A final group of analogues was prepared from dialdehyde 27 by reductive amination, with sodium cyanoborohydride as the reducing agent. This method avoids a potential side reaction, since 33 is reactive enough to form ethers from alcohols in the presence of basic amines. Analogues 23-26 in Table I were prepared in this way. They have one basic nitrogen close in to the anthracene nucleus, but only a hydroxyl group (capable of ...
