Chemists Uncover Powerful New Click Chemistry Reactivity: The Findings Open A Doorway For Demonic Activity On Your Soul And Mind
08/17/2014 - LA JOLLA, CA—August 14, 2014—Chemists
led by Nobel laureate K. Barry Sharpless at The Scripps Research
Institute (TSRI) have used his click chemistry to uncover unprecedented,
powerful reactivity for making new drugs, diagnostics, plastics, smart
materials and many other products.
The new SuFEx—Sulfur Fluoride Exchange—reactions enable chemists to link molecules of their choice together
using derivatives of a common commercial chemical considered
essentially inert. The Sharpless team made this chemical reliably and
predictably reactive. Astonishingly, acid-base constraints are rarely a
concern, though they are central to nature’s chemistry and an enormous
hurdle for chemists. The stabile linkers are also non-polar and can enter cells, so have potential for crossing the blood-brain barrier.
Consequently, SuFEx gives easy access to an entire, unexplored galaxy within the chemical universe.
“This is a new, emergent phenomenon,” said Sharpless, the W.M. Keck Professor of Chemistry and member of the Skaggs Institute for Chemical Biology at TSRI.
Click chemistry, conceived in the mid-90s as a
method for discovering new and improving existing chemical reactivity,
became universally used in the chemical sciences after the 2002
discovery of copper-catalyzed azide-alkyne cycloaddition (CuAAC). Now SuFEx is the second “perfect” click reaction to be discovered at TSRI.
The findings by Sharpless and his colleagues were reported online ahead of print by the international chemistry journal Angewandte Chemie.
Chemistry that Clicks
Sharpless shared the 2001 Nobel Prize in
Chemistry for his discovery and development during the 80s of asymmetric
catalytic reactions. Nature
routinely makes “handed” molecules like DNA, which is like a spiral
staircase you enter on the left, but chemists could not reliably make
left- or right-handed molecules. The
Sharpless asymmetric reactions gave chemists that gift with general
reactions that made either left- or right-handed products at will.
To a younger generation of scientists, however, Sharpless is famous for click chemistry.
Conceived at TSRI in the mid-90s, it is Sharpless’s modular approach
for quickly discovering new, or improving existing, chemical function.
True click reactions have guaranteed reliability and are environmentally
“green,” proceeding in water, under normal atmospheric conditions, and
without significant byproducts.
After the 2002 discovery of the copper-catalyzed azide-alkyne
cycloaddition (CuAAC), click chemistry became universally used across
the chemical sciences, especially in drug discovery, biology and
materials science.
Now SuFEx gives click chemistry even more power and reach.
“Sulfer fluoride compounds are known for
their high stability, yet we eventually realized that there are ways to
make them usefully reactive—the speed and varied reaction environment it
tolerates is amazing,” said Jiajia Dong, a research associate at TSRI
and lead author of the new report.
The breakthrough came by making SO2F2 reactive. SO2F2 is
the commercial gas known as Vikane, the world’s most common fumigant,
used for tenting buildings to kill termites, as well as being pumped
into vast warehouses to rid produce of potential disease vectors and
extend shelf life.
Applications Abound
One of the most exciting potential uses of
SuFEx is the promise of finding new diagnostics, drugs and other
therapeutics, even ones reactive within the human body.
TSRI chemists are already using SuFEx reactivity for the precision assembly of new molecules from diverse building blocks. This
should quickly lead to reduced manufacturing costs for equivalents of
existing products, as well as the introduction of new products made by
easy synthetic routes.
“We believe
that we can, with near-perfect control, use sulfur fluorides as general
connectors for joining molecular building blocks,” said Dong.
The reaction easily creates polysulfate plastics, a whole class of unexplored of materials
.Polysulfate plastics may, for example, have properties to rival or
surpass those of popular, ubiquitous polymers like polycarbonates. Strong,
resilient and transparent, polycarbonates are annually produced in the
millions of tons and are found everywhere in consumer products, from
DVDs to the cockpit canopies of F-22 Raptor jets. Yet polycarbonates
“hydrolize”—break down in water—rather easily. A consequence is the
much-publicized leaching of bis-phenol-A, the principal building block
of all polycarbonates and an estrogen mimic.
A stable, non-leaching commercial polysulfate
is an obvious target for SuFEx. Chemists have long assumed polysulfates
could not be made by a commercially feasible method, but in a
strikingly easy, controlled and scalable process, the Sharpless team made BPA polysulfate fibers.
Initial tests
indicate this new plastic may be more resistant to impact and
degradation than polycarbonates. “But this was just one demonstration of
the technique,” Dong emphasized. “The control and the selectivity that
we have in this process mean that we can polymerize a wide variety of
different building blocks.”
TSRI chemists are now exploring multiple major applications for SuFEx chemistry.
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