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The tetraene 7,7‐dimethoxy‐2,3,5,6‐tetramethylenebicyclo[2.2.1]heptane is a key compound for the preparation of a large variety of acenes protected by a carbonyl bridge. We report herein a medium scale preparation in seven steps of this valuable starting material. Diels–Alder addition between 6,6‐dimethtyl fulvene and maleic anhydride, followed by carboxylation, ozonolysis of the double bond, reduction of the four ester groups, then chlorination of the alcohol groups and dehydrochlorination give the target compound in 17 % overall yield. [ABSTRACT FROM AUTHOR]

Selective reduction of 1,5-diazacyclooctatetraenes with potassium or a Co(i) complex was achieved to provide the first structurally well-defined aromatic 1,5-diazacyclooctatetraenyl dianion or a novel dinuclear Co(ii) complex bridged by a bipyrrolinyl dianion, respectively. [ABSTRACT FROM AUTHOR]

Abstract Twenty-four diterpenoids of abietane family, including thirteen undescribed compounds and eleven known ones, were isolated from the leaves of Leucosceptrum canum. Their structures were elucidated by comprehensive spectroscopic analyses (including 1D and 2D-NMR and HRMS), and in the case of 15-hydroxy-abieta-8,11,13-trien-3-one by single-crystal X-ray diffraction. Their frameworks are highly diversified, involving normal abietane, 9,10-epoxy-9,10- seco -abietane, 18(4 → 3)- abeo -abietane, 3,4- seco -18(4 → 3)- abeo -abietane, and 16- nor -abietane. Selected compounds were evaluated for their cytotoxic activity against three human tumor cell lines, NCI-H1975, HepG2 and MCF-7. Among them, 3β-hydroxy-abieta-8,13-diene, 3β-hydroxy-abieta-8,11,13,15-tetraene, and 3β-hydroxy-9,10-epoxy-9,10- seco -abieta-8,11,13-triene exhibited moderate cytotoxicity against all three cell lines with IC 50 values ranging from 8.11 to 50.73 μM, while 3α-hydroxy-abieta-8,11,13,15-tetraene, 3β-hydroxy-abieta-8,11,13,15-tetraen-7-one, and 15-hydroxy-18(4 → 3)- abeo -abieta-3,8,11,13-tetraene were selectively active with IC 50 values ranging from 28.80 to 71.29 μM. Graphical abstract Thirteen undescribed abietane family diterpenoids along with eleven known ones were isolated from the aerial parts of Leucosceptrum canum. Six of them showed moderate cytotoxic activity. Image 1 Highlights • Twenty-four including 13 undescribed abietanoids were isolated from Leucosceptrum canum. • Their skeletons included normal, seco- , abeo -, seco - abeo- and nor -abietanes. • Six abietanoids showed moderate cytotoxicity against three tumor cell lines. • This is the first report of abietane family diterpenoids from Leucosceptrum canum. [ABSTRACT FROM AUTHOR]

A synthetic method to prepare bicyclo[6.3.0]undeca‐2,4,9,trienyl esters efficiently from gold(I)‐catalyzed Rautenstrauch rearrangement/1,5‐hydride shift/8‐endo‐dig cyclization of 1‐ene‐4,10‐diynyl esters is described. The suggested double cycloisomerization mechanism delineates the first example of an unactivated all‐carbon tethered 1,7‐enyne, either preformed or formed in situ, which undergoes an 8‐endo‐dig cyclization pathway to give a cyclooctane motif. It also offers an extremely rare synthetic method in organic chemistry that can sequentially assemble both ring components of the bicyclic motif from an acyclic precursor in one step. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • First total synthesis of keto-tetraene 15-oxo-Lipoxin A4 has been achieved. • Synthetic approach: iterative palladium-catalyzed coupling using a MIDA boronate. • Dess-Martin oxidation of 15-position hydroxyl to electrophilic keto. • Key steps: Sonogashira, Suzuki couplings; Zinc(Copper/Silver) reduction of trien-yne. Abstract 15-oxo-Lipoxin A 4 (15-oxo-LXA 4) has been identified as a natural metabolite of the fatty acid signaling mediator Lipoxin A 4. Herein, we report a total synthesis of the methyl ester of 15-oxo-LXA 4 to be used in investigations of potential electrophilic bioactivity of this metabolite. The methyl ester of 15-oxo-LXA 4 was synthesized in a convergent 15 step (9 steps longest linear) sequence starting from 1-octyn-3-ol and 2-deoxy- d -ribose with Sonogashira and Suzuki cross-couplings of a MIDA boronate as key steps. [ABSTRACT FROM AUTHOR]

Bicyclo[4.3.1]deca-2,4,8-triene-7,10-diols were synthesized in 76–85% yields by oxidative skeletal isomerization of the substituted bicyclo[4.2.2]deca-2,4,7,9-tetraenes of various structures on treatment with m -chloroperbenzoic acid. The structures of the obtained bicyclic unsaturated diols were reliably proven by modern spectral methods and X-ray diffraction. A high antitumor activity in vitro was found for bicyclo[4.3.1]deca-2,4,8-triene-7,10-diols against the Jurkat, K562, U937 and HL-60 tumor cell lines. [ABSTRACT FROM AUTHOR]

Fusarithioamide B ( 6 ), a new aminobenzamide derivative with unprecedented carbon skeleton and five known metabolites: stigmast-4-ene-3-one ( 1 ), stigmasta-4,6,8(14),22-tetraen-3-one ( 2 ), p -hydroxyacetophenone ( 3 ), tyrosol ( 4 ), and fusarithioamide A ( 5 ) were separated from Fusarium chlamydosporium EtOAc extract isolated from Anvillea garcinii (Burm.f.) DC. leaves (Asteraceae). The structure elucidation and complete assignment of the isolated metabolites were performed mainly by the aid of various NMR and MS data. Fusarithioamide B ( 6 ) has been assessed for antibacterial and antifungal activities towards various microbial strains by disc diffusion assay. It exhibited selective antifungal activity towards C. albicans (MIC 1.9 µg/ml and IZD 14.5 mm), comparing to clotrimazole (MIC 2.8 µg/ml and IZD 17.9 mm). Also, it possessed high antibacterial potential towards E . coli , B. cereus , and S . aureus compared to ciprofloxacin. Furthermore, 6 was tested for the in vitro cytotoxic effect against KB, HCT-116, BT-549, MCF-7, SKOV-3, and SK-MEL cell lines. It had selective and potent effect towards BT-549, MCF-7, SKOV-3, and HCT-116 cell lines with IC 50 s 0.09, 0.21, 1.23, and 0.59 μM, respectively compared to doxorubicin (IC 50 s 0.046, 0.05, 0.321, and 0.24 μM, respectively). Fusarithioamide B may provide a lead molecule for future developing of antitumor and antimicrobial agents. [ABSTRACT FROM AUTHOR]

The Ru(0)-catalyzed straightforward synthesis of conjugated tetraenes has been achieved in up to 85% yield by coupling of 2 equiv of internal alkynes with 1,3-butadiene at room temperature. The stoichiometric reaction of [Ru(η4-cisoid-1,3-butadiene)(η4-1,5-COD)(NCMe)] with 2 equiv of 3-hexyne produces a tetraene complex of Ru(0), [Ru{3-6-η4-(3E,5E,7E,9E)-4,9-diethyldodeca-3,5,7,9-tetraene}(η4-1,5-COD)(NCMe)], in 98% yield, which releases the conjugated tetraene ligand in 92% yield by exposure to 1,3-butadiene. [ABSTRACT FROM AUTHOR]

Without employing high dilution conditions, the fourfold 2+2 Perkin reaction of 1,6-pyrenylene-diglyoxylic acid with its reduction product 1,6-pyrenylene-diacetic acid yields the corresponding tetrameric conjugated macrocycle in 25% overall yield after in-situ esterification. The macrocycle adopts a square fourfold symmetry in the crystal, with near-vertical pyrene walls that alternatingly tilt upwards and downwards. [ABSTRACT FROM AUTHOR]

In search of more effective chemotherapeutics for the treatment of castration-resistant prostate cancer and inspired by curcumin analogues, twenty five (1 E ,3 E ,6 E ,8 E )-1,9-diarylnona-1,3,6,8-tetraen-5-ones bearing two identical terminal heteroaromatic rings have been successfully synthesized through Wittig reaction followed by Horner–Wadsworth–Emmons reaction. Twenty-three of them are new compounds. The WST-1 cell proliferation assay was employed to assess their anti-proliferative effects toward both androgen-sensitive and androgen-insensitive human prostate cancer cell lines. Eighteen out of twenty-five synthesized compounds possess significantly improved potency as compared with curcumin. The optimal compound, 78 , is 14- to 23-fold more potent than curcumin in inhibiting prostate cancer cell proliferation. It can be concluded from our data that 1,9-diarylnona-1,3,6,8-tetraen-5-one can serve as a new potential scaffold for the development of anti-prostate cancer agents and that pyridine-4-yls and quinolin-4-yl act as optimal heteroaromatic rings for the enhanced potency of this scaffold. Two of the most potent compounds, 68 and 75 , effectively suppress PC-3 cell proliferation by activating cell apoptosis and by arresting cell cycle in the G 0 /G 1 phase. [ABSTRACT FROM AUTHOR]

The recent vibrational analysis of the experimental IR spectra of the non-planar gauche,Trans,trans,Trans,gauche possible rotational isomers of octa-1,3,5,7-tetraene (C i and C 2 ) is reconsidered. Calculations of the vibrational frequencies of the non-planar C i and C 2 conformers of C 8 H 10 and C 8 D 10 are performed. Some of the calculated vibrational frequencies of the non-planar C i conformer are reassigned. Comparison of the IR experimental frequencies with the calculated frequencies for the two non-planar conformers suggests that all experimental bands belong to the non-planar C 2 conformer. [ABSTRACT FROM AUTHOR]

Lucensomycin, tetraene macrolide antibiotic, has been chemically modified with dialkyl(diaryl) phosphites under conditions of the Todd-Atherton reaction. The reaction has yielded the corresponding dialkyl-(diaryl) amidophosphate derivatives of the antibiotic. Physico-chemical properties of the prepared derivatives as well as their toxicity and antifungal activity towards a series of pathogenic Candida yeast-like fungi have been studied. The automated decision-making information system for selection of highly efficient antibiotics has been described. [ABSTRACT FROM AUTHOR]

The equilibrium geometries of heptatriynylidene ( 1 ), cyclohepta-1,2,3,4-tetraen-6-yne ( 2 ), and heptahexaenylidene ( 3 ) have been theoretically investigated at various level of theories. The methods employed are Møller–Plesset perturbation level of theory until second-order, coupled-cluster singles and doubles (CCSD), and CCSD with perturbative triple excitations [CCSD(T)]. Correlation consistent polarized valence double and triple zeta (cc-pVXZ; X = D and T) basis sets are used in all calculations, which are compatible with the frozen-core approximation entreated in this study. The relative energies of the ground triplet electronic state ( X ∼ 3 Σ g - ) of 1 – the most stable isomer of C 7 H 2 – to the ground singlet electronic states of 2 ( X ∼ 1 A 1 ) and 3 ( X ∼ 1 A 1 ) have also been estimated at different levels. With zero-point vibrational energy corrections, 2 and 3 are found to lie ∼12.27 and ∼20.62 kcal mol −1 , respectively, above 1 at the highest level of theory (CCSD(T)/cc-pVTZ). While 1 and 3 are observed in the laboratory, 2 is a hypothetical molecule hitherto. Since the optimal geometry of 2 suggests the presence of biradical character, the singlet–triplet ( X ∼ 1 A 1 – 3 B 1 ) energy gap for isomer 2 was also calculated at various levels. The ab initio data presented here may be useful for the laboratory detection of 2 and astronomical detection of 2 and 3 . [ABSTRACT FROM AUTHOR]

M06-2X/6-31+G(d,p) computations are reported for the 8π-6π electrocyclization cascades of 1,3,5,7-tetraenes. The rate-determining step for these cascades is typically the second (6π) ring closure. According to experiment and theory, un- and monosubstituted tetraenes readily undergo 8π electrocyclic ring closure to form 1,3,5-cyclooctatrienes; however, the 6π electrocyclizations of these cyclooctatriene intermediates are slow and reversible, and mixtures of monocyclic and bicyclic products are formed. Computations indicate that di- and trisubstituted tetraenes undergo facile but less exergonic 8π electrocyclization due to a steric clash that destabilizes the 1,3,5-cyclooctatriene intermediates. Relief of this steric clash ensures the subsequent 6π ring closures of these intermediates are both kinetically facile and thermodynamically favorable, and only the bicyclic products are observed for the cascade reactions of naturally occurring tri- and tetrasubstituted tetraenes (in agreement with computations). The 6π electrocyclization step of these cascade electrocyclizations is also potentially diastereoselective, and di- and trisubstituted tetraenes often undergo cascade reactions with high diastereoselectivities. The exo mode of ring closure is favored for these 6π electrocyclizations due to a steric interaction that destabilizes the endo transition state. Thus, theory explains both the recalcitrance of the unsubstituted 1,3,5,7-octatetraene and 1-substituted tetraenes toward formation of the bicyclo[4.2.0]octa-2,4-diene products, as well as the ease and the stereoselectivity with which terminal di- and trisubstituted tetraenes are known to react biosynthetically. [ABSTRACT FROM AUTHOR]

To investigate the relationship between structure and biological activity of analogues of steroid estrogens we have developed the synthesis of 7α-methyl-6-oxa-estra-1,3,5(10),8(9)-tetraenes with cis- and trans-junction of C and D rings. We found that such compounds have stronger osteoprotective, cholesterol-lowering and antioxidant properties in comparison with uterotrophic activity; that is the advantage in comparison with clinically used 17α-ethynylestradiol. [ABSTRACT FROM AUTHOR]

The cobalt-catalysed 1,4-hydrovinylation of an aryl-substituted 1,3,5-hexatriene was investigated on a large scale for the synthesis of a double-skipped 1,4,7-triene product. The reaction proceeds via a regioselective C-H activation of the alkene and the exclusive formation of the 4Z-double bond. The cobalt-catalysed 1,4-hexatrienylation of a butadiene derivative led exclusively to the desired all-E tetraene product. Finally, the cobalt-catalysed Diels-Alder reaction with trimethylsilyl-substituted alkynes was investigated. The cycloadducts were generated with excellent chemo- and regioselectivity to give the corresponding stilbene derivative. [ABSTRACT FROM AUTHOR]

A strategy for the stereoselective synthesis of (2 Z,4 Z,6 Z,8 Z)-decatetraene diketone by the one-step metal reduction of pyrylium salts is described. Reduction of α-active pyrylium salts (at least one H at the α-C positon) leads to only linear decatetraene diketone derivatives, whereas reduction of α-non-active pyrylium salts (no H at the α-C position) generates two unexpected structures and one linear decatetraene diketone. The reaction conditions were optimized, and a reaction mechanism was proposed. Single-crystal structures of decatetraene diketone derivatives demonstrate the twisted configuration of the backbones and the all-( Z) geometry of the double bonds. In addition, the thermal, optical, and electrochemical properties of these compounds were studied in detail. [ABSTRACT FROM AUTHOR]

The formal [2 + 2] cycloaddition--retroelectrocyclization reaction was employed as the key transformation to obtain donor-substituted, π-conjugated polycyanohexa-1,3,5-trienes (TCHTs and PCHTs) and polycyanoocta-1,3,5,7-tetraenes from donor-substituted tetracyanobuta-1,3-dienes (TCBDs) and electron-rich alkynes. These push--pull-substituted oligoene chromophores were also accessed in good yield from tetracyanoethylene and donor-substituted alkynes by using a one-pot protocol. All bis-(N,N-dialkylanilino) donor-substituted push-pull trienes and tetraenes showed better electron-accepting potency and lower HOMO-LUMO gaps than the corresponding TCBDs, as evidenced by optical and electrochemical studies. [ABSTRACT FROM AUTHOR]

3-Aroyl-1 H-pyrrolo[2,1- c][1,4]benzoxazine-1,2,4-triones reacted with alkyl vinyl ethers according to the [4 + 2]-cycloaddition pattern with formation of substituted (1 S*,16 R*)- and (1 R*,16 R*)-16-alkoxy-14-aryl-3,15-dioxa-10-azatetracyclo[8.7.0.0.0]heptadeca-4,6,8,13-tetraene-2,11,12-triones. The structure of (1 S*,16 R*)-7-chloro-16-ethoxy-14-phenyl-3,15-dioxa-10-azatetracyclo[8.7.0.0.0]heptadeca-4,6,8,13-tetraene-2,11,12-trione was determined by X-ray analysis. A new synthetic approach was developed to heteroanalogs of 13(14→8)-abeo steroids, substituted 3,15-dioxa-10-azatetracyclo[8.7.0.0.0]heptadecanes. [ABSTRACT FROM AUTHOR]

The identity of the major product of Ru-catalysed alkene metathesis of two polyene substrates has been determined using density functional theory (DFT) NMR prediction, a 1H-1H Total Correlated Spectroscopy (TOCSY) NMR experiment and ultimately by single-crystal X-ray crystallography. The substrates were designed as those that would potentially allow expedient access to the trans-decalin skeleton of the natural product (−)-euonyminol, but the product was found to be a bis-cyclopentenyl-β-cyanohydrin [1-(1-hydroxycyclopent-3-en-1-yl)cyclopent-3-ene-1-carbonitrile, C11H13NO] rather than the trans-2,3,6,7-dehydrodecalin-β-cyanohydrin. [ABSTRACT FROM AUTHOR]

The promethea moth Callosamia promethea is one of three species of silkmoths from the genus Callosamia that occur in North America. Cross attraction of males to heterospecific calling females has been observed in the field, and hybrid progeny have been produced by pairing heterospecifics in captivity. These observations suggest that all three species share or have considerable overlap in the sex attractant pheromones produced by females, so that other prezygotic isolating mechanisms, such as diel differences in reproductive activity, limit hybridization in the field. Coupled gas chromatography-electroantennogram detection and gas chromatography- mass-spectrometry analyses of extracts of volatiles collected from female promethea moths supported the identification of (4 E,6 E,11 Z,13 Z)-hexadeca-4,6,11,13-tetraenal [(4 E,6 E,11 Z,13 Z)-16:Ald] as the compound in extracts that elicited the largest responses from antennae of males. The identification was confirmed by non-selective synthesis of several isomers as analytical standards, and stereoselective synthesis of (4 E,6 E,11 Z,13 Z)-16:Ald for testing in field trials. Male moths were strongly attracted to synthetic (4 E,6 E,11 Z,13 Z)-16:Ald, suggesting that this compound is the major and possibly the only component of the sex pheromone of these large saturniid moths. Based on the cross-attraction of heterospecifics, it is likely that this is also a major pheromone component of the other two North American Callosamia species as well. [ABSTRACT FROM AUTHOR]

trans-11,12-Epoxy-(6 Z,9 Z)-6,9-henicosadiene (posticlure) has been identified from a pheromone gland of the lymantriid species, Orgyia postica. Since the diversity of Lepidoptera suggests that some species utilize the structure-related epoxy compound as a sex pheromone component, epoxydienes and epoxytrienes derived from (6 Z,9 Z,11 E)-6,9,11-trienes and (3 Z,6 Z,9 Z,11 E)-3,6,9,11-tetraenes with a C-C chain were systematically synthesized and the chemical data were accumulated in order to contribute to a new pheromone research. Peracid oxidation of each triene and each tetraene produced, respectively, a mixture of three epoxydienes ( cis-6,7-epoxy-9,11-diene; cis-9,10-epoxy-6,11-diene; and trans-11,12-epoxy-6,9-diene) and four epoxytrienes ( cis-3,4-epoxy-6,9,11-triene; cis-6,7-epoxy-3,9,11-triene; cis-9,10-epoxy-3,6,11-triene; and trans-11,12-epoxy-3,6,9-triene). While the 9,10-epoxy compounds were unstable and, interestingly, converted into 9-ketone derivatives after chromatography over SiO, each positional isomer was isolated by HPLC equipped with an ODS column, and the chemical structure was determined by NMR analysis. On the GC-MS analysis with a DB-23 column, the positional isomers were also eluted separately and characteristic mass spectra were proposed. By comparing the spectral data of the epoxy compounds with a different carbon chain, diagnostic fragment ions reflecting the chemical structure were determined as follows: m/z 79, 109, 113, and M-114 for the 6,7-epoxydienes; m/z 69, 97, 111, 139, and M-111 for the 9,10-epoxydienes; m/z 57, 79, 109, 136, M-151, and M-111 for the 11,12-epoxydienes; m/z 79, 91, 105, and 119 for the 3,4-epoxytrienes; m/z 79, 124, M-124, M-96, and M-69 for the 6,7-epoxytrienes; m/z 79, 95, 109, 137, and M-108 for the 9,10-epoxytrienes; and m/z 79, 134, M-149, M-109, and M-95 for the 11,12-epoxytrienes. [ABSTRACT FROM AUTHOR]

The marine fungus Paecilomyces sp., derived from the marine sponge collected along Tinggi Island, Malaysia, was cultivated and incubated for 7 days at 30°C. The liquid cultures were then extracted, and the crude extract was investigated for its antimicrobial activity. Purification of the crude extract resulted in the isolation of the new (3 R*,5 E,7 E,9 R*,11 E,13 Z)-1-((3′a S*,6′a R*)-2′-amino-5′-oxo-3′a,5′,6′,6′a-tetrahydrofuro [3′,2′-b]furan-3-yl)-3,7,9,11-tetramethylheptadeca-5,7,11,13-tetraene-1,2-dione ( 1) and four known metabolites, stigmasterol ( 2), cholesteryl linoleate ( 3), linoleic acid ( 4), and 2,5-furandimethanol ( 5). The structures of the components were elucidated by spectroscopic methods. The antimicrobial activities of all the isolated compounds were evaluated against a panel of bacteria and fungi. [ABSTRACT FROM AUTHOR]

The synthesis of Pd nanoparticles (Pd-NPs) supported on multi-walled carbon nanotubes (MWCNTs) and the cataytic performance of the resulting material (Pd-NPs/MWCNTs) in hydrogenation reactions are presented. Facile preparation approaches based on the decomposition of Pd precursors in the presence of MWCNTs lead to homogeneous dispersions of supported Pd-NPs with an average size of 4 nm and Pd loads of about 12%. The catalytic performance of this material was evaluated in hydrogenation reactions of α,β-unsaturated ketones, alkenes, cyclic di-, tri- and tetraenes, aromatic compounds, terpenes and terpenoids, resulting in very high activity offering short reaction times, high conversion rates, notable selectivity, and acceptable recyclability under mild conditions. [ABSTRACT FROM AUTHOR]

Two cDNAs encoding putative type 1 acyl-CoA: diacylglycerol acyltransferases (DGAT1, EC 2.3.1.20), were cloned from Tetraena mongolica, an extreme xerophyte with high oil content in the stems. The 1 488-bp and 1 485-bp of the open reading frame (ORF) of the two cDNAs, designated as TmDGAT1a and TmDGAT1b, were both predicted to encode proteins of 495 and 494 amino acids, respectively. Southern blot analysis revealed that TmDGAT1a and TmDGAT1b both had low copy numbers in the T. mongolica genome. In addition to ubiquitous expression with different intensity in different tissues, including stems, leaves and roots, TmDGAT1a and TmDGAT1b, were found to be strongly induced by high salinity, drought and osmotic stress, resulting in a remarkable increase of triacylglycerol (TAG) accumulation in T. mongolica plantlets. TmDGAT1a and TmDGAT1b activities were confirmed in the yeast H1246 quadruple mutant ( DGA1, LRO1, ARE1, ARE2) by restoring DGAT activity of the mutant host to produce TAG. Overexpression of TmDGAT1a and TmDGAT1b in soybean hairy roots as well as in T. mongolica calli both resulted in an increase in oil content (ranging from 37% to 108%), accompanied by altered fatty acid profiles. [ABSTRACT FROM AUTHOR]

Abstract: The roots of the medicinal ornamental plant Clerodendrum trichotomum yielded a series of rearranged abietane diterpenoids, including three 17(15→16)-abeo-abietane (1–3) and three 17(15→16),18(4→3)-diabeo-abietane (4–6) derivatives. Their structures were elucidated by means of spectroscopic methods. The absolute configuration of (10R,16R)-12,16-epoxy-11,14,17-trihydroxy-6-methoxy-17(15→16)-abieta-5,8,11,13-tetraene-7-one (1) was deduced by a combination of single crystal X-ray diffraction analysis and the observed Cotton effects in its circular dichroism (CD) spectrum. All isolates were tested for their cytotoxicities against five human cancer cell lines (BGC-823, Huh-7, KB, KE-97, and Jurkat). Among them, compounds 4, 6, 9, 10, 12, and 14, each possessing a common 17(15→16),18(4→3)-diabeo-abietane framework, were found to have remarkable cytotoxic effects with IC50 values ranging from 0.83 to 50.99μM. [Copyright &y& Elsevier]

Diorganotin(IV) and triorganotin(IV) derivatives of the types R2SnA (R= n-Bu and n-octyl) and (R3Sn)2A (R= n-Bu), where A is the anion of albendazole {methyl[(5-propylsulfanyl-3 H-benzoimidazol-2-yl) amino]formate}, ofloxacin {( RS)-7-fluoro-2-methyl-6-(4-methylpiperazin-1-yl)-10-oxo-4-oxa-1-azatricyclo[7.3.1.05,13] trideca-5(13),6,8,11-tetraene-11-carboxylicacid} and 3-carboxypropyldisulfide, have been synthesized. The complexes 1- 9 obtained were characterized by elemental analysis as well as infrared (Fourier transform infrared), nuclear magnetic resonance (1H, 13C and 119Sn NMR) and ultraviolet spectroscopy. On the basis of these spectroscopic studies it was proposed that diorganotin complexes of 3-carboxypropyldisulfide having 1:1 stoichiometry and complexes of albendazole and ofloxacin having 1:2 stoichiometry show tetrahedral geometry around the tin atom with monodentate behavior of the carboxylate group in ofloxacin and 3-carboxypropyldisulfide. Triorganotin complexes of 3-carboxypropyldisulfide having 1:1 stoichiometry and complexes of ofloxacin and albendazole having 1:2 stoichiometry show trigonal bipyramidal geometry. The ligand molecule is bound to the Sn atom through carboxyl oxygen atoms in ofloxacin and 3-carboxypropyldisulfide, and to the nitrogen atom in albendazole. The biological activity of the synthesized complexes 4, 5 and 6 has been screened against Candida albicans. [ABSTRACT FROM AUTHOR]

Abstract: To improve the therapeutic effect of ergosta-4,6,8(14),22-tetraen-3-one (ergone), a folate–decorated ergone–bovine serum albumin nanoparticles (abbreviated FA–ergone–BSANPs) was prepared. The properties were extensively studied by Zetasizer Nano Particle Size Analyzer and TEM, which indicated the prepared nanoparticles were spherical in shape and uniform in size with a zeta potential of −23.8mV. The drug-loading capacity also has been determined with drug loading content of 2.73% and encapsulation efficiency of 61.8%. In vitro release studies proved the much slow drug release from the nanoparticles during circulating in the blood stream and the increase of drug release at the target sites. The FA–ergone–BSANPs showed enhanced cellular uptake, increased targeting capacity, and increased cytotoxicity against KB cells over-expressing folate receptor (FR), which indicated that its potent cell-killing activity is specific for cells that express the FR. In vivo experiment also confirmed that FA–ergone–BSANPs represent a FR-targeted chemotherapeutic that can produce potent activity against FR-positive tumors. In conclusion, this report has a great significance in pharmacology and clinical medicine as well as methodology. Further detailed dose-optimization studies will be required for better understanding in vivo pharmacokinetic and bio-distribution behaviors. [Copyright &y& Elsevier]

The early stages of the [3+2]-photocycloaddition of 1,4-dicyano-6-methylnaphthalene ( 6) with styrene ( 7) were investigated by UV-visible absorption and H NMR spectroscopy. An intermediate species was detected and characterized as 8-methyl-2-phenyl-1,2,2a,8-tetrahydroacenaphthylene-2a,5-dicarbonitrile ( 9). Computational studies explained the regioselective [3+2]-photocycloaddition at the 4,5-position of 6 to form zwitterion 8, and subsequent thermal transformation to form 9. [ABSTRACT FROM AUTHOR]

An efficient and general method is reported to prepare a diverse series of 5,5-spirocyclic and 1,5-, 4,5-, and 3,4-fused bicydic imidazolidinone derivatives based on selective alleviation and ring closing metathesis (RCM) by exploiting the four possible points of diversity in the hydantoin ring. Hydantoins containing trienes and tetraenes undergo selective RCM and cross metathesis to afford functionalized spirohydantoins. A tandem metathesis sequence involving ring closing--ring opening--ring closing and cross metathesis (RC-RO--RC--CM) occurred with a hydantoin triene to give a bicyclic hydantoin dimer in high yield. The fused bicylic dimer could participate in cross metathesis to produce a functionalized fused hydantoin derivative. The methodology establishes novel routes to unnatural amino acids, proline homologues, and cyclic vicinal diamines. [ABSTRACT FROM AUTHOR]

We analyze the behavior of the energy profile of the ring-closure process for the transformation of (3 Z,5 Z)-octa-1,3,5,7-tetraene 5 to (1 Z,3 Z,5 Z)-cycloocta-1,3,5-triene 6 through a combination of electron localization function (ELF) and catastrophe theory (CT). From this analysis, concepts such as bond breaking/forming processes, formation/annihilation of lone pairs, and other electron pair rearrangements arise naturally through the reaction progress simply in terms of the different ways of pairing up the electrons. A relationship between the topology and the nature of the bond breaking/forming processes along this rearrangement is reported. The different domains of structural stability of the ELF occurring along the intrinsic reaction path have been identified. The reaction mechanism consists of six steps separated by fold and cusp catastrophes. The transition structure is observed in the third step, d(C1C8) = 2.342 Å, where all bonds have topological signature of single bonds (CC). The 'new' C1C8 single bond is not formed in transition state and respective catastrophe of the ELF field (cusp) is localized in the last step, d(C1C8) ≈ 1.97 Å, where the two monosynaptic nonbonding basins V(C1) and V(C8) are joined into single disynaptic bonding basin V(C1,C8). The V(C1,C8) basin corresponds to classical picture of the C1C8 bond in the Lewis formula. In cycloocta-1,3,5-triene 6 the single C1C8 bond is characterized by relatively small basin population 1.72 e, which is much smaller than other single bonds with 2.03 and 2.26 e. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011 [ABSTRACT FROM AUTHOR]

A sequence of two Diels-Alder reactions is observed for the reaction of bis-diene (E)-3-[2-(furan-2-yl)vinyl]-5,5-dimethylcyclohex-2-en-1-one with two equivalents of N-phenylmaleimide. This study shows that the electron-deficient furanyl site, which is primarily 'inactive' towards a [4 + 2] reaction, easily undergoes cycloaddition with the second equivalent of N-phenylmaleimide to produce the final bisadduct. This is because the first Diels-Alder reaction between N-phenylmaleimide and the more reactive cyclohex-2-en-1-one site of the diene converts the 2-furanyl ring to a more electron-rich component, since the electron-withdrawing double bond attached to the furan ring changes to an electron-releasing alkyl group after the first cycloaddition. Consequently, the resulting furanyl diene is then able to undergo the second cycloaddition. [ABSTRACT FROM AUTHOR]

Abstract: Acyclic conjugated (E,Z,E,E)-tetraenes, upon thermolysis, undergo a domino pericyclic process involving 6π electrocyclisation of the (E,Z,E)-triene moiety to give the corresponding cis-disubstituted 5-vinyl-1,3-cyclohexadienes, followed by an intramolecular Diels–Alder reaction with the vinyl side chain to give tricyclo[3.2.1.02,7]oct-3-enes. [Copyright &y& Elsevier]

The catalytic autoxidation of hydrogensulfite (hydrogentrioxosulfate(1-)) in the presence of Co(tim)(H 2 O) 2 2+ (tim=2,3,9,10-tetramethyl-1,4,8,11-tetraazacyclotetradeca-1,3,8,10-tetraene) was studied. Dioxygen reacts with excess sulfite in the presence of Co(tim)(H 2 O) 2 2+ in a complex process (a minimum of five kinetic steps can be identified) to produce Co(tim)(SO 3 ) x (3 m 2 x )+ ( x =1 or 2) ( u max at 350 nm) and sulfate. Seventy turnovers over 4 h were attained in a system where dioxygen and sulfite were supplied constantly. The Co(III) product formed reacts only slowly with dioxygen to produce sulfate. A mechanistic analysis of the results implies the involvement of a Co(tim)-dioxygen adduct, stabilized by an axial sulfite ligand. [ABSTRACT FROM AUTHOR]

Colonies of the soft coral Lobophytum pauciflorum (Ehrenberg, 1834) (Coelenterata: Octocorallia: Alcyonacea: Alcyoniidae), some of which were heavily overgrown by the algae Ceranium flaccidum (Kuetzing) Ardissone and Enteromorpha sp., and other minor epizoites, were collected at Taylor Reef (17°50′S; 146°35′E) in the Great Barrier Reef. Overgrown colonies contained the diterpene 2-epi-sarcophytoxide as the major secondary metabolite, while conspecific colonies with clean polyparies contained two diterpenes in approximately equal amounts: 14-hydroxycembra-1,3,7,11-tetraene and 15-hydroxycembra-1,3,7,11-tetraene. By contrast, twenty conspecific pairs of overgrown and clean colonies of other alcyoniid soft corals collected from Pelorus Channel, Palm Island Group (18°34′S; 146°29′E), showed no chemical differences within in the pairs. Cultures of a common species of Ceramium [C. codii (Richards) Mazoyer] were incubated with different concentrations of nine soft-coral-derived diterpenes and significant algal growth inhibition was observed in many cases. It appears that terpenoids from soft coral may contribute to the lack of epizoic organisms on soft-coral polyparies. [ABSTRACT FROM AUTHOR]

Esterification of tetraene macrolide antibiotic nystatin A with organophosphorus alcohols has been studied; formation of the corresponding organophosphorus esters of the antibiotic has been confirmed. Physicochemical, spectral, and biological properties of the prepared esters have been studied. The esterification products have revealed high antifungal activity towards the Candida yeast fungi. [ABSTRACT FROM AUTHOR]

Mediated by AlCl3, substituted spiro[4.5]deca-tetraenes underwent novel and selective skeletal rearrangement to generate indene derivatives in high to excellent yields. [ABSTRACT FROM AUTHOR]

Preparations of Echinacea purpurea ( E. purpurea ) are widely used for the management of upper respiratory infections, influenza, and common cold, often in combination with other conventional drugs. However, the potential of phytochemical constituents of E. purpurea to cause herb-drug interactions via ABCB1 and ABCG2 efflux transporters remains elusive. The purpose of this study was to investigate the impact of E. purpurea -derived caffeic acid derivatives (cichoric acid and echinacoside) and tetraenes on the mRNA and protein expression levels as well as on transport activity of ABCB1 and ABCG2 in intestinal (Caco-2) and liver (HepG2) cell line models. The safety of these compounds was investigated by estimating EC 20 values of cell viability assays in both cell lines. Regulation of ABCB1 and ABCG2 protein in these cell lines were analyzed after 24 h exposure to the compounds at 1, 10, and 50 μg/mL. Bidirectional transport of 0.5 μg/mL Hoechst 33342 and 5 μM rhodamine across Caco-2 monolayer and profiling for intracellular concentrations of the fluorophores in both cell lines were conducted to ascertain inhibition effects of the compounds. Cichoric acid showed no cytotoxic effect, while the EC 20 values of tetraenes and echinacoside were 45.0 ± 3.0 and 52.0 ± 4.0 μg/mL in Caco-2 cells and 28.0 ± 4.3 and 62.0 ± 9.9 μg/mL in HepG2 cells, respectively. In general, the compounds showed heterogeneous induction of ABCB1 with the strongest 3.6 ± 1.2-fold increase observed for 10 μg/mL tetraenes in Caco-2 cells ( p < 0.001). However, the compounds did not induce ABCG2. None of the phytocompounds inhibited significantly net flux of the fluorophores across Caco-2 monolayers. Overall, tetraenes moderately induced ABCB1 but not ABCG2 in Caco-2 and HepG2 cells while no compound significantly inhibited activity of these transporters at clinically relevant concentration to cause herb-drug interactions.

Reaction of dienone (I) with two equivalents of N-phenylmaleimide proceeds as a sequence of two sequential Diels-Alder reactions furnishing the bis-adduct (III) in excellent yield. [ABSTRACT FROM AUTHOR]

Symmetrical spiro-1,3-bisketone (IV) is synthesized by ring-closure metathesis reaction of tetraene (I) obtained by Grignard reaction of a dialkenyl compound and allylmagnesium bromide. [ABSTRACT FROM AUTHOR]

A wide variety of primary and secondary amines are suitable nucleophiles for the title reaction to form ring opening products with good levels of enantioselectivity. [ABSTRACT FROM AUTHOR]

In vitro evaluation of a novel antimitotic estradiol analog and dichloroacetate in breast adenocarcinoma and breast nontumorigenic cells will contribute to the field of combination therapy in cancer. [ABSTRACT FROM AUTHOR]