A cytotoxicity test protocol for single-wall nanotubes (SWNTs), multi-wall nanotubes (with diameters ranging from 10 to 20 nm, MWNT10), and fullerene (C60) was tested. Profound cytotoxicity of SWNTs was observed in alveolar macrophage (AM) after a 6-h exposure in vitro. The cytotoxicity increases by as high as approximately 35% when the dosage of SWNTs was increased by 11.30 microg/cm2. No significant toxicity was observed for C60 up to a dose of 226.00 microg/cm2. The cytotoxicity apparently follows a sequence order on a mass basis: SWNTs > MWNT10 > quartz > C60. SWNTs significantly impaired phagocytosis of AM at the low dose of 0.38 microg/cm2, whereas MWNT10 and C60 induced injury only at the high dose of 3.06 microg/cm2. The macrophages exposed to SWNTs or MWNT10 of 3.06 microg/cm2 showed characteristic features of necrosis and degeneration. A sign of apoptotic cell death likely existed. Carbon nanomaterials with different geometric structures exhibit quite different cytotoxicity and bioactivity in vitro, although they may not be accurately reflected in the comparative toxicity in vivo.

The selective conversion of carbon-oxygen bonds into carbon-nitrogen bonds to form amines is one of the most important chemical transformations for the production of bulk and fine chemicals and pharma intermediates. An attractive atom-economic way of carrying out such C-N bond formations is the direct N-alkylation of simple amines with alcohols by the borrowing hydrogen strategy. Recently, transition metal complexes based on precious metals have emerged as suitable catalysts for this transformation; however, the crucial change towards the use of abundant, inexpensive and environmentally friendly metals, in particular iron, has not yet been accomplished. Here we describe the homogeneous, iron-catalysed, direct alkylation of amines with alcohols. The scope of this new methodology includes the monoalkylation of anilines and benzyl amines with a wide range of alcohols, and the use of diols in the formation of five, six-and seven-membered nitrogen heterocycles, which are privileged structures in numerous pharmaceuticals.

Put a label on it: Carbon dioxide with H2 is shown to be an efficient and selective methylation reagent for aromatic and aliphatic amines (see scheme; acac=acetylacetonate, triphos = 1,1,1‐tris(diphenylphosphanylmethyl)ethane). A variety of functionalized amines including 13C‐labelled drugs were obtained with good yields and functional‐group tolerance.

We develop a novel strategy to more effectively and controllably process continuous enzymatic or homogeneous catalysis reactions based on nonaqueous Pickering emulsions. A key element of this strategy is "bottom-up" construction of a macroscale continuous flow reaction system through packing catalyst-containing micron-sized ionic liquid (IL) droplet in oil in a column reactor. Due to the continuous influx of reactants into the droplet microreactors and the continuous release of products from the droplet microreactors, catalysis reactions in such a system can take place without limitations arising from establishment of the reaction equilibrium and catalyst separation, inherent in conventional batch reactions. As proof of the concept, enzymatic enantioselective trans-esterification and CuI-catalyzed cycloaddition reactions using this IL droplet-based flow system both exhibit 8 to 25-fold enhancement in catalysis efficiency compared to their batch counterparts, and a durability of at least 4000 h for the enantioselective trans-esterification of 1-phenylethyl alcohol, otherwise unattainable in their batch counterparts. We further establish a theoretical model for such a catalysis system working under nonequilibrium conditions, which not only supports the experimental results but also helps to predict reaction progress at a microscale level. Being operationally simple, efficient, and adaptive, this strategy provides an unprecedented platform for practical applications of enzymes and homogeneous catalysts even at a controllable level.

CA). Mass spectra were recorded on an AEI-MS-902 mass spectrometer (EI+) or a LTQ Orbitrap XL (ESI+). Conversions were determined by GC-FID (GC: HP 6890) with an HP-5 column (Agilent Technologies, Palo Alto, CA). GC-MS and GC-FID analysis method: 60 o C 5 min, 180 o C 5 min (10 o C/min), 260 o C 5 min (10 o C/min). 1 Hand 13 C NMR spectra were recorded on a Varian AMX400 (400 and 100.59 MHz, respectively) using CDCl 3 , CD 3 OD, or CD 2 Cl 2 as solvent. Chemical shift values are reported in ppm with the solvent resonance as the internal standard (CDCl 3 : 7.26 for 1 H, 77.00 for 13 C; CD 3 OD: 3.31 for 1 H, 49.00 for 13 C; CD 2 Cl 2 : 5.32 for 1 H, 53.84 for 13 C). Data are reported as follows: chemical shifts, multiplicity (s = singlet, d = doublet, t = triplet, q = quartet, br. = broad, m = multiplet), coupling constants (Hz), and integration. All reactions were carried out under an Argon atmosphere using oven (110 o C) dried glassware and using standard Schlenk techniques. THF and toluene were collected from a MBRAUN solvent purification system (MB SPS-800). Dioxane (99.5%, extra dry), dichloroethane (DCE, 99.8%, extra dry), N,N-dimethylformamide (DMF, 99.8%, extra dry) and acetonitrile (CH 3 CN, 99.9%, extra dry) were purchased from Acros without further purification. Molecular sieves 4A were purchased from Acros, and heated in Schlenck under 180 o C in vacuo overnight for activation before using. All other reagents were purchased from Sigma or Acros in reagent or higher grade and were used without further purification. Complex Cat 1 was synthesized according to literature procedures 1 with slightly modification. Representative proceduresGeneral procedure: An oven-dried 20 ml Schlenk tube, equipped with stirring bar, was charged with amine (0.5 mmol, 1 equiv), alcohol (given amount), iron complex Cat 1 (4 -6 mol %), Me 3 NO (8 -12 mol %) and Toluene (solvent, 2 ml). The solid starting materials were added into the Schlenk tube under air, the Schlenk tube was subsequently connected to an argon line and a vacuum-argon exchange was performed three times. Liquid starting materials and solvent were charged under an argon stream followed by addition of 95 -105 mg activated molecular sieves 4A. The Schlenk tube was capped and the mixture was rapidly stirred at room temperature for 1 minute, then was placed into a pre-heated oil bath at the appropriate temperature and stirred for a given time. The reaction mixture was cooled down to room temperature and the crude mixture was filtered through celite, eluted with ethyl acetate, and concentrated in vacuo. The residue was purified by flash column chromatography to provide the pure amine product.

Formation of C-C bonds from CO2 is a much sought after reaction in organic synthesis. To date, other than C-H carboxylations using stoichiometric amounts of metals, base, or organometallic reagents, little is known about C-C bond formation. In fact, to the best of our knowledge no catalytic methylation of C-H bonds using CO2 and H2 has been reported. Described herein is the combination of CO2 and H2 for efficient methylation of carbon nucleophiles such as indoles, pyrroles, and electron-rich arenes. Comparison experiments which employ paraformaldehyde show similar reactivity for the CO2/H2 system.

We present a method for N-alkylation of unprotected amino acids with alcohols with excellent yield and stereochemistry retention.

In Kombination mit H2 entpuppt sich Kohlendioxid als effizientes und selektives Methylierungsreagens für aromatische und aliphatische Amine (siehe Schema; acac=Acetylacetonat, triphos=1,1,1‐Tris(diphenylphosphanylmethyl)ethan). Eine Vielfalt funktionalisierter Amine, einschließlich 13C‐markierter Wirkstoffe, wurde in guten Ausbeuten bei hoher Verträglichkeit mit funktionellen Gruppen erhalten.