The electrophilic addition of halogens is one of the most characteristic reactions of unsaturated hydrocarbons. In organic textbooks the cyclic three-membered halonium ions are postulated as key intermediates to account for the observed stereochemistry in halogenation reactions of alkenes. Strong experimental evidence supporting the mechanism comes from the reactions of hindered alkenes, which ...

Cyclic peptides have attracted increasing attention in recent years due to their ability to inhibit protein-protein interactions. Current strategies to prepare cyclic peptides often rely on functional amino acid side chains or the incorporation of unnatural amino acids, thus limiting their structural diversity. Here, we describe the development of a highly versatile peptide macrocyclization str...

The structural relation of several potent carcinogenic hydrocarbons to cyclopentenophenanthrene, which forms the cyclic portion of cholesterol, bile acids, and steroid hormones, has given rise in recent years to various speculations concerning the role which cholesterol and other steroid derivatives may play in tumor metabolism. However, there are also numerous carcinogenic aromatic hydrocarbon...

Releases of hydrocarbons from oil spills have large environmental impacts in both the ocean and atmosphere. Oil evaporation is not simply a mechanism of mass loss from the ocean, as it also causes production of atmospheric pollutants. Monitoring atmospheric emissions from oil spills must include a broad range of volatile organic compounds (VOC), including intermediate-volatile and semivolatile ...

As the basis and preliminary work of future experimental study on PAHs formation under high temperature, theoretical computations on the intramolecular rearrangement reactions of sylvestrene (1-methyl-3-vinylcyclohexene) and 1,4-dimethyl-4-vinylcyclohexene are conducted and reveal that they may be transformed to themselves. The conversion between Dipentene and 2,4-dimethyl-4-vinylcyclohexen...

The glomerular sheet of the olfactory bulb (OB) forms odorant receptor maps that are parceled into zones. We previously reported the molecular receptive range (MRR) property of individual glomeruli in the dorsal zone (zone 1) of the OB and showed that polar functional groups play a major role in activating glomeruli in this zone. However, the MRR property of glomeruli in zones 2-4 is not well u...

Ab initio quantum mechanical calculations have been performed to establish the potentials for alkyl-substituted polyhedral oligomeric silsesquioxane (POSS) monomers RxH8-x(SiO1.5)8. More specifically, we have examined the unsubstituted POSS (SiO1.5H)8 cage as well as linear and cyclic alkyl-substituted cages where one of the terminating hydrogen atoms is replaced by a hydrocarbon group, that is...

In this work, we study the reaction mechanism of the tricarbonylchromium complex haptotropic rearrangement between two six-membered rings arranged like in naphthalene of four polycyclic aromatic hydrocarbons (PAHs). It has been found that the reaction mechanism of this haptotropic migration can either occur in a single step or stepwise depending on the interaction between the orbitals of the Cr...

VUV absorbance and index of refraction data for a series of linear and cyclic alkanes have been collected in order to understand the relationship between the electronic excitation wavelength (or absorbance edge), index of refraction, and molecular structure. The absorbance edge and index for a homologous series of both linear and cyclic alkanes increase with increasing carbon number. The optica...