Inhibitors Carrying a Chloromethoxybenzyl Substituent

Classification according to a substituent is of course unusual, since medicinal chemists conventionally group structures by their common core, thought to define a pharmacophoric element, and a set of substituents which, by definition, do not 

Next to the quinazolines, phthalazines represent the most important heterocyclic series in this class of PDE5 inhibitors. At least two compounds from this category have reached clinical trials E4010 (32) [38] and BMS341400 (33) [39], Both compounds show subnanomolar PDE5 inhibition. Again, a chloromethoxybenzyl substituent seems to be among the preferred substituents in the top part of the molecule polar substituents in the bottom part also characterize this series. 

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