4- -phthalazinone effect

AO is also effective in metabolizing a wide range of nitrogen-containing heterocycles such as purines, pyrimidines, pteridines, quinolines, and diazanaphthalenes (95). For example, phthalazine is rapidly converted to 1-phthalazinone by AO and the prodrug, 5-ethynyl-2-(l//)-pyrimidone, is oxidized to the dihydropyrimidine dehydrogenase mechanism-based inhibitor, 5-ethynyluracil, by AO (Fig. 4.40) (96). 

The chemistry of these phthalazines has been better explored than might be expected, probably because of the biological activities possessed by some. For example, the marked bronchodilatory effects of 2-ethyl-4-(pyridin-3-yl)-l(2//)-phthalazinone (209) and 4-(p-chlorobenzyl)-2-(l-methylhexahydro-17/-azepin-4-yl)-l(2//)-phthalazinone hydrochloride (Azelastin) (210) ° led to the synthesis and investigation of a variety of phthalazinone, fused phthalazine, and nonphthalazine analogs as antiasthmatics. " " °° ... 

The majority of polymer membranes used for microfiltration and ultrafiltration of liquids are prepared by the wet phase inversion process. Such membranes exhibit a typical asymmetric structure characterized by a thin dense surface layer and a thick microporous bulk. Poly(phthalazinone ether sulfone ketone) (PPESK) copolymers, c.f. Figure 7.10, show glass transition temperatures in the range of 263-305°C. The polymers show an outstanding chemical stability. They are soluble only in 98% H2SO4. Concentrated aqueous solutions of sodium chlorate, hydrogen peroxide, acetic acid, and nitric acid show no effect. ... 

Jian XG, Xing DB, Zhang SH, Yin CX, Zhang BG. Effect of amination agent on the properties of quatemized poly(phthalazinone ether sulfone) anion exchange membrane for vanadium redox flow battery application. J Membr Sci 2010 354 68-73. 

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