Development of novel heterocyclic compounds as vascular targeting agents

In chapter one the biology of cancer is introduced along with a brief history of drug treatment and the status quo of cancer therapeutics. This includes a general overview of cancer prevalence, carcinogenesis, and biochemistry. The main targets for cancer therapeutics are introduced along with in-depth look at cancer vasculature, tubulin binding agents and their mechanisms of action.In chapter two the development of the routes to the dibenzo[c,e]oxepine target compounds are described. The optimisation of a key biaryl precursor molecule for these analogues is described. This includes a brief overview of palladium catalysed coupling chemistry and a screen for suitable catalytic systems. In chapter three the development of an intramolecular ring closing process for dibenzo[b,d]oxepine is described. This includes investigation into non-phenolic oxidative coupling and a screen for oxidants. Palladium/phosphine catalysed intramolecular arylation is also discussed. In chapter four the synthesis of the target compounds is described along the development of routes to further analogues.In chapter five the biological testing of compounds is discussed. This features an introduction to biological evaluation methods for anti cancer compounds. The results for all of the MTT and tubulin binding assays (MA) are presented, revealing a fluorinated dibenzo[c,e]oxepine analogue with cytotoxicity within the nanomolar range (MTT K562 - IC50 60 nm, MA - 1.2 µM). Furthermore a link has also been established between the cytotoxic activity profiles of a series of simple biaryl compounds and Combretastatin A-4

Fluorinated Prolines as Conformational Tools and Reporters for Peptide and Protein Chemistry

Amide bonds at the proline nitrogen are particularly susceptible to rotation, affording cis and trans isomers. Installation of a stereochemically defined electron-withdrawing fluorine atom or fluorinated groups has the power to influence the cis–trans conformational preferences of the amide bond in X–(F)Pro (where X = any other amino acid). Advantageously, this also provides a sensitive reporter for 19F nuclear magnetic resonance (NMR) studies of protein conformation, interactions, and dynamics. We deliberately use the term “fluorinated prolines” as an all-encompassing term to describe proline analogues containing one or more fluorine atoms and to avoid confusion with the more well-known 4-fluoroprolines. This review presents a critical discussion of the growing repertoire of fluorinated prolines that have been described and, importantly, provides a comparison of their uses and relative influence on amide-bond conformation and discusses the significant potential of using 19F NMR as a tool to probe conformational changes in polypeptides

Expanding the scope of the Babler-Daubin oxidation : 1,3-oxidative transposition of secondary allylic alcohols

We report the catalytic chromium-mediated oxidation of secondary allylic alcohols to give α,β-unsaturated aldehydes with exclusive (E)-stereoselectivity. This facile procedure employs catalytic PCC (5 mol%) and periodic acid (H5IO6) as a co-oxidant. This transformation occurs specifically with aromatic substituted allyl alcohols containing both electron withdrawing and electron donating substituents as well as a range of functional groups

A CGRP receptor antagonist peptide formulated for nasal administration to treat migraine

Objectives: To investigate the formulation of the peptide‐based antagonist (34Pro,35Phe)CGRP27–37, of the human calcitonin gene‐related peptide (CGRP) receptor as a potential nasally delivered migraine treatment. Methods: Peptide sequences were prepared using automated methods and purified by preparative HPLC. Their structure and stability were determined by LC‐MS. Antagonist potency was assessed by measuring CGRP‐stimulated cAMP accumulation in SK‐N‐MC, cells and in CHO cells overexpressing the human CGRP receptor. In vivo activity was tested in plasma protein extravasation (PPE) studies using Evans blue dye accumulation. Peptide‐containing chitosan microparticles were prepared by spray drying. Key findings: (34Pro,35Phe)CGRP27–37 exhibited a 10‐fold increased affinity compared to αCGRP27–37. Administration of (34Pro,35Phe)CGRP27–37 to mice led to a significant decrease in CGRP‐induced PPE confirming antagonistic properties in vivo . There was no degradation of (34Pro,35Phe)CGRP27–37 and no loss of antagonist potency during formulation and release from chitosan microparticles. Conclusions: (34Pro,35Phe)CGRP27–37 is a potent CGRP receptor antagonist both in vitro and in vivo, and it can be formulated as a dry powder with no loss of activity indicating its potential as a nasally formulated anti‐migraine medicine

Novel peptide calcitonin gene-related peptide antagonists for migraine therapy.

Objectives It has previously been shown that the peptide (34Pro,35Phe)CGRP27-37 is a potent calcitonin gene-related peptide, CGRP receptor antagonist, and in this project we aimed to improve the antagonist potency through the structural modification of truncated C-terminal CGRP peptides. Methods Six peptide analogues were synthesized and the anti-CGRP activity confirmed using both in vitro and in vivo studies. Key findings A 10 amino acid-containing peptide VPTDVGPFAF-NH2 (P006) was identified as a key candidate to take forward for in vivo evaluation, where it was shown to be an effective antagonist after intraperitoneal injection into mice. P006 was formulated as a preparation suitable for nasal administration by spray drying with chitosan to form mucoadhesive microcarriers (9.55 ± 0.91 mm diameter) and a loading of 0.2 mg peptide per 20 mg dose.Conclusions The project has demonstrated the potential of these novel small peptide CGRP antagonists, to undergo future preclinical evaluation as anti-migraine therapeutics