Halamine compounds

Patent Number US 6162452 A1 20001219 SURFACE ACTIVE N-HALAMINE COMPOUNDS... 

Triethoxysilyl propyl)-7,7,9,9-tetramethyl-l,3,8-triazaspiro[4.5]-decane-2 4-dione Figure 9.10 Structure of previously synthesised N-halamine compounds [79]... 

The increasing occurrence of microbial and nosocomial infection has stimulated research activities into antimicrobial polymers and textiles [19, 25, 34]. Most medical textiles and polymeric materials used in hospitals are conductive to crosstransmission of diseases, as most microorganisms can survive on these materials for hours to several months [17, 26]. Thus, it would be advantageous for polymeric surfaces and textile materials to exhibit antibacterial properties so as to reduce and prevent disease transmission and cross-contamination within and from hospitals. N-halamines exhibit a similar antimicrobial potency to chlorine bleach, one of the most widely used disinfectants, but they are much more stable, less corrosive and have a considerably reduced tendency to generate halogenated hydrocarbons, making them attractive candidates for the production of antimicrobial polymeric materials. N-halamine compounds are currently used as antimicrobial additives to produce polymers with antimicrobial and biofilm-limiting activities. 

There are many applications in the medical and food sanitization fields for which antimicrobial surface coatings are needed. There are commercially available products making antibacterial claims, but they are limited in their applications by such factors as a poor spectra of activity, high cost, and toxicity. Work in the laboratories at Auburn Uifiversity over the past two decades has established a novel class of heterocyclic orgaific compounds termed A-halamines that have been demonstrated to be excellent antimicrobial materials for a broad variety of applications. 

A new N-halamine monomeric compound, hydantoin acrylamide (HA), was synthesised by forming a hydantoin ring from the ketone moiety of a secondary amide monomer, N-(l,l-dimethyl-3-oxobutyl)acrylamide (DA), which has been used for coatings and textile applications [76]. Amide and imide moieties of the hydantoin ring halogenate more easily than sterically hindered secondary amides this method can be used to impart antimicrobial properties to films, coatings or paint. HA can be copolymerised with many commercial monomers. 

A special microbicidal treatment based on chlorine is described (Williams, 1999) where cotton is grafted with N-halamines (II, 21.). This compound slowly decomposes releasing chlorine, which is the key to the compounds effectiveness. The treatment can be easily refreshed by a dilute rinse of chlorine bleach and water (as is common to many industrial laundry processes). 

Another safety issue is explosiveness of compounds. This factor is evaluated by the hazards laboratory with tests such as the dust explosion test and the hammer test. Many times we can predict the explosiveness of compounds by looking at their structures. Compounds containing weak bonds between heteroatoms such as in peroxides, hydrazines, halamines and hydroxylamines as well as compounds that can eliminate small, stable molecules like N2, O2, NO, or NO2 (e.g., diazonium, ozonides, nitroso, and nitro compounds) are potentially explosive. 

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