10 µg/mL, the reducing power of the extract was improved. The experimental results can provide a new research idea for the utilization and development of Penicillium sclerotium and selenium.

Protein nutritional value, polyphenols and antioxidant properties of corn fermented with Agaricus brasiliensis and Agaricus bisporus.

Solid-state fermentation (SSF) with Agaricus brasiliensis and Agaricus bisporus on corn was carried out. The results showed that SSF with the two fungi made up the deficiency of tryptophan in corn and improved the protein nutritional value of corn. The conjugated polyphenols contents in fermented corn decreased and free polyphenols (FPP) contents increased. FPP contents in corn fermented with the two fungi reached respectively 25 and 88 times of control, total polyohenols contents reached respectively 1.4 and 3.3 times of control. The antioxidant properties (i.e. 1,1-diphenyl-2-picrylhydrazyl radical scavenging capacity, reducing power, ferrous ion chelating ability and superoxide anion radical scavenging ability) of fermented corn were improved significantly. SSF with A. bisporus was more favorable to the enhancement in protein nutritional value and antioxidant properties of corn than that of A. brasiliensis. The results indicated that SSF with the two fungi could upgrade the protein nutritional value, FPP content and antioxidant properties of corn.

Biosorption of Copper (II) from Aqueous Solutions by Sclerotiogenic Aspergillus oryzae G15.

This study aimed at investigating the biosorption of copper(II) from aqueous solutions by sclerotiogenic Aspergillus oryzae G15. Potentiometric titration analysis results indicated that carboxyl group was mainly responsible for Cu(II) adsorption. Sclerotia were a better biosorbent than mycelia, which could be ascribed to the higher amount of carboxyl sites exposed after differentiation. Langmuir isotherm model fitted well the absorption process of mycelia and sclerotia with the maximum theoretical sorption capacities of 35.34 and 73.53 mg/g, respectively. Scanning electron microscopy coupled with energy dispersive X-ray analysis confirmed that there was surface biosorption of Cu(II) on the adsorbents. Based on the fourier transform infrared spectroscopy analyses results, it could be proposed that the increased sorption capacity of sclerotia was due to increased functional groups related to the biosorption process. Cu(II)-loaded biosorbents could be regenerated and reused, which indicated that A. oryzae G15 could be considered as an alternative for removing Cu(II) from wastewater.

Tolerance and stress response of sclerotiogenic Aspergillus oryzae G15 to copper and lead.

Aspergillus oryzae G15 was cultured on Czapek yeast extract agar medium containing different concentrations of copper and lead to investigate the mechanisms sustaining metal tolerance. The effects of heavy metals on biomass, metal accumulation, metallothionein (MT), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were evaluated. Cu and Pb treatment remarkably delayed sclerotial maturation and inhibited mycelial growth, indicating the toxic effects of the metals. Cu decreased sclerotial biomass, whereas Pb led to an increase in sclerotial biomass. G15 bioadsorbed most Cu and Pb ions on the cell surface, revealing the involvement of the extracellular mechanism. Cu treatment significantly elevated MT level in mycelia, and Pb treatment at concentrations of 50-100 mg/L also caused an increase in MT content in mycelia. Both metals significantly increased MDA level in sclerotia. The variations in MT and MDA levels revealed the appearance of heavy metal-induced oxidative stress. The activities of SOD, CAT, and POD varied with heavy metal concentrations, which demonstrated that tolerance of G15 to Cu and Pb was associated with an efficient antioxidant defense system. In sum, the santioxidative detoxification system allowed the strain to survive in high concentrations of Cu and Pb. G15 depended mostly on sclerotial differentiation to defend against Pb stress.

Synthesis and activity evaluation of the cyclic dipeptides arylidene N-alkoxydiketopiperazines.

A series of arylidene N-alkoxydiketopiperazines was designed and stereoselectively synthesized via oxime-ether formation and intramolecular acylation. Possible cyclization and acid-catalyzed rearrangement-fragmentation mechanisms were discussed. The crystal structure of the novel diketopiperazine further confirmed the rearrangement mechanism. Most compounds exhibited antitumor activity. Several compounds were more potent against caspase-3. Specifically, compounds 6e, 6g, and 6f inhibited caspase-3 at IC50 values lying within the low micromolar range and demonstrated good selectivity. The binding modes of alkoxydiketopiperazines in the active center of caspase-3 were also discussed based on the molecular docking results.

Stereoselectively synthesis and structural confirmation of dehydrodipeptides with dehydrobutyrine.

Most of polypeptides containing α,ß-dehydroamino acids have important biological activity, so exploration of synthetic method has practical significance. In this paper, dipeptides were prepared from l-threonine by protecting of c-terminal allyl acetate, and condensing reaction with a series of N-Boc amino acid. Then, treatment of dipeptides obtained with DMAP, (Boc)2O and tetramethylguanidine in the acetonitrile occured ß-elimination reaction to yield stereoselectively dehydrodipeptides. Structures of dehydrodipeptides were confirmed by (1)H NMR, (13)C NMR and MS. Analysis of (1)H NMR, 2D NMR and crystal structure showed that the dehydrodipeptides were Z-configuration.Graphical abstractDehydrodipeptides were prepared from l-threonine. Their structures were confirmed by (1)H NMR, (13)C NMR and MS.

Synthesis and biological evaluation of open-chain analogs of cyclic peptides as inhibitors of cellular Shp2 activity.

A series of open-chain analogs of cyclic peptides was designed and synthesized using sansalvamide A as a model compound. All compounds exhibited low antitumor activity. Furthermore, the evaluation of their inhibitory potency toward IMPDH, SHP2, ACHE, proteasome, MAGL, and cathepsin B showed that all of the compounds were potent against protein tyrosine phosphatase Shp2. Specifically, compounds 1a, 1d, 2b, and 2f were found to inhibit SHP2 with IC50 values in the low micromolar range and good selectivity. Based on the molecular docking results, the binding modes of the chain cyclic peptides in the active center of SHP2 were discussed.

Effect of copper-induced oxidative stress on sclerotial differentiation and antioxidant properties of Penicillium thomii PT95 strain.

Penicillium thomii PT95 strain was able to form abundant orange, sand-shaped sclerotia in which carotenoids were accumulated. The aim of this work was to determine the effects of copper-induced oxidative stress on the sclerotial differentiation and antioxidant properties of PT95 strain. The results showed that the time of exudates initiation, sclerotial initiation and sclerotial maturation of PT95 strain were advanced in 1-2 days under the copper-induced oxidative stress growth conditions. The analytical results of sclerotial biomass, carotenoids content in sclerotia showed that copper-induced oxidative stress favored the sclerotial differentiation and biosynthesis of carotenoids. Under the copper-induced oxidative stress growth conditions, the total phenolics content and DPPH free radical scavenging activity of sclerotia of this fungus were decreased as compared with the control. However, the oxidative stress induced by a lower amount of CuSO4 in media could enhance significantly the reducing power of sclerotia.

Wet-plate culture studies of Penicillium sp. PT95 and Q1 for mass production of sclerotia.

Penicillium sp. PT95 and Q1 strains were able to form abundant orange, sand-shaped sclerotia in which carotenoids were accumulated. To determine the potential availability of the wet-plate method for mass production of sclerotia, nine kinds of liquid media were used culture the PT95 and Q1 strains. The results of the wet-plate culture showed that on 25% glycerol nitrate broth medium, the growth of both strains was relatively slow, and no sclerotia were found. Q1 strain cultured on Czapek's yeast extract broth medium could not form sclerotia. On other media, both strains could form sclerotia. For PT95 strain, the highest sclerotial biomass (380 mg plate(-1) ) and carotenoids yield (20.88 µg plate(-1) ) could be obtained on Czapek's yeast extract broth and Georgiou's liquid medium, respectively. For Q1 strain, malt extract broth medium gave the highest sclerotial biomass (340 mg plate(-1) ) and omitting iron Joham's liquid medium gave the highest carotenoids yield (18.29 µg plate(-1) ). The results from this study suggest the potential usage of wet-plate method in the mass production of sclerotia of the PT95 and Q1 strains.

Effect of copper-induced oxidative stress on sclerotial differentiation and antioxidants contents of Penicillium thomii Q1.

Penicillium thomii Q1 strain was able to form abundant orange, sand-shaped sclerotia in which carotenoids were accumulated. The aim of this work was to determine the effects of copper-induced oxidative stress on the sclerotial differentiation, biosynthesis of some endogenous antioxidants, and the activities of some antioxidative enzymes of Q1 strain. The results showed that the oxidative stress induced by copper was clearly dependent on the CuSO4 concentrations in media, and characterized by the initiation of lipid peroxidation. Under the copper-induced oxidative stress conditions, the time of exudates initiation, sclerotial initiation and sclerotial maturation of Q1 strain were advanced in 1-2 days. The analytical results of sclerotial biomass, carotenoids, and ascorbate contents showed that copper-induced oxidative stress favored the sclerotial differentiation and biosynthesis of carotenoids and ascorbate. The oxidative stress induced by a lower amount of CuSO4 in media could enhance significantly the superoxide dismutase and catalase activities of Q1 strain.

3-(3,4-Dihydroxyphenyl)-1-methoxy-1-oxopropan-2-aminium chloride.

In the title compound, C(10)H(14)NO(4) (+)·Cl(-), the benzene ring makes a dihedral angle of 64.68 (4)° with the methyl-amino-propano-ate unit, which is bonded to the catechol ring via a methyl-ene C atom. A strong intra-molecular O-H⋯O hydrogen bond occurs. In the crystal, O-H⋯O, N-H⋯Cl and O-H⋯Cl hydrogen bonds and weak C-H⋯O inter-actions link the mol-ecules into a three-dimensional network.

Isolation and characterization of a Chinese strain of human enterovirus 74 from a healthy child in the Tibet Autonomous Region of China.

Human enterovirus 74 (HEV74) is a recently described serotype within the species Human enterovirus B (HEV-B). Few nucleotide sequences of HEV74 are available, and only one complete genome sequence (the prototype strain) has been published. In this study, we report the complete genome sequence of an HEV74 strain isolated from a healthy child during a stool survey in the Tibet Autonomous Region of China. The results indicated that HEV74 may be a prevalent and common enterovirus type, and that HEV74 is globally distributed, especially in Asia. Sequence analysis revealed high variability among HEV74 strains and indicated frequent recombination within HEV-B.

Stereoselective synthesis and rearrangement-fragmentation of arylidene N-alkoxydiketopiperazines.

A stereoselective synthesis of arylidene N-alkoxydiketopiperazines via oxime-ether formation and intramolecular acylation is described, followed by an acid-catalysed rearrangement-fragmentation to give novel diketopiperazine hemiaminal derivatives with useful bioactivity against certain tumour cell lines.

(Anthracen-9-ylmeth-yl)benzyl-ammonium chloride.

In the title compound, C(22)H(20)N(+)·Cl(-), the anthracene system makes a dihedral angle of 72.65 (4)° with the benzene ring. The C-N-C-C torsion angles in the chain connecting the benzene ring and anthracene system are 52.24 (15) and -170.73 (11)°. The crystal structure is stabilized by inter-molecular N-H⋯Cl and C-H⋯Cl hydrogen bonds, which link the mol-ecules into tetra-mers about inversion centers.

Influence of oxidative stress and grains on sclerotial biomass and carotenoid yield of Penicillium sp. PT95.

Oxidative stress and grains were evaluated for carotenoid production by solid-state fermentation using Penicillium sp. PT95. When the fungus was grown at high oxidative stress, its sclerotial biomass and carotenoid content in sclerotia increased significantly with respect to low oxidative stress (P < 0.01). High oxidative stress also caused a statistically significant increase in carotenoid yield as compared with low oxidative stress (P < 0.01). Both the sclerotial biomass and the amount of carotenoid accumulated in sclerotia of strain PT95 were strongly dependent on the grain medium used. Among the grain media tested under high oxidative stress, buckwheat medium gave the highest content of carotenoid in sclerotia (828 microg/g dry sclerotia), millet medium gave respectively the highest sclerotial biomass (12.69 g/100 g grain) and carotenoid yield (10.152 mg/100 g grain).

Dimethyl 2-(2-quinolylmeth-yl)malonate.

In the title compound, C(15)H(15)NO(4), the quinoline ring system and one of the malonate side chains are essentially coplanar (r.m.s. deviation = 0.0297 Å). The two malonate C-C(=O)-O-CH(3) side chains are oriented at right angles [89.68 (8)°] with respect to each other. The crystal packing is stabilized by weak non-classical inter-molecular C-H⋯O hydrogen bonds, which link the mol-ecules into dimers about inversion centers.

Dimethyl 2-(2,4,6-trimethoxy-benz-yl)malonate.

In the title compound, C(15)H(20)O(7), the benzene ring makes dihedral angles of 69.17 (5) and 80.81 (4)° with the two side chains of malonate. The two malonate side chains comprising C/C/O/C atoms are oriented at right angles [86.26 (6)°] with respect to each other. In the crystal structure, the crystal packing is stabilized by weak non-classical inter-molecular C-H⋯O hydrogen bonds, which link the mol-ecules into an infinite network.