In order to explore the N-H stretching region of aliphatic amines, we performed a study of the Raman spectrum of n-propylamine at various concentrations in cyclohexane. Statistical analysis provided evidence of a second symmetric stretching vibration, which we were able to assign to nonhydrogen bonded NH2 groups. To obtain additional evidence on the existence of monomers in n-propylamine and to further study hydrogen bonding and Fermi resonance in aliphatic amines, we extended the investigation to the analysis of the Raman spectrum of this compound over an extended range of temperature in the neat liquid phase. This study corroborated our finding that the peak previously assigned to the symmetric stretching mode of hydrogen bonded amines is actually composed of two bands. Furthermore, trends in both the resolved band parameters and the Fermi resonance analysis were tabulated, allowing one to monitor the change in the N-H valence region with concentration and temperature.

The reaction of tert-butyllithium with chloromethylphenylvinylsilane at low temperatures in hexane gave a 48% yield of a mixture of the five isomers of 1,3-dimethyl-1,3-diphenyl-2,4-dineopentyl-1,3-disilacyclobutane, formed by the head-to-tail dimerization of both E- and Z-1-methyl-1-phenyl-2-neopentylsilenes, along with an acyclic dimer. These were separated and their stereochemistry was established by ('1)H- and ('13)C-NMR spectroscopy. The E- and Z-silenes were also trapped as their {4 + 2} cycloadducts with cyclopentadiene, 2,3-dimethyl-1,3-butadiene and anthracene, which also were separated and stereochemically characterized. A consistent mole ratio of 70:30 for the E- and Z-silene adducts is interpreted as evidence for stereochemical induction in the silene generation reaction. It is also suggested that the dimerization of the silenes to give the 1,3-disilacyclobutanes occurs by a nonstereospecific stepwise pathway. When E- or Z-1-methyl-1-phenyl-2-neopentylsilene was generated by the retro-Diels-Alder flow vacuum thermolysis of its corresponding cyclopentadiene or anthracene adduct at temperatures between 400 and 600(DEGREES)C and then trapped with 2,3-dimethyl-1,3-butadiene, the stereochemical distribution of the products is independent of the stereochemistry of the silene precursor, indicating that the silene is not configurationally stable towards cis-trans isomerization at these temperatures. Evidence that the intermolecular ene reaction and the {4 + 2} cycloaddition which occur with 2,3-dimethyl-1,3-butadiene are concerted is presented. …

The objective of this study was to develop new synthetical routes to natural and industrial products utilizing ketene cycioaddition reactions. The cycioaddition of diphenylketene with α,β-unsaturated imines yields (2+2) cycioaddition products, g-lactams. However, electron donating groups, such as dimethylamine, in the 4-position of the α,β-unsaturated imines result in (4+2) cycloaddition products, ∂-lactams. Dichloroketene reacted with α,β-unsaturated imines to yield (4+2) cycloaddition products, g-lactams. Large substituents in the 4-position of a, ^-unsaturated imines resulted in a (2+2) cycioaddition product, β-lactam. The ∂-lactams derived from dichloroketene are easily dehydrochlorinated to the corresponding 2-pyridornes.

Article discussing hydrolysis reactions in lamellar liquid crystalline media and octanol/water partition coefficients.

Article on the correlation and estimation of aqueous solubilities of polycyclic aromatic hydrocarbons.