α,α'-Diamino-α,α'-dicarboxyadipic acid tetraester:synthesis, lactamisation and dilactam structure

α,α'-Diamino-α,α'-dicarboxyadipic acid tetraester has been synthesised for the first time; it spontaneously cyclises into a monolactam and, under the action of bases, into a dilactam; the latter forms in the crystal a heterochiral hydrogen-bonded polymer of the linear zig-zag type.