Hexanal, precursor

Allen et al., 2001 investigated the effect of DLC coatings (obtained by fast-atom bombardment from a hexane precursor) deposited on polystyrene 24-well tissue culture plates on two osteoblast-like cell lines cultured on uncoated and DLC-coated plates for up to 72 h, by measuring the production of three osteoblast-specific marker proteins alkaline phosphatase, osteocalcin and type 1 collagen. According to Allen et al. (2001), there was no evidence that the presence of the DLC coating had an adverse effect on any of these measured parameters, which are indicative of metabolic processes in these osteoblast-Uke musculoskeletal system cells. 

The precursors dissolved in a hexane/ethyl acetate mixture (90 10, v/v) are adsorbed on a silica gel column that has been packed with hexane. The precursors were eluted with hexane/ethyl acetate mixtures, 80 20, 70 30, and 60 40 (v/v), in that order. 

For the deprotonation of less acidic precursors, which do not lead to mesomerically stabilized anions, butyllithium/TMEDA in THF or diethyl ether, or the more reactive, but more expensive,. seobutyllithium under these conditions usually are the most promising bases. Het-eroatomic substitution on the allylic substrate, which docs not contribute to the mesomeric or inductive stabilization often facilitates lithiation dramatically 58. In lithiations, in contrast to most other metalations, the kinetic acidity, caused by complexing heteroatom substituents, may override the thermodynamic acidity, which is estimated from the stabilization of the competing anions. These directed lithiations59 should be performed in the least polar solvent possible, e.g.. diethyl ether, toluene, or even hexane. 

A series of CoSx-MoSx/NaY catalysts was synthesized by intoducing Co(CO)3NO into MoSx/NaY evacuated at 673 K for 1 h, followed by second programmed sulfidation procedures. MoSx-CoSx/NaY catalysts were prepared in the reversed order of the metal sulfide accommodations into the zeolite cavities. When Co2(CO)g was used as the Co precursor, MoSx/NaY was impregnated with COj(CO)g dispersed in n-hexane, followed by evacuation at room temperature to remove the solvent. Co2(CO)g/MoSx/NaY was subsequently sulfided at 673 K to give CoSx/MoSx/NaY. The catalyst composition was determined by AAS and ICP. 

PtRu nanoparticles can be prepared by w/o reverse micro-emulsions of water/Triton X-lOO/propanol-2/cyclo-hexane [105]. The bimetallic nanoparticles were characterized by XPS and other techniques. The XPS analysis revealed the presence of Pt and Ru metal as well as some oxide of ruthenium. Hills et al. [169] studied preparation of Pt/Ru bimetallic nanoparticles via a seeded reductive condensation of one metal precursor onto pre-supported nanoparticles of a second metal. XPS and other analytical data indicated that the preparation method provided fully alloyed bimetallic nanoparticles instead of core/shell structure. AgAu and AuCu bimetallic nanoparticles of various compositions with diameters ca. 3 nm, prepared in chloroform, exhibited characteristic XPS spectra of alloy structures [84]. 

This chapter reports about an investigation on the catalytic gas-phase armnoxidation of u-hexane aimed at the production of 1,6-Ce dinitriles, precursors for the synthesis of hexamethylenediamine. Catalysts tested were those also active and selective in the ammoxidation of propane to aciylonitrile mtile-type V/Sb and SnA /Nb/Sb mixed oxides. Several A-containing compounds formed however, the selectivity to cyano-containing aliphatic linear Ce compounds was low, due to the relevant contribution of side reactions such as combustion, cracking and formation of heavy compounds. 

Elimination Procedures. Chemical redox-induced elimination was performed on precursor thin films by exposure to bromine or iodine vapor or by immersion of films in hexane solutions of these halides. 

On silylation/germylation of 17, compounds 18 were formed, which were subsequently lithiated on phosphorus to yield 16. It appears that the success of the next step from 16 to 15 depends on different factors, but the following three parameters may be regarded as critical (1) The reaction temperature for the elimination of LiF should not exceed 80°C (2) the concentration of 16 dissolved in hexane or toluene should be about <0.1 mol L (3) the steric bulk and electronic influence of the substituent attached to phosphorus should be optimized. In the first place, the nature of the substituent at phosphorus determines the structures of the precursors 16. This has been demonstrated by a study of a structure-reactivity... 

By contrast, deselenation of the bulkier precursor Tbt(Tip)GeSe4 72b with 3 molar amounts of triphenylphosphine in refluxing hexane under argon resulted in the quantitative isolation of the first stable germaneselone Tbt(Tip)Ge=Se 75 as red... 

Theoretical calculation at the HF/6-31G level99,102 on some S-S dications and their precursors have shown that the electronic structure of 1,4-dithionia-bicyclo[2.2.0]hexane and the sp-sp conformation of the tetramethyldisulfonium dication, the difference in the energy levels of [S] — [S] and [S] + n[S]103 is decreased owing to steric strain and the order of orbitals thus corresponds to case B. In the less strained systems (l,5-dithioniabicyclo[3.3.0]octane, 1,4-dithioniabicyclo[3.2.0]heptane), the order of orbitals corresponds to case C. Interestingly, ap-ap conformer of tetramethyldisulfonium dication was reported to correspond to case A. 

Radialene 52 has been envisaged as a precursor to hexaethynyl[3]radialene, a potential building block for carbon networks. However, desilylation under very mild conditions led to an unstable product of so far unknown identity. In this context, it should be mentioned that according to thermochemical calculations, the still unknown hexaethynyl[3]radialene has an increased conjugation energy with respect to vinylacetylene, probably because of partial relief of strain in the radialene corc26b. A remarkable aspect of 52 is its color the crystals are deep-red and a hexane solution has a purple color. In this respect, 52 differs from the yellow radialenes 50 and 51 and resembles [3]radialenes such as 27 and 38, which have much more extended --systems. 

Based on his previous work on the catalytic double addition of diazo compounds to alkynes173 using Cp RuCl(COD),174 Dixneuf has developed an efficient one-step synthesis of alkenyl bicyclo[3.1.0]-hexane derivatives of type 163 from enyne precursors 162 (Scheme 43). The catalytic cycle starts with the formation of an Ru=CHR species. It then adds to an alkyne to form ruthenacyclobutene 166, which evolves into vinylcarbene 167. [2 + 2]-Cycloaddition of 167 gives ruthenacyclobutane 168. The novelty in this transformation is the subsequent reductive elimination to give 170 without leading to the formation of diene 169. This can be attributed to the steric hindrance of the CsMes-Ru group. 

Preparation of 4-(l-phenvlethvloxvl-stvrene. This benzylic ether of p-hydroxystyrene was prepared by a Wittig reaction on the precursor aldehyde as described above. The final product was obtained in 73% yield after purification by preparative HPLC using 5% ethyl acetate in hexane as eluent. The product had analytical characteristics in agreement with the proposed structure. 

---