1,416 research outputs found
Aziridine-Metathesis based Approaches to Alkaloid Synthesis
The aim of the project is to synthesise (-)-morphine utilising aziridine and metathesischemistry. The thesis is divided into three chapters.Chapter 1 provides brief reviews on the subjects of total synthesis of morphine; ringrearrangementmetathesis (RRM) and regioselective ring-opening of aziridines.Chapter 2 focuses on the research findings in the past three years. Two routes, A and B,were investigated in attempts to synthesise morphine (Scheme 1). In route A, sulfonylcyclopentene II was prepared from ring-closing metathesis of a diene precursor, whichwas synthesised from lithiated cinnamylsulfone and butadiene monoxide. Subsequently,RRM reactions of several [alpha]-SO2Ph allyl derivatives of II were investigated and someinteresting results were obtained. The synthesis of 2,3-trans vinylaziridine III wasachieved in seven steps beginning with a Grignard reaction of (4-methoxyphenyl)magnesium bromide with butadiene monoxide. Subsequently, somehighly regioselective ring-opening reactions of III with sulfur-stabilised anionicnucleophiles were achieved. However, in an attempt to synthesise compound I from IIand III, no reaction was observed. This led to the investigation of route B, in which fivemethods for the synthesis of compound IV were investigated. The practical approachdeployed a novel Al-mediated substitution of the 4-tosyl group of the tosyltetrahydropyridine counterpart of IV, prepared from V and III, with a phenylthio group.Chapter 3 provides the experimental details and characterisation data.Imperial Users onl
Aziridine–Metathesis based Approaches to Alkaloid Synthesis
The aim of the project is to synthesise (–)-morphine utilising aziridine and metathesis
chemistry. The thesis is divided into three chapters.
Chapter 1 provides brief reviews on the subjects of total synthesis of morphine; ringrearrangement
metathesis (RRM) and regioselective ring-opening of aziridines.
Chapter 2 focuses on the research findings in the past three years. Two routes, A and B,
were investigated in attempts to synthesise morphine (Scheme 1). In route A, sulfonyl
cyclopentene II was prepared from ring-closing metathesis of a diene precursor, which
was synthesised from lithiated cinnamylsulfone and butadiene monoxide. Subsequently,
RRM reactions of several α-SO2Ph allyl derivatives of II were investigated and some
interesting results were obtained. The synthesis of 2,3-trans vinylaziridine III was
achieved in seven steps beginning with a Grignard reaction of (4-
methoxyphenyl)magnesium bromide with butadiene monoxide. Subsequently, some
highly regioselective ring-opening reactions of III with sulfur-stabilised anionic
nucleophiles were achieved. However, in an attempt to synthesise compound I from II
and III, no reaction was observed. This led to the investigation of route B, in which five
methods for the synthesis of compound IV were investigated. The practical approach
deployed a novel Al-mediated substitution of the 4-tosyl group of the tosyl
tetrahydropyridine counterpart of IV, prepared from V and III, with a phenylthio group.
Chapter 3 provides the experimental details and characterisation data
A Vertical Channel Model of Molecular Communication based on Alcohol Molecules
The study of Molecular Communication(MC) is more and more prevalence, and
channel model of MC plays an important role in the MC System. Since different
propagation environment and modulation techniques produce different channel
model, most of the research about MC are in horizontal direction,but in nature
the communications between nano machines are in short range and some of the
information transportation are in the vertical direction, such as transpiration
of plants, biological pump in ocean, and blood transportation from heart to
brain. Therefore, this paper we propose a vertical channel model which
nano-machines communicate with each other in the vertical direction based on
pure diffusion. We first propose a vertical molecular communication model, we
mainly considered the gravity as the factor, though the channel model is also
affected by other main factors, such as the flow of the medium, the distance
between the transmitter and the receiver, the delay or sensitivity of the
transmitter and the receiver. Secondly, we set up a test-bed for this vertical
channel model, in order to verify the difference between the theory result and
the experiment data. At last, we use the data we get from the experiment and
the non-linear least squares method to get the parameters to make our channel
model more accurate.Comment: 5 pages,7 figures, Accepted for presentation at BICT 2015 Special
Track on Molecular Communication and Networking (MCN). arXiv admin note: text
overlap with arXiv:1311.6208 by other author
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