Organoboron Compounds as Potential Biocides

Abstract

This thesis describes firstly the synthesis, characterisation and biological testing of a range of analogues of the commercially developed biocide Tebbacop (Chapter Two). The products have been analysed by 11B, 1H, 13C NMR, infrared, ultraviolet, atomic absorption, X-ray photoelectron, and mass spectroscopy, and by gas chromatography. These analyses have provided evidence for complexation of copper(II) in Tebbacop and its analogues by second-sphere coordination. A selection of analogues of Tebbacop have been tested for bioactivity at the Forest Research Institute (FRI, Rotorua) by a rapid screening filter paper technique. These results indicate that different sample preparations of Tebbacop analogues do not provide material of comparable biological activity. The following four chapters report the synthesis and characterisation of a number of organoboron compounds having potential for transfer into the commercial sphere. These compounds all have their origins in the Tebbacop project, in that they are prepared from similar feedstocks and incorporate the same potentially fungicidal components. An investigation into the coordination of boron to novel tripodal amines is reported in Chapter Three. The amine ligands were prepared by Ullman-like coupling of 1-iodo-2-methoxy-5-(1,1,3,3-tetramethylbutyl)benzene with either 2-methoxyaniline or 3,3'-dimethoxybenzidine. The synthesis and relative hydrolytic stabilities of some phenol-derived boratranes is also reported. In Chapter Four the synthesis of some macrocyclic organoboron compounds is described. Calixarenes, cyclotribenzylenes and resorcinarenes were investigated; of these, the resorcinarenes are the most interesting from a commercial perspective. The preparation of a number of tripodal amines from aminoalkylation of 1,3-benzoxazines by phenols is presented in Chapter Five. A series of ligands prepared in this manner were successfully coordinated to boron, giving pseudoboratranes. X-ray crystal structures of four analogues are reported. Chapter Six describes the successful aminoalkylation of oxazine-resorcinarenes. Furthermore, resorcinarenes were found to be suitable aminoalkylating agents and it is proposed that carceplexes and hemicarceplexes can also be prepared using this methodology. Finally, the selective bromination of some resorcinarenes and a pseudoboroatrane derivative are reported.