AGGREGATIVE ACTIVATION IN HETEROCYCLIC CHEMISTRY - PART 6 - A SURPRISING NH3 EFFECT DURING METALATION OF 2-METHOXYPYRIDINE WITH A MULTIMETAL COMPLEX BASE - C-3 VERSUS C-6 METALATION

The new bimetallic complex base prepared from Me2N(CH2)(2)OH (DMAE), N aNH2 and BuLi has been found to exhibit a particular behaviour. Thus, the presence of ammonia in these basic aggregates induces the C-3 meta llation of 2-methoxypyridine while the base obtained from DMAE, NaH an d BuLi promoted, like BuLi-DMAELi, metallation at the C-6 position. A reaction profile showed that both metallated species can be obtained b y removing and adding ammonia respectively.