<p>The invention relates to compounds of formula (I), tautomers and salts thereof wherein R1 is methyl or ethyl, R2 is n-butyl or o-methoxyphenyl, R3 is hydrogen or hydroxy; and R4 is hydrogen or methyl. These compounds are receptor tyrosine kinase EphB4 inhibitors useful for the treatment of angiogenesis dependent cancers and intraocular neovascular syndromes.</p>
