Preparation of 6-trimethylammoniopurinides and their isomerisation to 3- and 9-methyl analogues of 6-dimethylaminopurines
Abstract
6-Trimethylammoniopurinides, which arise by the action of an excess of trimethylamine on simple 6-chloropurines unsubstituted at either N-7 or N-9, undergo thermal isomerisation, affording the appropriate 6-dimethyl-amino-9-methyl- and 6-dimethylamino-3-methyl-purines by an intermolecular rearrangement. These appear to be the first reported examples of true migration of alkyl groups from an exocyclic nitrogen atom to a ring nitrogen atom in the purine ring system.