Azetidinyl ketone chemistry. C-Methylation reactions and stereostructure - spectra relationships

The C-methylation of the potassium salt of 1-t-butyl-2-phenyl-3-(p-phenylbenzoyl)azetidine ( 1a ) with methyl iodide was studied in three solvents, and the stereochemical outcome of the reaction was shown to be dependent upon the solvent used. These results are rationalized in terms of the probable relative rates of the reaction in the various solvents and/or the effect of solvent on the structure of the anionic intermediate. Similar treatment of the potassium salt of 1-t-butyl-2-phenyl-3-benzoylazetidine ( 3a ) in ethyl ether gave a comparable result. The configurations of the epimeric C-methyl products ( 2a and 2b , and 4a ) were assigned on the basis of their spectral properties. With the aid of spectral data for a model compound, l-t-butyl-3-benzoyl-azetidine ( 5 ), several stereostructure-spectra relationships for 3-azetidinyl ketones are presented.     

The role of solvent in conjugate additions leading to cis and trans-1-Alkyl-2-aryl-3-carbo(aroyl)aziridines

In the formation of cis- and trarn-1-alkyl-2-aryl-3-carbo(aroyl)aziridines a change in solvent from benzene to rnethanol in the α-bromochalone-primary amine reaction produced an increase in cic isotner. However, the same solvent change resulted in a decrease in the cis/trans ratio when these same aziridines were prepared by the ehalcone-halogen-primary amine reaction. These results are rationalized in terms of both an open and chelated enol intermediate thought to be crucial in the relative product formations. Other mechanistic considerations in the product formations are presented.     

Investigations into sulfobetaine-stabilized Cu nanoparticle formation: toward development of a microfluidic synthesis

The mechanistic aspects of the formation of sulfobetaine-stabilized copper nanoparticles were investigated by using in situ XANES (X-ray absorption near edge structure), UV-vis spectroscopy, and reaction calorimetry. The tetracoordinated sulfobetaine-Cu(II) complex was reduced to a stable sulfobetaine-Cu(I) complex prior to the formation of sulfobetaine-stabilized copper nanoparticles. The stability of the Cu(I) complex was found to be sensitive to the concentration of the sulfobetaine stabilizer and the addition rate of the reducing agent. It appears to exist primarily as a linear complex. A tetracoordinated Cu(I) complex as an intermediate has also been postulated. Based on the understanding from these investigations, a microfluidic process for copper nanoparticle synthesis was designed by using sulfobetaine-Cu(I) complex as the starting material. When compared with the copper nanoparticles synthesized by a conventional batch process, the microfluidic reactor process provided particles with a smaller size and narrower size distribution. The copper nanoparticles from the microreactor process could also be more easily purified and the particles were relatively stable in air. Both XRD and SAED indicated that the Cu nanoparticles synthesized have fcc structure.     

Synthesis and characterization of S-Au interaction in gold nanoparticle bound polymeric beads

A detailed X-ray Absorption Spectroscopic examination of S-Au interaction in gold nanoparticle bound to Polystyrene-Divinyl Benzene (PS-DVB) micro beads was carried out. Gold nanoparticles were bound to the surface of the commercially available PS-DVB beads using a simple one step procedure. Influence of polystyrene backbone on the electronic structure of the gold nanoparticles was observed through X-ray Absorption Near Edge Structure (XANES) spectra of Au at L III edge. An additional structure in the white line of the S K-edge XANES spectrum confirmed the presence of S-Au bonding. Transmission Electron Microscopy (TEM) studies coupled with Selected Area Electron Diffraction Pattern and X-ray Diffraction studies revealed the morphology of the Au nanoparticles bound to the micro beads.     

Conversion of 3,n-dithiabicyclo[n.3.1]alkatrienes to bicyclo[n.3.1]alkapentaenes

The application of the Ramberg-Backlund reaction in the conversion of several 3,n-dithiabicyclo[n.3.1]alkatrienes to the corresponding bicyclo[n.3.1]alkapentaenes is reported. Proton magnetic resonance and ultraviolet spectra were utilized in the overall characterization of bicyclo[8.3.1]tetradeca-2,8,10,12,1(14)-pentaene, bicyclo[9.3.1]pentadeca-2,9,11,1(15)-pentaene, and their precursors. The final step in the synthesis was a Ramberg-Backlund of bis-α,α′-chloro sulfone. The intermediate, 2-chloro-3-thiabicyclo[9.3.1]pentadeca-9,11,13,1(15)-tetraene 3,3-dioxide, was isolated and characterized. The structure and stability of the bridged α,α′-dichloro sulfide intermediates were examined.