New methods for synthesis of substituted 2-phenylbenzothiazoles

Weekes, Ashley Ann 2010. New methods for synthesis of substituted 2-phenylbenzothiazoles. PhD Thesis, Cardiff University.

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Abstract

In recent years, substituted 2-arylbenzothiazoles have emerged as an important pharmacophore with a number of possible diagnostic and therapeutic applications. An example of this is provided by the simple 2- 4- aminophenyl benzothiazole series which has shown both exquisite antitumour activity and potential as a PET tracer in non-invasive imaging of Alzheimer's disease. Although there are documented procedures for their synthesis, the majority refer to those benzothiazoles unsubstituted in the benzothiazole ring and involve the use of harsh reaction conditions, and chromatographic purification. In this work a simple method for the rapid access to a range of 2- phenylbenzothiazoles both substituted and unsubstituted in the benzothiazole ring is reported, importantly the method described requires no chromatographic purification. A simple one-step synthesis to 2-phenylbenzothiazoles unsubstituted in the benzothiazole ring is described whereby the desired product was made in high yield and with a short reaction time under either thermal or microwave irradiation of a variety of benzaldehydes and 2-aminothiophenol using sodium metabisulfite as a mild oxidant in DMSO. The methodology was extended to the synthesis of biologically relevant 2- phenylbenzothiazoles substituted on the benzothiazole ring, starting from the appropriately substituted 2-aminophenyldisulfide. Under thermal conditions, a small diverse library of compounds was obtained in short reaction times with no chromatographic purification necessary. The synthesis of a number of 2-phenylbenzothiazoles either substituted or unsubstituted in the benzothiazole ring is also reported by polymer-supported synthesis, utilising polymer-supported triphenylphosphine and p- toluenesulfonic acid as catalysts for the reaction. Biological evaluation was undertaken on four cancer cell lines, namely, A549, LoVo, MCF-7, and PC3, with A549 and MCF-7 the most active. Although no exquisite activity was found, as these compounds contain either or both a carbon and fluorine atom they have the possibility to be labelled with either a 1 C or 18F label and therefore have potential use in PET imaging.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Pharmacy
Subjects:	R Medicine > RM Therapeutics. Pharmacology
ISBN:	9781303195655
Funders:	Welsh School of Pharmacy, Cardiff University
Date of First Compliant Deposit:	30 March 2016
Last Modified:	19 Mar 2016 23:29
URI:	https://orca.cardiff.ac.uk/id/eprint/54377

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