Synthesis and reactivity of N-acyl-5- (1-hydroxyalkyl)-2,3-dihydro-4-pyridones

[structure: see text]. The Nozaki-Hiyama-Kishi reaction was used to prepare the 5-(1-hydroxyalkyl)-2,3-dihydro-4-pyridones 3. Reduction, oxidation, and substitution reactions of 3 were examined.     

The Mukaiyama-Michael reaction of N-acyl-2,3-dihydro-4-pyridones: regio- and stereoselective synthesis of cis-2,6-disubstituted 1,2,5,6-tetrahydropyridines

[formula: see text] A convenient regio- and stereoselective preparation of 1,2,5,6-tetrahydropyridines of the type 1 has been developed, starting from readily available N-acyl-2,3-dihydro-4-pyridones 2.     

Diels-Alder reactions of 5-vinyl-1-acyl-2-aryl-2,3-dihydro-4-pyridones: regio- and stereoselective synthesis of octahydroquinolines

[reaction: see text] Readily available 5-vinyldihydropyridones 2 undergo Diels-Alder cyclization with various dienophiles to afford novel octahdroquinolines. The process is highly stereoselective and provides heterocyclic products containing synthetically useful functionality.     

Synthesis and synthetic utility of 1-acyl-2-alkyl-4-trimethylstannyl-1,2-dihydropyridines

1-Acyl-2-alkyl-1,2-dihydropyridines were prepared from 4-trimethylstannylpyridine and Grignard reagents. This methodology was utilized in the synthesis of N-methyl-2-azatricyclo[5.3.1.0]undecane.     

A one-step conversion of esters to secondary alcohols with LiBH4-RMgX

A one-pot synthesis of secondary alcohols from esters and LiBH₄-RMgX is described.     

Effects of 3-amino-1,2,4-triazole on the inhibition of copper corrosion in acidic chloride solutions

Effects of 3-amino-1,2,4-triazole (ATA) on the inhibition of copper corrosion in 0.5 M HCl solutions have been studied using gravimetric, electrochemical, and Raman spectroscopy investigations. Weight-loss measurements after varied immersion periods revealed that the dissolution rate of copper decreased to a minimum, while the inhibition efficiency (zeta%) and consequently the degree of surface coverage (theta) increased with the presence of ATA and the increase of its concentration. Potentiodynamic polarization, chronoamperometric, and electrochemical impedance spectroscopy (EIS) measurements after 0, 24, and 48 h immersion of the copper electrode in the test solutions showed that the presence of ATA molecules significantly decreased cathodic, anodic, and corrosion (jcorr) currents and corrosion rates (Rcorr) and greatly increased polarization resistance (Rp), zeta%, and theta; this effect was increased on increasing the ATA content in the solution. Raman spectroscopy confirmed that ATA molecules strongly adsorbed onto the copper surface, blocking its active sites and preventing it from being corroded easily.     

Analysis of the composition of the passive film on iron under pitting conditions in 0.05 M NaOH/NaCl using Raman microscopy in situ with anodic polarisation and MCR‐ALS

The composition of the surface film formed on pure iron was investigated in a solution of 0.05 M NaOH and 0.05 M NaCl. Raman spectra of the film were recorded in situ during anodic polarisation over the passive region after addition of the NaCl to the electrolyte, under conditions of preresonance enhancement using excitation at 636.4 nm. Multivariate curve resolution with alternating least squares analysis was applied to the spectra to measure the relative amounts of different iron oxide and oxyhydroxides in the film at different potentials. The water content was also determined in this way from Raman spectra recorded using excitation at 514.5 nm. It was found that the composition of the film and the amount of incorporated water were influenced by the applied anodic potential. The results show that stable pitting can occur when the composition changes from the primary constituents β‐FeOOH and Green Complex (a hydrated, amorphous magnetite) with smaller amounts of γ‐Fe₂O₃ and γ‐FeOOH, to δ‐FeOOH and Green Complex, simultaneously with a reduction in water content. These changes result in conditions that favour the rate of localised breakdown of the film by Cl⁻ ions over the rate of repassivation by water in the passive film. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis of 4-alkyl-3-pyridinols from 3-benzyloxypyridine

The addition of Grignard reagents to the 1-phenoxycarbonyl salt of 3-benzyloxypyridine and a catalytic amount of cuprous iodide afforded 4-alkyl-3-benzyloxy-1-phenoxycarbonyl-1,4-dihydropyridines in good yield. The crude dihydropyridines were aromatized with o-chloranil to give 4-alkyl-3-benzyloxypyridines, which were debenzylated with hydrogen and 10% palladium on carbon to provide 4-alkyl-3-pyridinols.