Short Total Synthesis of (+)-Colletotryptins B-D and Mucronatin B Derivative.

The short and first total synthesis of (+)-colletotryptins B-D, ent-colletotryptin A, and diastereomer of mucronatin B, which are a group of natural 3-(indol-2-yl)-3-(indol-3-yl)-1,2-propanediol (IIPDO) analogues containing two stereogenic centers at the C8' and C9' positions, isolated from endophytic fungus Colletotrichum sp. SC1355 and Tetrapterys mucronata, respectively, has been successfully accomplished in two and three steps with overall yields ranging from 28 to 54%. Key features of this synthesis include an innovative Bi(OTf)3-catalyzed stereoselective transindolylation of (S)-3,3'-di(1H-indol-3-yl)propane-1,2-diol. The operational simplicity, environmentally friendly catalyst, and broad functional group tolerance of this modular strategy render it suitable for adoption in both academic and industrial settings.

Diastereoselective Addition of PhSCF2SiMe3 to Chiral N-tert-Butanesulfinyl Ketimines Derived from Isatins: Synthesis of Enantioenriched gem-Difluoromethylenated Spiro-pyrrolidinyl and Spiro-piperidinyl Oxindoles.

A convenient and efficient synthetic strategy to prepare enantioenriched gem-difluoromethylenated spiro-pyrrolidinyl and spiro-piperidinyl oxindoles is described. Fluoride-mediated diastereoselective nucleophilic addition of PhSCF2SiMe3 to chiral N-tert-butanesulfinyl ketimines derived from isatins was a key step and provided diastereomeric adducts, which were readily separable. Removal of the chiral sulfinyl group followed by structural manipulation afforded chiral gem-difluoromethylenated spiro-pyrrolidinyl and spiro-piperidinyl oxindoles.

Trichothecenes from a Soil-Derived Trichoderma brevicompactum.

Six new (1-6), together with seven known (7-13), trichothecenes were isolated from the soil-derived Trichoderma brevicompactum PSU-RSPG27. Their structures were established using spectroscopic data. The structure of 1 was confirmed by X-ray data. Trichodermin (7) exhibited the most potent activity against Plasmodium falciparum (K1 strain) with an IC50 value of 0.1 µM, while other trichothecenes (1, 8, 9, and 12) were much less active, with IC50 values in the range of 7.1-9.6 µM. Compound 7 displayed activity against noncancerous Vero cells with an IC50 value of 0.4 µM. The remaining compounds showed moderate to weak activity, with IC50 values in the range of 6.9-15.3 µM. Compounds 7 and 12 were active against human oral carcinoma (KB) cells with IC50 values of 2.4 and 3.7 µM, respectively. Additionally, compounds 7 and 12 displayed antifungal activity against Candida albicans with the respective MIC values of 1 and 2 µg/mL and were active against Cryptococcus neoformans with equal MIC values of 4 µg/mL.

Asperidines A-C, pyrrolidine and piperidine derivatives from the soil-derived fungus Aspergillus sclerotiorum PSU-RSPG178.

One new pyrrolidine derivative, asperidine A (1), and two new piperidine derivatives, asperidines B (2) and C (3), were isolated from the soil-derived fungus Aspergillus sclerotiorum PSU-RSPG178 together with two known alkaloids. Compound 3 possessed an unprecedented 7-oxa-1-azabicyclo[3.2.1]octane skeleton with four chiral centers. Their structures were determined by spectroscopic evidence. The absolute configurations of compounds 2 and 3 were established using Mosher's method and further confirmed for compound 3 by X-ray crystallographic data. Compound 2 dose-dependently inhibited the CFTR-mediated chloride secretion in T84 cells with an IC50 value of 0.96 µM whereas 3 displayed the same activity with the IC50 value of 58.62 µM. Compounds 2 and 3 also significantly reduced intracellular ROS under both normal and H2O2-treated conditions compared with their respective controls in a dose-dependent manner without cytotoxic effect on Caco-2 cells. In addition, compound 3 was inactive against noncancerous Vero cells whereas compound 2 was considered to be inactive with the IC50 value of >10 µM.

Lovastatin Analogues from the Soil-Derived Fungus Aspergillus sclerotiorum PSU-RSPG178.

Three new lovastatin analogues (1, 4, and 5) together with four known lovastatin derivatives, namely, lovastatin (2), α,ß-dehydrolovastatin (3), α,ß-dehydrodihydromonacolin K (6), and α,ß-dehydro-4a,5-dihydromonacolin L (7), were isolated from the soil-derived fungus Aspergillus sclerotiorum PSU-RSPG178. Their structures were established using spectroscopic evidence. Compound 5 exhibited the most potent activity against HMG-CoA reductase, with an IC50 value of 387 µM. In addition, the present study indicated the direct interaction of compound 5 with HMG-CoA reductase. Compound 5 was considered to be noncytotoxic against noncancerous Vero cells, with an IC50 value of 40.0 µM, whereas compound 2 displayed much stronger activity, with an IC50 value of 2.2 µM.

Asymmetric synthesis of gem-difluoromethylenated linear triquinanes via cascade gem-difluoroalkyl radical cyclization.

An asymmetric synthesis of gem-difluoromethylenated linear triquinanes is described exploiting the synthetic utilities of PhSCF2TMS (5) as a "(•)CF2(-)'' building block. The strategy involves fluoride-catalyzed nucleophilic addition of PhSCF2TMS (5) to chiral ketocyclopentenes 6 to provide silylated adducts 9 or alcohol derivatives 10 and 11. Subsequent cascade radical cyclization of the gem-difluoroalkyl radical generated from silylated adducts 9 or alcohols 10 and 11 afforded gem-difluoromethylenated linear triquinanes 16 as an approximate 1:1 mixture of two diastereomers (16A and 16B). Alternatively, a convenient asymmetric synthesis of gem-difluoromethylenated linear triquinanes 16A can be accomplished by oxidation of 16a (R = H) to provide ketotriquinane 17 followed by a highly stereoselective nucleophilic addition to 17 employing DIBAL, NaBH4, and various Grignard reagents.

Synthesis of gem-difluoromethylenated polycyclic cage compounds.

The synthesis of gem-difluoromethylenated polycyclic cage compounds, utilizing PhSCF2SiMe3 as a gem-difluoromethylene building block, is described. The fluoride-catalyzed nucleophilic addition of PhSCF2SiMe3 to both maleic anhydride-cyclopentadiene and maleic anhydride-cyclohexadiene adducts was accomplished with high stereoselectivity to provide the corresponding adducts that were treated with Grignard reagents, followed by acid-catalyzed lactonization to afford the corresponding γ-butyrolactones, each as a single isomer. These γ-butyrolactones underwent intramolecular radical cyclization to give the corresponding tetracyclic cage γ-butyrolactones, which were employed as precursors for the synthesis of gem-difluoromethylenated tetracyclic cage lactols or tetracyclic cage furans, upon treatment with Grignard reagents.

(N-Phenyl-thio-urea-κS)bis-(tri-phenylphosphane-κP)silver(I) nitrate.

In the title salt, [Ag(C7H8N2S)(C18H15P)2]NO3, the coordination geometry about the Ag(I) atom is shallow trigonal pyramidal, with the metal atom displaced by 0.372 (1) Šfrom the plane of the P and S atoms. In the crystal, the cations are linked to the anions by N-H⋯O hydrogen bonds, generating tetra-mers (two cations and two anions), which feature R 2 (2)(8) and R 4 (4)(8) loops. The cations are linked by weak C-H⋯π inter-actions, generating a three-dimensional network.

Crystal structure of [3-(4,5-di-hydro-1,3-thia-zolin-2-yl-κN)-1,3-thia-zolidine-2-thione-κS (2)](1,3-thia-zol-idine-2-thione-κS (2))copper(I) nitrate.

The mononuclear complex salt, [Cu(C3H5NS2)(C6H8N2S3)]NO3, contains a [C9H13CuN3S5](+) cation and an NO3 (-) anion. All of the non-H atoms of the cation lie on a mirror plane, as do the N and one O atom of the nitrate anion, such that the planes of the cation and anion are mutually orthogonal. The cationic complex adopts a slightly distorted trigonal-planar geometry about the Cu(I) cation. In the crystal, layers parallel to (010) are generated by N-H⋯O hydrogen bonds, supported by short S⋯O [3.196 (4) and 3.038 (3) Å] and S⋯S contacts [3.4392 (13) Å]. Adjacent layers are linked by C-H⋯O hydrogen bonds and weak π-π stacking inter-actions [centroid-centroid distance = 4.0045 (10) Å] between the thia-zoline rings, forming a three-dimensional network. This stacking also imposes a close contact, of approximately 3.678 Å, between the Cu(I) cations and the centroids of the six-membered chelate rings of mol-ecules in adjacent layers.

A novel magnetite C18/paracetamol/alginate adsorbent bead for simultaneous extraction of synthetic antioxidants and bisphenol A in water samples.

A novel magnetic composite bead was synthesized using carbon 18, paracetamol and alginate (mC18/Pa/Alg). The bead was applied to simultaneously adsorb butylated hydroxytoluene, butylated hydroxyanisole, and bisphenol A from water samples by magnetic solid-phase extraction (MSPE). The adsorbed analytes were determined by gas chromatography-flame ionization detection. The morphology and composition of the bead were examined by field emission scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffraction analysis, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller surface analysis. The best condition of MSPE included an adsorbent bead made with 0.8% sodium alginate, a 0.3 g adsorbent dose, a sample solution pH of 7, and a desorption time of 20 min in methanol. The proposed method exhibited linearity at concentrations between 0.015 and 1.00 µg mL-1 of analytes. Limits of detection ranged from 6.86 to 9.66 ng mL-1. Recoveries from 80.3 to 100.1% were achieved with interday and intraday precisions (RSDs) of 0.4-4.3%.

A synthesis of γ-trifluoromethyl α,ß-unsaturated γ-butyrolactones using CF(3)SiMe(3) as a trifluoromethylating agent.

A general synthesis of γ-trifluoromethyl α,ß-unsaturated γ-butyrolactones is described. The fluoride-catalyzed nucleophilic addition of a trifluoromethyl (CF3) group generated from (trifluoromethyl)trimethylsilane (CF3SiMe3, Ruppert-Prakash reagent) to a masked maleic anhydride 1 (cyclopentadiene-maleic anhydride adduct) provides the corresponding adducts 2 with high stereoselectivity. The γ-trifluoromethyl α,ß-unsaturated γ-butyrolactones 4 were obtained after treatment of the adducts 2 with Grignard reagents, followed by flash-vacuum pyrolysis.

Chlorido[1H-1,2,4-triazole-5(4H)-thione-κS]bis-(triphenyl-phosphane-κP)copper(I) acetronitrile monosolvate.

In the title solvate, [CuCl(C2H3N3S)(C18H15P)2]·CH3CN, the Cu(I) ion is bonded to two triphenyl-phosphane ligands, one 1H-1,2,4-triazole-5(4H)-thione ligand via its S atom and one chloride ion in a distorted CuP2SCl tetra-hedron. An intra-molecular N-H⋯Cl hydrogen bond, which closes an S(6) ring, helps to establish the conformation of the complex. In the crystal, N-H⋯Cl hydrogen bonds and C-H⋯π inter-actions link the components, generating (110) layers.

catena-Poly[silver(I)-bis-[µ-4-methyl-1H-1,2,4-triazole-3(4H)-thione-κ(2) S:S]-silver(I)-di-µ-thio-cyanato-κ(2) S:N;κ(2) N:S].

In the title one-dimensional coordination polymer, [Ag2(NCS)2(C3H5N3S)2] n , the Ag(I) atom adopts a distorted tetra-hedral AgNS3 geometry. Adjacent Ag(I) atoms in the [001] chain are alternately linked by pairs of bridging 4-methyl-1H-1,2,4-triazole-3(4H)-thione (Hmptrz) ligands (via their S atoms) and double thio-cyanate bridges linking through both S and N atoms (µ-1,3-SCN). An intra-chain N-H⋯N hydrogen bond occurs between the NH group of the triazole ring and the N atom of the thio-cyanate bridging ligand. A (101) sheet structure arises from inter-chain S⋯N short contacts [3.239 (3) Å] involving the thio-cyanate S atom and the triazole-ring N atom and possible very weak π-π stacking [centroid-centroid separation = 4.0762 (18) Å] between the triazole rings.

2-Amino-5-bromo-pyridin-1-ium (2-amino-5-bromo-pyridine-κN (1))trichloridozincate.

The structure of the title salt, (C5H6BrN2)[ZnCl3(C5H5BrN2)], consists of discrete 2-amino-5-bromo-pyridin-1-ium cations and distorted tetra-hedral (2-amino-5-bromo-pyridine)-tri-chlorido-zincate anions. In the crystal, the complex anions and cations are linked via N-H⋯Cl hydrogen bonds into layers parallel to (101). Short Br⋯Cl contacts of 3.4239 (11) and 3.4503 (12) Šare observed, as well as π-π stacking inter-actions between the pyridine and pyridinium rings, with alternating centroid-to-centroid distances of 3.653 (2) and 3.845 (2) Å.

Glabridin.

In the title compound, C20H20O4 {systematic name: 4-[(3R)-8,8-dimethyl-3,4-dihydro-2H-pyrano[2,3-f]chromen-3-yl]benz-ene-1,3-diol}, the hydro-pyran ring linked to the pendant benzene ring adopts an envelope conformation, with the methyne C atom forming the flap. In the crystal, the -OH group at the 3-position of the benzene ring forms an O-H⋯O hydrogen bond to a chromene O-atom acceptor, whereas the -OH group at the 1-position forms an O-H⋯π inter-action with a neighboring benzene ring. The O-H⋯O hydrogen bonds form [001] chains and the O-H⋯π bonds cross-link the chains into (101) sheets. The absolute structure was assumed to be the same as that deduced from previous studies for the natural product.

catena-Poly[copper(I)-di-µ-bromido-copper(I)-bis-[µ-4-methyl-1H-1,2,4-triazole-5(4H)-thione-κ(2)S:S]].

In the title coordination polymer, [CuBr(C(3)H(5)N(3)S)](n), the Cu(I) atom adopts a tetra-hdral CuS(2)Br(2) coordination geometry arising from two S-bonded 4-methyl-1H-1,2,4-triazole-3(4H)-thione ligands and two bromide ions. Both the S and Br atoms act as bridging ligands, connecting pairs of Cu(I) atoms and generating chains propagating in [100]. Inter-chain N-H⋯N hydrogen bonds generate layers in the ac plane. Weak intra-chain N-H⋯Br inter-actions also occur.

2-{2-[4-(Dimethyl-amino)-phen-yl]diazen-1-ium-1-yl}pyridinium tetra-chlorido-zincate.

The title compound, (C(13)H(16)N(4))[ZnCl(4)], consists of a tetra-hedral [ZnCl(4)](2-) anion and a 2-{2-[4-(dimethyl-amino)-phen-yl]diazen-1-ium-1-yl}pyridinium dication. The pyridinium-N atom is syn to the azo bond which allows for the formation of an intramolecular N-H⋯N hydrogen bond. In the crystal, the cation and anion are held together by N-H⋯Cl hydrogen-bond inter-actions involving the pyridinium and diazen-1-ium N atoms. π-π stacking inter-actions occur between the pyridine and benzene rings of adjacent cations [centroid-centroid distances = 3.6270 (18) and 3.8685 (18) Å]; the stacks are parallel to the a axis.

Iodido[1-(propan-2-yl-idene)thio-semi-carbazide-κS]bis-(triphenyl-phosphane-κP)copper(I).

In the mononuclear title complex, [CuI(C(4)H(9)N(3)S)(C(18)H(15)P)(2)], the Cu(I) ion displays a distorted tetra-hedral coordination geometry involving two P atoms of two triphenyl-phosphane mol-ecules, one S atom of a 1-(propan-2-yl-idene)thio-semicarbazide mol-ecule and one iodide ion. In the crystal, C-H⋯π inter-actions [C-H⋯centroid distances = 3.443 (3) and 3.788 (3) Å] and N-H⋯S hydrogen bonds form layers parallel to (100). An intra-molecular N-H⋯I hydrogen bond is also observed.

Bis[5-chloro-2-(phenyl-diazenyl-κN(2))pyridine-κN]bis-(thio-cyanato-κN)iron(II).

In the title complex, [Fe(NCS)(2)(C(11)H(8)ClN(3))(2)], the Fe(II) atom is coordinated by two N atoms from the thio-cyanate ligands and four N atoms from two chelating 5-chloro-2-(phenyl-diazen-yl)pyridine ligands, generating a fairly regular FeN(6) octa-hedral coordination geometry. The thio-cyanate ions are in a cis disposition and the pyridine N atoms are in a trans orientation. In the crystal, a short inter-molecular Cl⋯S contact [3.366 (3) Å] is observed.

Syntheses, crystal structures and Hirshfeld surface analyses of bis-(2-mercaptobenzimidazole)-bromo- and iodo-copper(I) complexes.

The title complexes, bromidobis(2,3-dihydro-1H-1,3-benzodiazole-2-thi-one)copper(I), [CuBr(C7H6N2S)2] (1), and bis(2,3-dihydro-1H-1,3-benzodiazole-2-thione)iodidocopper(I) acetone monosolvate, [CuI(C7H6N2S)2]·CH3COCH3 (2), were prepared by the reaction of copper(I) bromide/iodide with 2-mercaptobenzimidazole. Both complexes have mononuclear structures with the copper atom coordinated by two 2-mercaptobenzimidazole mol-ecules via their S atoms and one halide atom in an approximate trigonal-planar arrangement. In their extended structures, N-H⋯S hydrogen bonds and π-π contacts are found in both complexes; as a result of the acetone solvent mol-ecule in (2), N-H⋯O contacts are also observed. Hirshfeld surface analyses were carried out to aid in the visualization of these inter-actions, which showed that H⋯H contacts contribute 34.6% for (1) and 34.1% for (2) to the overall surface, followed by contributions from H⋯S/S⋯H, H⋯C/C⋯H and C⋯C contacts, respectively. As expected, H⋯O/O⋯H contacts are observed only in (2). The IR and 1H and 13C NMR spectra of (1) and (2) are described.