Synthesis and biological activities of (R)- and (S)-N-(4-Methoxyphenyl)-N,2,6-trimethyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-aminium chloride as potent cytotoxic antitubulin agents.

(R,S)-1 is a potent antimitotic compound. (R)-1·HCl and (S)-1·HCl were synthesized from (R)- and (S)-3-methyladipic acid. Both enantiomers were potent inhibitors of cell proliferation and caused cellular microtubule loss and mitotic arrest. They inhibited purified tubulin assembly and the binding of [(3)H]colchicine to tubulin, with (S)-1 being about twice as potent. Cytotoxicity against 60 tumor cell lines, however, indicated that the (S)-isomer was 10- to 88-fold more potent than the (R)-isomer.