Raltegravir (free base) Selective N- v’s O- alkylation of an amide can be challenging and somewhat unpredictable- the outcome being highly dependent on the structure of the substrate. A good example of this is the N-methylated pyrimidone intermediate (5) en route to Merck’s antiretroviral drug Raltegravir.1 Direct methylation of amide (4) (Figure 1) using MeI gives significant