Structure-activity studies on open-chain analogues of nucleosides: Inhibition of S-adenosyl-L-homocysteine hydrolase and antiviral activity 2. Acid open-chain analogues

Over 50 ω-carboxyalkyl derivatives of adenine and other purine bases were examined for their inhibitory effects on rat liver S-adenosyl-L-homocysteine hydrolase and their antiviral activity. To be an inhibitor of SAH-hydrolase the analogue must contain an adenine base substituted at the position 9 by an ω-carboxyalkyl (C 3 -C 5 ) chain bearing at least one hydroxyl function. The absolute configuration at the side-chain is decisive for the dihydroxy and trihydroxy compounds, but less important for the monohydroxyalkanoic acids. D-Eritadenine ( 1a ) and 3-(adenin-9-yl)-2-hydroxypropanoic acids ( 12a ) are the most potent SAH-hydrolase inhibitors and the only compounds possessing an antiviral activity (against vesicular stomatitis, parainfluenza type 3, reovirus type 1, and vaccinia virus). All these compounds effect a rapid irreversible inactivation of SAH-hydrolase. The esters of 1a and 12a exhibit little, if any inhibitory activity toward the enzyme; they are, however, much more potent antiviral agents than the parent compounds 1a and 12a , most probably acting as prodrugs of the latter. 2-Amino-D-eritadenine, (2 R ,3 R )-5-(adenin-9-yl)-2,3-dihydroxypentanoic acid, 9-(dicarboxymethyl)adenine, 4-(adenin-9-yl)-2-hydroxybutanoic acid, 3-(8-bromoadenin-9-yl)-2-hydroxypropanoic acid and O-carboxymethyl derivatives of 9-(2,3-dihydroxypropyl)- and 9-(2,3,4-trihydroxybutyl)adenine are described as novel compounds.