The synthesis of the isomeric N-methyl derivatives of murexine

The two isomeric N-methyl derivatives of murexine have been synthesised by independent routes and shown to be different from an 'N- methylmurexine' reportedly isolated from the mollusc Nucella emarginata. 1H n.m.r. studies have shown a marked difference in the extent of binding to paramagnetic ions of the two N-methyl derivatives of murexine in water while pharmacological results show substantially different pharmacological activities of the two isomers. Both results can be rationalized in terms of the observed activities being associated with the presence of one or the other of the tautomeric forms of the imidazole ring.