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Structural
Studies of Racemates and Quasiracemates:
Chloro,Bromo, and Methyl Adducts of
2-Phenoxypropionic Acid
2008
Aaron M. Lineberry, Ellis T.
Benjamin, Raymond E. Davis, W. Scott Kassel,
Kraig A. Wheeler. Structural Studies of
Racemates and Quasiracemates: Chloro, Bromo, and
Methyl Adducts of 2-Phenoxypropionic Acid.
Crystal Growth &
Design. 2008,
8(2),
612–619.
Abstract:
Quasiracemic compounds derived
from the enantiopure Cl, Br, and CH3
analogues of 2-phenoxypropanoic acid crystallize
to give approximate centrosymmetry
supramolecular assemblies. Each quasiracemate
forms the anticipated heterodimers via O-H· · ·O
carboxyl interactions that lead to two distinct
packing motifs in space group P21 with
Z′ = 2 (Cl/Br and Br/CH3) or 8 (Cl/CH3
and Br/CH3).
The Z =
2 quasiracemates are isostructural with (rac)-Cl
and (rac)-Br, while the Z' = 8
structures form molecular patterns that resemble
the packing preferences of (rac)-CH3. The
Br/CH3 quasiracemate was retrieved as
concomitant polymorphs.
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The Synthesis of
Unsubstituted Cyclic Imides Using Hydroxylamine
under Microwave Irradiation.
2008
Ellis Benjamin and Yousef Hijji. The
Synthesis of Unsubstituted Cyclic Imides Using
Hydroxylamine under Microwave Irradiation.
Molecules.
2008,
13, 157-169.
Abstract:
Unsubstituted cyclic imides were
synthesized from a series of cyclic anhydrides,
hydroxylamine hydrochloride (NH2OH·HCl),
and 4-N,N-dimethylamino-pyridine (DMAP,
base catalyst) under microwave irradiation in
monomode and multimode microwaves. This novel
microwave synthesis produced high yields of the
unsubstituted cyclic imides for both the
monomode (61 - 81%) and multimode (84 - 97%)
microwaves.
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Mathematical
Models for Conventional and Microwave Thermal
Deactivation of Enterococcus faecalis,
Staphylococcus aureus and Escherichia coli.
2007
Earl Benjamin, Aron Renzik, Ellis
Benjamin, Arthur L. Williams. Mathematical
Models for Conventional and Microwave Thermal
Deactivation of Enterococcus faecalis,
Staphylococcus aureus and Escherichia coli.
Cell Mol. Biol. 2007,
53(3),
42-48.
Abstract:
Temperature
dependencies of survival fecal coliforms such as
Enterococcus faecalis, Staphylococcus aureus and
Escherichia coli in water were investigated
between 25 - 65 °C. Measured dependencies had
"bell" shaped form with maximum bacterial
viability at 35 - 45 °C. The rates of growth and
decay of bacterial viability depend on specific
forms of bacteria. At temperatures of 60 - 65 °C
the number of viable bacteria decreased in one
hundred times in comparison with the maximum
value. Similar "bell" shape forms were found for
dependencies between bacterial viability and
time of microwave (dielectric) heating of
water. The dependencies had maximum value at 1 -
2 min of microwave heating. Then, the number of
viable bacteria decreased, and at 4 - 5 min of
microwave heating, became insignificantly small.
The proposed mathematical models for
conventional and microwave heating took into
account "growth" and "death" factors of
bacteria, and had forms of second degree
polynomial functions. The results showed good
relationships (with coefficient correlation
0.84 - 0.99) between the proposed mathematical
models and experimental data for both
conventional and microwave heating.
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Mathematical
Model of Manganese Ion Catalyzed Microwave
Deactivation of Enterococcus faecalis,
Staphylococcus aureus and Escherichia coli.
2007
Earl Benjamin, Aron Renzik, Ellis
Benjamin, Arthur L. Williams. Mathematical
Model of Manganese Ion Catalyzed Microwave
Deactivation of Enterococcus faecalis,
Staphylococcus aureus, and Escherichia coli.
Cell Mol. Biol. 2007,
53(3),
49-54.
Abstract:
Enterococcus faecalis,
Staphylococcus aureus and Escherichia coli
survival was investigated using microwave
irradiation (power 130 W) both in a water
control and in the presence of a 1 µM manganese
ion solution. Measured survival dependencies had
"bell' shape form with maximum bacterial
viability between 1 - 2 min of microwave
heating. Additional heating revealed bacteria
survival decreasing up to 3 min of microwave
heating when viability became insignificantly
small. The total deactivation time of bacteria
in the presence of manganese ions was
significantly smaller then that of bacteria
irradiated in the microwave without manganese
ions present (4 -5 min). One possible
explanation for the rapid reduction of bacterial
survival during microwave irradiation in the
presence of manganese ions is that increasing
manganese ion penetration into bacteria along
with microwave irradiation related to an
increase of kinetic energy of ions, and damaging
of bacteria by metal ions. The proposed
mathematical model for microwave heating took
into account "growth" and "death" factors of
bacteria. It assumes that rates of bacterial
growth and decay are linear functions of water
temperature, and rate of bacterial decay that
relates with metal concentration into water is
also linear, which influenced the differential
equation for the dependence between number of
survival bacteria and temperature water. By
using proportionality between the time of
microwave heating and water temperature we
derived the differential equation, between
bacterial viability and time of microwave
irradiation which was used as mathematical model
for microwave heating in the presence of metal
ions. This model had forms of second-degree
polynomial functions. We received good
relationships (with coefficient of correlation
0.92 - 0.99) between proposed mathematical model
and experimental data for all bacterial
deactivation.
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1-Methoxy-pyrrolidine-2,5-dione
2007
Ray
J. Butcher, Yousef M. Hijji, Ellis Benjamin.
1-Methoxy-pyrrolidine-2,5-dione
Acta Cryst. 2007,
E63,
o1502-o1503.
Abstract:
The title
compound, C5H7NO3,
was synthesized by microwave methods. The five-membered
pyrrolidine-2,5-dione ring is planar. There is
extensive C—H...O hydrogen bonding.
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3-Aminocyclopent-2-en-1-one
2007
Ray J. Butcher, Yousef M. Hijji, Ellis
Benjamin. 3-Aminocyclopent-2-en-1-one
Acta Cryst.
2007,
E63, o610–o612.
Abstract:
The title
compound, C5H7NO, was
synthesized by the reaction of
1,3-cyclopentanedione with ammonium acetate
under microwave conditions in 81% yield. The
crystal packing is determined by intermolecular
N—H...O and C—H...O
hydrogen bonds.
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Efficient
Microwave Assisted Syntheses of Unsubstituted Cyclic Imides.
2006
Yousef M. Hijji, Ellis Benjamin.
Efficient Microwave Assisted Syntheses of
Unsubstituted Cyclic Imides.
Heterocycles
2006,
68(11), p2259-2267.
Abstract:
A number of
cyclic imides were synthesized from cyclic
anhydrides using ammonium chloride (NH4Cl), and
4-N,N-dimethylaminopyridine (DMAP) or with
ammonium acetate (NH4OAc) under microwave
irradiation in both a mono-mode and a
conventional microwave. Several substituted succinic anhydrides used as reactants were
synthesized efficiently by Diels-Alder reactions
of maleic anhydride with 1,3-cyclohexadienes in
63-82% for the mono-mode and 72-92% in the
conventional microwave ovens. Cyclic imides were
synthesized with yields from 50 – 98%.
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cis-3-Azabicyclo[3.2.0]heptane-2,4-dione
2006
Raymond J. Butcher, Yousef M. Hijji,
Ellis Benjamin,
cis-3-Azabicyclo[3.2.0]heptane-2,4-dione.
Acta Cryst.
2006,
E62,
o1266-o1268.
Abstract:
The title
compound, C6H7NO2,
was synthesized from
cis-1,2-cyclobutanedicarboxylic anhydride by
reaction with ammonium acetate under microwave
conditions. The crystal structure of the
compound shows that the cyclobutane ring is
planar with angles ranging from 89.64 (12) to
90.37 (12). The
cis-3-azabicyclo[3.2.0]heptane-2,4-dione
molecules are linked into a chain formation
through hydrogen N—H...O=C bonds. Parallel packing
is seen between two cyclobutane rings related by
inversion symmetry.
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Efficient
Synthesis of Enaminones
and Cyclic Imides Using Ammonium Acetate Under
Microwave Conditions.
2005
Yousef Hijji, Ellis Benjamin,
Melvin Bolden. Efficient Synthesis of Enaminones
and Cyclic Imides Using Ammonium Acetate Under
Microwave Conditions.
Proceedings of
the 39th Annual International Microwave Power
Institute 2005, p125-128.
Seattle, Washington. (July 2005)
Abstract:
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Microwave
Assisted Efficient Conversion of Anhydrides to
Cyclic Imides and N-Methoxy
Imides.
2004
Yousef M. Hijji, Ellis Benjamin.
Microwave Assisted Efficient Conversion of
Anhydrides to Cyclic Imides and N-Methoxy
Imides. The
5th, 6th, 7th, and 8th International Electronic
Conferences on Synthetic Organic Chemistry
2004, p1084-1091. Editor(s): Seijas,
Julio A.
Abstract:
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