The thermolysis of trans-1 -trimethylsiloxy- 1-vinylcyclotridec-
3-ene (VI-OTMS) led to the formation of two major products: 4-vinylcyclotridecanone
(VII) and cyclopentadec-5-en-l-one (VIII) after
hydrolysis. Ketone VII is produced by a concerted [3, 3] sigmatropic
shift, while ketone VIII is formed by a [1, 3] sigmatropic shift with
a concerted or diradical...
Ambient high-volume (hi-vol) air samples were collected between March 15th and May 30th 2002, at Cheeka Peak Observatory (CPO), located on the tip of the Olympic Peninsula, Washington State. This sampling campaign was in conjunction with the 2002 Inter-Continental Transport and Chemical Transformation (ITCT 2K2) Campaign and the Photochemical Ozone...
Atmospheric fine particulate matter (PM2.5) has been linked to the death of 7 million people per year around the planet. The organic portion of PM2.5 is responsible for increases in oxidative stress, inflammation, mutation and carcinogenesis. Anthropogenic activity releases more organic material into the atmosphere, and has increased the amount...
Part I
The pyrolysis of cis- and trans- 1, 2-divinyl-1- trimethylsiloxy -
cyclohexane, II- and III-TMS, under the same conditions as the
pyrolysis of cis-l-vinyl -1-trimethylsiloxycyclooct-3-ene, I-TMS,
confirms that a sequence of concerted reactions for the rearrangement
of II- and III-TMS to trans-l-trimethylsiloxycyclodec-3-ene,
IV-TMS, is a viable pathway in the...
During a study of the abnormal dienone-phenol rearrangement
discovered by Marvell and Geiszler, Imel (1960) found that 4-oxo-3,3-dimethyl-3,4-dihydrophenanthrene rearranged slowly to a phenol
which was tentatively identified as 3,4-dimethyl-l-phenanthrol;
further evidence to support this assignment was deemed essential.
The recent work by Mallory on the photochemical conversion of
stilbenes to...
The loss of all deuterium labels from previous feedings of [2-²H]-,
[3,3-²H₂]-, and [2,3,3-²H₃]arginines had indicated the possible intermediacy
of β-hydroxy- and β-ketoarginine (30 and 31, respectively) in the
biosynthesis of the streptolidine portion of streptothricin F (la).
In order to confirm or refute this evidence, D,L-[2,3,3,5,5-²H₅]-
arginine (32) was...
The potassium salts of a series of 1-vinylcycloalk-3-en-l-ols were found to undergo ring expanding [1, 3]-sigmatropic shifts at 25° when dissolved in hexamethylphosphoramide (HMPA) or 1, 2-dimethoxyethane (DME) with 18-crown-6. The yields and reaction rates were compared with those of the corresponding Siloxy-Cope ring expansions. These anionic cases showed about...
The effect of the conjugation with cyclopropyl rings
on the activation parameters for the formation of
carbenes from the corresponding diazo compounds was
investigated using diisopropylcarbene (46), cyclopropyl-isopropylcarbene
(47), and dicyclopropylcarbene (48).
Each of these three carbenes was generated by the
thermolysis of the parent benzenesulfonylhydrazone
potassium salts using DMSO...
The photodebromination of selected bromoarenes has been studied at 300 nm
to determine the the possible mechanistic pathways leading to product.
Irradiation of 4-bromobiphenyl (BpBr) at this wavelength leads to the product
biphenyl. The quantum yield of intersystem crossing (0.98) and quenching
studies with cis-1 ,3-pentadiene suggest that the reaction...
The relative rates of hydrogen abstraction from a series of 13
arylmethanes by the trichloromethyl radical were determined at 70°.
The attacking radical was generated from bromotrichloromethane us
ing benzoyl peroxide as the initiator. The solvent was benzenebromotrichloromethane.
An excellent correlation, with a coefficient
of 0.977, was obtained when the...
The relative rates of hydrogen atom abstraction from a series of
13 homoaryl and heteroarylmethanes by t-butoxy radical were determined at 70°C. The attacking radical was photochemically generated
from di-t-butyl peroxide. A relatively small range of relative rates
(factor of seven) has been found among the compounds studied. The
relative...
Six polycyclic aliphatic hydrocarbons were reacted with the
trichloromethyl radical photolytically generated from bromotrichloromethane
at 40°. Relative rates of reaction were correlated
with a computer analysis of the change in strain energy in going
from the ground state to the intermediate. A good correlation between
the log of the relative...
The 3-cyclohexenyl carbinyl carbene species was formed by the
thermal decomposition of the p-toluenesulfonylhydrazone sodium
salt and by oxidation of the hydrazone. Several oxidizing agents
were studied. The products were investigated under aprotic and
protic conditions and at various temperatures. The diazocompound
was formed as an intermediate and found to...
The photolysis of the aqueous thymine system has been investigated
at 214 nm, 229 nm and 254 nm at room temperature. Products
of photolysis have been identified as hydrogen peroxide, 6-hydroxy-5-
hydroperoxy thymine and tentatively 5-hydroxy-6-hydroperoxy thymine.
These together with thymine loss, were determined quantitatively
under a variety of conditions....