2- Substituted 1,2,3-triazoles, lack

Chemical cellulose esters are relatively stable to UV radiation since they lack aromatic chromophores. Even so, exposure to UV radiation may cause some chain scission and loss of physical properties in cellulose esters exposed to outdoor environments esters formulated for such use must be stabilized accordingly. Some resorcinol and benzophenone derivatives, such as resorcinol monobenzoate and 2-hydroxy-4-methoxybenzophenone, are reportedly excellent UV-light stabilizers for cellulose esters (56,57). Other stabilizers include piperidine derivatives (58) and substituted triazole compounds alone (59) and in combination with resorcinol monobenzoate (60). 

Substituted 1,2,3-triazole 1-oxides 448 have been used for and have a great potential for the synthesis of regioselectively substituted 1,2,3-triazoles 457 which possess their own virtues as mentioned in Section 4.1.7. However, no reports on the biological activity or on the application of 3-substituted 1,2,3-triazole 1-oxides 448 are available. The missing data may be due to the, until recently, lack of a simple synthesis of the 1-oxides 448 based on a direct cyclization. 

The similarity of the UV spectra of s-triazolo[3,2-c]-s-triazoles (see equation 44) and 3-aryl-s-triazoles indicates a lack of electronic interaction between the two fused s-triazole rings. In lH-2,6-diphenyl-s-triazolo[3,2-c]-1s-triazole, the UV spectrum exhibits the resultant effects of the two triazole rings each substituted with an aryl group (66JHC119). 

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