A simple,direct synthesis of Na2Fe(CO)4

Summary Reduction of anhydrous FeCl₃ in THF with sodium naphthalenide under a CO atmosphere at room temperature leads directly to Na₂Fe(CO)₄, which on reaction with alkyl bromides gives the corresponding aldehydes, ketones and carboxylic acids under appropriate conditions.     

Synthesis of Amines by Reduction of Imines with the MCl2/NaBH4 (M = Co,Ni) System

A simple method for the synthesis of amines by the reduction of imines, anils and enamines, including some chiral substrates, with the MCl₂/NaBH₄/CH₃OH reagent (M = Co, Ni) in 64–82% yields is described.     

DSC analysis of Al6061 aluminum alloy powder by rapid solidification

Differential scanning calorimetry (DSC) is a powerful technique that measures the heat evolution from a sample under a controlled condition and studies the phase transformation, precipitation, and dissolution activities. In this work, we investigated the influence of admixed silicon and silicon carbide and the effect of different atmospheres on the heat flow properties and microstructure of atomized Al6061 powder using DSC and scanning electron microscopy. The DSC analysis revealed the addition of silicon considerably decreased the temperature of first endothermic peaks. With an increase in silicon content the enthalpy for the first endothermic peak increased, whereas the second endothermic peak decreased. An endothermic peak, indicating the formation of AlN, was observed for powders without the silicon addition, but was noticeably absent in the case of alloys with Si addition. The SiC addition has no influence on changing the enthalpy of the systems we investigated. The reason for this behavior is analyzed and presented in this article.     

Preparation of Functionalized Dialkylzincs via a Boron-Zinc Exchange. Reactivity and Catalytic Asymmetric Addition to Aldehydes

The hydroboration of olefins with Et(2)BH provides diethyl(alkyl)boranes 2 which readily undergo a boron-zinc exchange with Et(2)Zn providing a range of polyfunctional primary, secondary, and benzylic diorganozincs. The resulting diorganozincs 3 have been reacted with various electrophiles (allylic halides, acid chlorides, alkylidenemalonates, ethyl propiolate, nitroolefins) in the presence of CuCN.2LiCl with excellent yields. With secondary dialkylzincs prepared from diastereomerically pure diethyl(alkyl)boranes, the boron-zinc exchange occurs with loss of stereochemistry. The asymmetric addition of 3 to aldehydes in the presence of the chiral catalyst 55 furnishes optically active polyfunctional secondary alcohols (50 to over 96% ee).     

New Method for the Generation and Trapping of 1-Azabicyclo[1.1.0]butane. Application to the Synthesis of 1,3-Dinitroazetidine

1-Azabicyclo[1.1.0]butane (1) has been prepared via a two-step, one-pot procedure that involves (i) reaction of a heptane solution of allylamine with N-chlorosuccinimide at 0 °C followed by (ii) codistillation of the product from basic solution along with heptane-octane. Compound 1 thereby obtained was extracted from the distillate by using cold aqueous NaNO₂. Subsequent treatment of the aqueous extract with cold concentrated aqueous HCl afforded N-nitroso-3-nitro-azetidine (4) in 5.5% yield. Oxidation of 4 with 100% HNO3 produced N,3-dinitroazetidine (5, 90%). This reaction sequence constitutes a formal synthesis of 1,3,3-trinitroazetidine (TNAZ), an important energetic material.     

Synthesis of N-Substituted Azetidin-3-ones

Addition of RC(0)Cl (R = OEt, Me, or Ph) across the highly strained N-C(3) o-bond in 3-bromomethyl-l-azabicyclo[1.1.0]butane (1) afforded the corresponding N-acyl-3-bromomethyl-3-chloroazetidines (2a-2c, respectively). Subsequent zinc promoted eliminative dehalogenation of 2a-2c produced the corresponding N-acyl-3-methyleneazetidines (3a-3c, respectively). Finally, ozonolysis of 3a-3c afforded the corresopnding N-acylazetidin-3-ones (4a-4c, respectively).     

TG–DSC–FTIR–MS study of gaseous compounds evolved during thermal decomposition of styrene-butadiene rubber

The thermal decomposition behavior of styrene-butadiene rubber was studied using a system equipped with thermogravimetric analysis, differential thermal analysis, Fourier transform infrared spectroscopy, and mass spectroscopy. Two different experiments were conducted. From these experiments, thermogravimetric analysis results indicated a mass loss of 58 % in the temperature range of ~290–480 °C and a mass loss of 39 % in the temperature range beyond 600 °C. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy confirmed the presence of oxides, even at 1,000 °C, accounting for the Zn, Mg, Al, Si, and Ca in the original sample.     

Enhanced Production of Laccase from Coriolus versicolor NCIM 996 by Nutrient Optimization Using Response Surface Methodology

Plackett and Burman design criterion and central composite design were applied successfully for enhanced production of laccase by Coriolus versicolor NCIM 996 for the first time. Plackett and Burman design criterion was applied to screen the significance of ten nutrients on laccase production by C. versicolor NCIM 996. Out of the ten nutrients tested, starch, yeast extract, MnSO(4), MgSO(4) x 7H(2)O, and phenol were found to have significant effect on laccase production. A central composite design was applied to determine the optimum concentrations of the significant variables obtained from Plackett-Burman design. The optimized medium composition for production of laccase was (g/l): starch, 30.0; yeast extract, 4.53; MnSO(4), 0.002; MgSO(4) x 7H(2)O, 0.755; and phenol, 0.026, and the optimum laccase production was 6,590.26 (U/l), which was 7.6 times greater than the control.     

Crystallization and X-Ray Diffraction Studies of Salmonella Invasion Protein D (SipD), Insight Tip Component of Salmonella typhi Type III Secretion System

Crystallography Reports - Many pathogenic gram-negative bacteria including Salmonella typhi utilize type III secretion systems (T3SSs) to inject bacterial proteins into host cells and to initiate...     

Intermolecular [2+2] photocyclization of ethyl 5-oxo-1a,2,5,5a,6,6a-hexahydro-2,6-methano-2aH-indeno-[5,6-b]oxirene-2a-carboxylate

The photodimer, 7, of ethyl 5-oxo-1a,2,5,5a,6,6a-hexahydro-2,6-methano-2aH-indeno-[5,6-b]oxirene-2a-carboxylate has been isolated and structuraally characterized. Triclinic,P ^?1,a=9.7783(6),b=11.2782(7),c=11.3445(7) Å, α=105.461(9), β=113.3759(10), γ=92.9155(11)^o,V=1089.36(12) ų,R=0.049 for 3557 unique observed reflections. Two independent molecules lying on inversion centers occupy the unit cell. The influence of the orientation of the ester group on the polycyclic skeleton is discussed.