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This paper reports one-pot synthesis of 2,2,2-trifluoroethyl 1H -pyrazole-5(3)-carboxylates via cyclocondensation of 1,1,1-trichloro-4-alkoxy-3-alken-2-ones [Cl 3 CC(O)C(R 2 ) = C(R 1 )OMe, where R 1 = H, CH 3 , n -octyl, n -nonyl, n -decyl, n -undecyl, n- tridecyl, −(CH 2 ) 2 Ph, 4-ClC 6 H 4 , 4-BrC 6 H 4 and R 2 = H] and 1,1,1-trichloro-2,4-alkanediones, 1-aryl-4,4,4-trichloro-1,3-butanediones [Cl 3 CC(O)CHR 2 C(O)R 1 , where R 1 = H, CH 3 , −(CH 2 ) 2 Ph, Ph, 4-FC 6 H 4 , 4-BrC 6 H 4 , R 2 = H, R 1 = Ph and R 2 = CH 3 and R 1 , R 2 = cyclo-(CH 2 ) 5 -] with hydrazine hydrochloride in 2,2,2-trifluoroethanol (TFE). Considering the low nucleophilicity of TFE in relation to methanol or ethanol, the results provide evidence for the mechanism of hydrolysis of the trichloromethyl group attached to the 1 H -pyrazol ring.

A series of 2,4,6-trisubstituted phenols 7a–7p has been prepared in moderate to good yields (23–77 %) by a retro-Diels–Alder reaction from hindered tricyclic alcohols 6a–6q, using mild acidic conditions. The tricyclic alcohols were obtained by reduction of highly functionalized cyclohexadienones 5a–5q, which in turn were regioselectively prepared under mild conditions in high yields by treatment of a series of stable chromium(0) and tungsten(0) Fischer dienyl carbenes 4a–4g with different terminal alkynes 3a–3l. Carbenes 4a–4g were prepared by a [4+2] cycloaddition of alkynylethoxy carbene complexes 1a–1g with 1,2,3,4,5-pentamethylcyclopentadiene (2). In a complementary route, compounds 5a–5q were also obtained by a multicomponent reaction in yields similar to those obtained in the multistep process (25–84 %), starting from 1a–1g, 2, and 3a–3l. The phenol products have a wide range of potential applications, and may be useful intermediates for further transformations.

A simple and convenient method to generate 4-aryl-substituted 1H-2-(trichloromethyl)-1,3-diaza-1,3-butadienes from aryl(chlo­ro)methaniminium salts (best known as Vilsmeier–Haack reagents) and trichloroacetamidine has been developed. These 4-aryl-1H-1,3-diaza­butadienes are isolable, relatively stable during silica gel chromatography, and can be crystallized. The analysis by X-ray diffraction demonstrated that in the solid state these 1,3-diazabutadienes have an s-cisoid conformation. The principal characteristic of these 1,3-diazabutadienes is their reactivity towards electron-deficient acetylenes, reacting under mild reaction conditions to produce 4-aryl-2-(trichloromethyl)pyrimidines in good yields.

Activated carbons belong to the most widely used adsorbent materials. The utility of these materials mainly depends on their chemical surface and porous structure. The method of activation and the nature of the used precursor greatly influence the pore structure and surface functional groups of the activated carbon. Therefore, the main objective of current investigations is to develop or modify the activation method in an optimal manner using appropriate precursors. This review compiles the results of various studies on the synthesis of activated carbons from agricultural waste. Various activation methods, such as physical, chemical, physicochemical, and microwave activation, are discussed. The effects of carbonization and activation parameters, such as temperature, activating agent, and residence time, toward the properties of the activated carbon are reviewed.

An efficient and simple synthesis of novel and densely substituted N-benzyl-1H-pyrroles 6a–r is described by a 1,4-addition/isomerization/ring closure/demetalation cascade process of alkynyl Fischer carbene complexes 1a–f and 2a and α-imino glycine methyl esters 3a, b, d, g, h, and k promoted with LDA.

Enantiomerically pure carbamate-monoprotected trans -cyclohexane-1,2-diamines are used as chiral organocatalysts for the addition of aryl ketones and acetone to nitroalkenes to give enantioenriched β-substituted γ-nitroketones. The reaction was performed in the presence of 3,4-dimethoxybenzoic acid as an additive, in chloroform as the solvent at room temperature, achieving enantioselectivities up to 96%. Theoretical calculations are used to justify the observed sense of the stereoinduction.

This work was financially supported by the University of Alicante (VIGROB-173, GRE12-03, UAUSTI13-01, UAUSTI13-02).

A simple change in the polarity of the solvent allows both enantiomers of substituted succinimides to be obtained in the enantioselective conjugate addition reaction of aldehydes, mainly α,α-disubstituted, to maleimides catalyzed by chiral carbamate-monoprotected trans-cyclohexane-1,2-diamines.

A facile, one-pot, ultrasound-promoted synthesis of N-substituted 5-(3,3,3-trifluoro-2-oxopropylidene)pyrrolidin-2-ones from methyl 7,7,7-trifluoro-4-methoxy-6-oxohept-4-enoate and a wide range of primary alkyl(aryl)amines using ethanol as a green solvent and employing triethylamine as a base is described.

Enantiomerically pure mono-N-Boc-protected trans-cyclohexa-1,2-diamines are used as organocatalysts for the enantioselective conjugate addition of α,α-disubstituted aldehydes to maleimides. Using a single enantiomer of the organocatalyst, both enantiomeric forms of the resulting Michael adducts bearing a new quaternary stereocenter are obtained in high yields, by only changing the reaction solvent from chloroform (up to 86% ee) to aqueous DMF (up to 84% ee).

The regiospecific synthesis and isolation of three series of 5-trichloromethyl-pyrazoles 2f–j, 3a–j and 4a–j from the cyclocondensation of 1,1,1-trichloro-4-alkoxy-3-alken-2-ones (1a–f) or trichloroacetyl containing β-diketones (1g–j) with dry hydrazine and phenyl-hydrazine is reported. It was established by 1H- and 13C-NMR spectroscopy that the 5-hydroxy-5-trichloromethyl-4,5-dihydro-1H-pyrazole intermediates 2a–j were formed quantitatively.

A new series of brominated 3,4-polymethylene-5-hydroxy-5-trichloromethyl-4,5-dihydroisoxazoles (2a–d) has been regiospecifically obtained from the reaction of ω-bromo-2-trichloroacetylcycloalkanones with hydroxylamine in 79–87% yield. Dehydration of the 5-hydroxydihydroisoxazoles 2a–d can be effected with concentrated sulfuric acid at 25 °C to give the regioisomeric brominated 3,4-polymethylene-5-trichloromethylisoxazoles (3a–d). In contrast, the dehydration of 5-hydroxydihydroisoxazoles with sulfuric acid in ethanol solution at 65 °C, for transformation of trichloromethyl to carboxyl group, was reproducible only with 9-bromo-3-trichloromethyl-3,3a,4,5,6,7,8,9-octahydrocycloocta[c]isoxazole-3-ol, 2d, leading to isoxazolecarboxylate 4d. The structural assignments of all isolated products are based on the analysis of their 1H and 13C NMR spectral data.

The first gas-phase high-resolution FTIR spectra of S2N2 (D2h) is presented together with a high-level quantum mechanical and experimental study of its molecular ground-state and equilibrium structures.

This account describes the developments on the synthesis and reactivity of functionalized 2,8-diheterobicyclo[3.2.1]octanes. The continued interest in the chemistry of these compounds is mainly due to their abundance in Nature, being at the core of numerous families of biologically active natural products, and also as a result of their versatile reactivity, which makes them very useful building blocks with considerable impact in modern organic synthesis. The present article is aimed toward providing a comprehensive coverage of the literature on these heterocyclic scaffolds, including our own contributions, and has been organized according to the nature of the heteroatom embedded in the 2,8-bicyclo[3.2.1]octane framework. 1 Introduction 2 2,8-Dioxabicyclo[3.2.1]octane Systems 2.1 Natural Products 2.1.1 Marine Origin: Pectenotoxins, Saliniketals 2.1.2 Terrestrial Origin: Fungus (Squalestatins), Plants 2.2 Synthetic Products 3 2-Aza-8-oxabicyclo[3.2.1]octane Systems 3.1 Cyclonucleotides 3.2 Diazaimide Derivatives 3.3 Systems with a 1,3-Oxazepane Core 3.4 2-Aza-8-oxabicyclo[3.2.1]octanes Fused with Aromatic Rings 3.5 Other Bicyclic Systems 4 2-Thia-8-oxabicyclo[3.2.1]octane Systems 4.1 From Sugars 4.2 Compounds for Asymmetric Epoxidation 4.3 Compounds from Photoreactions of Thioketones 5 2-Oxa-8-azabicyclo[3.2.1]octane Systems 5.1 Natural Products: Kopsia Alkaloids 5.2 Synthetic Products 6 2,8-Diazabicyclo[3.2.1]octane Systems 6.1 Natural Products: Albomitomicyn 6.2 Synthetic Products: Epibatidine Analogues 7 2-Thia-8-azabicyclo[3.2.1]octane Systems 7.1 Natural Products: Diketopiperazines 7.2 Synthetic Products 8 Conclusions

The new solid solution Gd2(Co3-xSix) (0.29 < x < 0.50) is obtained by arc-melting of the elements.

Diazabutadiene react with aluminum halides in toluene to furnish ionic aluminum coordination compounds [cf.

An Fe-catalyzed conversion of aldehydes to ketones via [1,2]-shift has been developed. This skeletal rearrangement shows a wide substrate scope and chemoselectivity profile while exhibiting an excellent [1,2]-aryl or [1,2]-alkyl shift selectivity that is easily switched by electronic effects.

Coupling of chiral sulfur ylides of type (VII) with aldehydes provides an efficient and highly diastereoselective approach to aryl and alkyl trans-epoxyamides.

This work describes the synthesis of a novel series of 2-methylsulfanyl-tetrahydropyrimidines, from the cyclocondensation reaction of β-alkoxyvinyl trihalomethyl ketones with 2-methyl-2-thiopseudourea sulfate, in good yields. A detailed 1H- and 13C-NMR study was performed on the 2-methylsulfanyl-tetrahydropyrimidines obtained and 3D structures were proposed based on AM1 calculations supported by 1H NMR coupling constants and NOESY experiments.

The authors gratefully acknowledge FSE, MICINN CTQ2009-11172BQU, Junta de Castilla and Leon (SA162A12-1) for financial support. MFF is grateful to the JCyL-ESF for her FPI fellowship. JP is grateful to MINECO for a FPU fellowship. P.G-G. is grateful for a JAE-DOC contract from CSIC co-funded by the European Social Fund (ESF)

Novel C2-symmetric bis-sulfoxide/N-oxide (R,R)-5 was prepared in good yield according to the Andersen protocol with (S)-menthyl p-tolyl sulfinate (2 equiv) and the dilithium derivate of 2,6-dimethylpyridine N-oxide. Reduction of (R,R)-5 to pyridine/bis-sulfoxide (R,R)-6 was accomplished by means of Katritzky’s procedure (Fe0/AcOH). Both bis-sulfoxides (R,R)-5 and (R,R)-6 are efficient chiral organocatalysts in the asymmetric allylation of N-benzoyl hydrazones derived from both aldehydes and ketones.

Reaction of 4-trichloromethyl-1H-pyrimidin-2-ones with 5-bromo-1,1,1-trichloro(fluoro)-4-methoxy-alk-3-en-2-ones affords 1-(5,5,5-trichloro(fluoro)-2-methoxy-4-oxopent-2-en-1- yl)-4-trichloromethyl-1H-pyrimidin-2-ones. Reaction of the latter trichloromethylated compound with amines, hydroxylamine, and hydrazines affords a series of 1-(2-alkylamine-5,5,5-trichloro-4- oxopent-2-en-1-yl)-4-trichloromethyl-1H-pyrimidin-2-ones and 1-(5-trichloromethyl-5-hydroxy-4,5-dihydro-3-azol-3-ylmethyl)-4- trichloromethyl-1H-pyrimidin-2-ones, respectively.

The regiospecific synthesis of a novel series of 4-trifluoro[chloro]-2-(5-hydroxy-5-trifluoro[chloro]methyl-4,5-dihydro-1H-pyrazol-l-y1]-pyrimidines from the reactions of 4-alkoxy-1,1,1 -trifluoro[chloro]-alk-3-en-2-ones with 6-trifluoro(chloro]methyl-2-hydrazine pyrimidines is presented.

Polyhydroxylated pyrrolidines are synthesized in a one-pot procedure by addition of an organometallic reagent to isoxazolidines obtained by 1,3-dipolar cycloaddition between nitrones and vinylsulfones.

β-Enaminones have been synthesized by the condensation reaction of β-diketones with various anilines in the presence of a catalytic amount of formic acid, mild and highly efficient acid catalyst in methanol. These condensation reactions proceed smoothly in short reaction times with near-quantitative yields. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.

Reaction of 1,1,1-trichloro-4-methoxy-3-alken-2-ones with hydroxylamine hydrochloride leads to a rapid one-pot synthesis of 5-trichloromethylisoxazoles.

Benzocyclobutenones are an intriguing class of four-membered-ring ketones that have been used extensively as powerful synthetic intermediates in organic synthesis. Their high reactivity is primarily attributed to the unique high electrophilicity of the carbonyl unit and the ability to generate o-quinone dimethides, allowing a myriad of different transformations. However, the synthesis of benzocyclobutenones still represents a great challenge. This review provides an overview of the preparation, use and impact of benzocyclobutenones in organic synthesis. Selected applications in the synthesis of natural products are also described, in order to illustrate the utility of these compounds. 1 Introduction 2 Synthetic Methods for Preparing Benzocyclobutenones 2.1 [2+2]-Type Cycloadditions 2.2 Metal-Mediated Intramolecular Cyclizations 2.3 Metal-Catalyzed Cross-Coupling Reactions 2.3.1 Carbon–Hydrogen Bond-Functionalization Events 2.3.2 Stille Cross-Coupling Reactions 2.4 Other Synthetic Methods for Preparing Benzocyclobutenones 3 Synthetic Application of Benzocyclobutenones and Related Compounds 3.1 Synthesis of Polycyclic Compounds via o-Quinone Dimethides 3.1.1 Synthesis of α-Tetralones 3.1.2 Synthesis of Benzo[n]annulenes 3.1.3 Synthesis of Naphthalene Derivatives 3.1.4 Synthesis of Anthraquinones 3.1.5 Synthesis of Benzodiazepines 3.1.6 Synthesis of Tetrahydronaphthalenes 3.1.7 Synthesis of Isochromanones 3.2 Synthesis of Fused Rings via Non-Electrocyclization Techniques 3.2.1 Ring Expansions from Four- to Five-Membered Rings 3.2.2 Ring Expansions from Four- to Six-Membered Rings 3.3 Other Synthetic Applications 3.3.1 Tricarbonylchromium Complexes 3.3.2 Base-Induced Carbon–Carbon Bond Cleavage 3.4 Benzocyclobutenones and Their Derivatives in Natural Product Synthesis 4 Conclusions

Under conditions A), ether aromatic chlorides of type (I), (VII), and (IX) undergo new, site-selective intramolecular cyclization to benzocyclobutenones.

Available data on the iron-containing nanomaterials are reviewed. Main attention is paid to the following themes: synthetic methods, structures, composition and properties of the nano zerovalent iron (NZVI), and polymorphic forms of iron oxides and FeOOH. Synthetic methods summarized here include a series of physico-chemical methods such as microwave heating, electrodeposition, laser ablation, radiolytical techniques, arc discharge, metal-membrane incorporation, pyrolysis, combustion, reverse micelle and co-deposition routes. We have also included a few “greener” methods. Coated, doped, supported with polymers or inert inorganic materials, core–shell nanostructures, in particular those of iron and its oxides with gold, are discussed. Studies of remediation involving iron-containing nanomaterials are discussed and special attention is paid to the processes of remediation of organic contaminants (chlorine-containing pollutants, benzoic and formic acids, dyes) and inorganic cations (Zn(II), Cu(II), Cd(II) and Pb(II)) and anions (nitrates, bromates, arsenates). Water disinfection (against viruses and bacteria), toxicity and risks of iron nanomaterials application are also examined.

Suzuki—Miyaura cross-coupling of ester (I) with aryl bromides and iodides under continuous flow conditions provides biphenyl derivatives (III).

A one-pot stibine modified Co 2 (CO) 8 homogeneous catalytic reductive N-alkylation of primary amides using aldehydes/ketones as alkylating agents, is reported. Good to excellent yields of a wide range of secondary amides are obtained (up to 97%) under relative mild conditions.

The title compound is synthesized by Li+/H+ ion exchange of Li2Ti6O13 using benzoic acid (125 °C in air, 72 h).

Condensation of unsaturated esters (I) and (VII) with 1,2-diamines proceeds in the presence of trimethylaluminum providing imidazolines (III) and (VIII) which are further allylated giving suitable dienes (V) and (IX).

Ethyl E-2-acyl-3-ferrocenylacrylates react with 1,1-dimethylguanidine and acetamidine to yield novel 1,3-insertion products of 5-ferrocenyl-2,4-diaza-1,7-dioxohept-2-ene type.

The 3-bromolactam (I) derived from (R)-2-phenylglycinol undergoes a stereoselective reaction with arylcuprate reagents.

Mixture of oxiranes (I), which are difficult to separate (no details given), allow a regiospecific synthesis of oxazepanones and morpholinones.

The high regioselectivity of the reaction of α-ferrocenylmethylidene-β-oxocarboxylates (I) with N-monoalkylhydrazines (II) is noteworthy.