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...
Major and minor minerals have been separated from
three L-6 chondritic meteorites (Alfianello, Colby (Wisconsin),
and Leedey). Olivine, hypersthene, diopside, feldspar,
troilite, chromite, phosphate minerals, and metallic
minerals were analyzed for major, minor and trace elements
using instrumental neutron activation analysis and radiochemical
neutron activation analysis techniques. Concentrations
df the...
In order to examine some possible tyrosyl interactions, poly-tyrosyl lysozyme and poly-O-methyltyrosyl lysozyme were prepared and their solubilities were compared. Both derivatives exhibited
similar pH dependent solubilities, showing a minimum solubility at
about pH 8. Their solubilities varied with temperature, having a
positive enthalpy of solution. The effect of a...
Polypeptidyl derivatives of bovine pancreatic ribonuclease
(RNase) containing two or three tyrosine chains
with an average of two to three residues per chain have
been prepared. The effects of various perturbants such as
neutral salts, ethanol, urea and guanidine hydrochloride
on the thermal transition of the derivatives have been
studied....
Synthesis and discovery lies at the core of every field in chemistry. The investigation of the structure-property relationships in compounds known or new is the fundamental purpose of solid state chemistry. Mixing related solid state compounds to form solid solutions can lead to exciting new and/or unexpected properties. Layered compounds...
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...
Both oxy-Cope and siloxy-Cope rearrangements involve
(1, 3) and (3, 3) sigrnatropic shifts. Both the concerted mechanism,
and the stepwise mechanism via a diradical intermediate are possible.
In a cyclic system such as cis-l-vinylcyclooct-3-en-l-ol, the thermal
rearrangement takes place preferably through a diradical intermediate.
At high temperature, the reaction also...
The rate of the C¹⁴0₂ release from glucose, specifically labeled
with C¹⁴ at 1, 2, 3+4, and positions, was used to study the relative
participation of pathways of glucose catabolism in red beet slices.
Evidence was obtained which indicated that in mature red beets glucose
was catabolized mainly via glycolysis-tricarboxylic...
The potassium salts of certain 1-vinylcycloalk-3-en-l-ols have
been found to undergo sigmatropic ring expansion rearrangements in
HMPA. Preliminary investigations of several benzo-substituted medium
ring systems were undertaken in order to determine which of these
was best suited for further study. A synthetic sequence leading to
the formation of 5-methy1-6-viny1-7,8,9,10-tetrahydro-6-benzocyclo-octenol,
which...
To determine the impact of emerging environmental contaminants on human and environmental health, quantitative analytical methods are required. Analysis of emerging contaminants is hampered by their widely varying physical-chemical properties. Therefore quantitative analytical methods must be developed to determine the behavior of emerging contaminants in environmental systems.
A quantitative analytical...
Two labelled arginines, DL-[2,3,3,-²H₃]arginine, 8,
and DL-[ ¹³C, 2-¹⁵N]arginine, 9, were synthesized. These
were fed to cultures of Streptomyces griseochromogenes in
order to probe the mechanism of the apparent arginine-2,3-
aminomutase reaction occurring in biosynthesis of blasticidin
S, 1. In previous studies of the enzymes lysine-2,3-
aminomutase and tyrosine-2,3-aminomutase different...
Part 1
The pyrolysis of cis-1-trimethylsiloxy-1-cyclopr opyl-3-cyclononene in the temperature range 285-350° is described. Instead
of siloxy-Cope rearrangement, undesired desiloxylation took place.
Part 2
Gas-phase pyrolytic rearrangement of 2-phenyl-1-trimethylsiloxy-1-vinylcyclononane was investigated in a static system
in the temperature range 213-330°. It was discovered that
three major products resulted: cis- and...
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...