Parekh, Hemal (2011) Evolvable process design. PhD thesis, University of Warwick.

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Abstract

The aim of this project lied in the development of an Evolvable Process
Design (EPD) reactor platform such that 'evolved' chemical reactions could be
investigated for the first time. The development of this 'machine' would allow us to
take small organic / inorganic building blocks and use them to prepare any
theoretical compound with any theoretical property that is determined by the
'machine'. One of the essential components required were building blocks that can
reversibly react under various conditions until a product with a desired property has
been evolved. As we were developing a proof-of-principle EPD, we at Warwick
concentrated on synthesizing a library of uniquely coloured imine products to prove
a desired coloured imine could be evolved in the 'machine'.
For this we first required a suitable analytical method that could accurately
detect multiple components in a mixture (three aldehydes, three amines resulting in
nine imine products) so we could understand the reaction before placing into the
'machine'. In chapter 2, we demonstrated that 19F NMR spectroscopy was sufficient
to monitor in real time the equilibrium of a 3 x 3 matrix of fluorinated amine +
aldehyde building blocks (nine imines). We also demonstrated that the system of our
study was under a dynamic equilibrium and that by altering the acid or base
concentrations, we can affect the dynamics of the reaction and monitor it
quantitatively.
In chapter 3, we synthesized a library of highly conjugated aromatic imines
from fluorinated aldehydes and non-fluorinated amines. These imines possessed
unique UV / Vis profiles (and unique 19F NMR data) therefore could be monitored in
our 'machine' equipped with a UV / Vis sensor.
In chapter 4, a reaction was ready to be trailed on the 'machine' as previously
synthesized in chapter three but no such 'machine' had been developed by our
collaborators and therefore we created our own mini-flow system to test in situ UV /
Vis absorbance measurements of our library of imines.
In chapter 5 we focused on synthesizing imine ligands for metal mediated
atom transfer radical cyclization reactions (ATRC) (extensively studied by the Clark
group) as this 'machine' was still under development by our collaborators. We knew
that once the 'machine' was developed, we could tweak the system in a way which
would allow us to develop optimised imine catalysts for ATRC reactions.
In chapter 6 we demonstrated KBH4 to be the most efficient reducing agent
for copper mediated AGET / ARGET – ATRC and by increasing the concentration
of the reaction mixtures we significantly improved the efficiency of copper mediated
AGET–ATRC of previously investigated reactions by the Clark group. We also
demonstrated copper mediated AGET-ATRC in water at good conversions using
ultrasound, replacing a toxic solvent and may now be considered as 'green'
chemistry.
In chapter 7, we were able to demonstrate an alternative procedure to
oxindoles via copper meditated cyclisation reaction. In the presence of 1.1 equiv. of
CuBr / TPA in methanol at 50 oC we were able to show 100% conversions of
substrates 2-Bromo-N-butyl-2-methyl-N-(p-tolyl)propanamide and 2-Bromo-Nbutyl-
2-methyl-N-(m-tolyl)propanamide. We then performed a series of reactions to
reduce the transition metal and ligand loadings by using borohydride reducing agents
but unfortunately, these reactions were not that efficient.

Item Type:	Thesis or Dissertation (PhD)
Subjects:	Q Science > QD Chemistry
Library of Congress Subject Headings (LCSH):	Chemical reactions, Imines -- Synthesis
Official Date:	September 2011
Dates:	Date Event September 2011 Submitted
Institution:	University of Warwick
Theses Department:	Department of Chemistry
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Clark, Andrew J.
Extent:	xiii, 286 leaves : ill.
Language:	eng
URI:	http://wrap.warwick.ac.uk/id/eprint/46924

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