Decoration of an α‑Resorcylate Nucleus as Part of the Manufacture of a Glucokinase Activator

The need to define a set of processes for the manufacture of a glucokinase activator called for an evaluation of different strategies to differentiate the hydroxyls of an α-resorcylic acid derivative. While direct functionalization proved possible, it did not allow access to crystalline intermediates that offered control over the rejection of process impurities. The strategy taken forward involved the installation of a benzoyl protecting group using careful control of pH in order to achieve useful levels of selectivity. This allowed the remaining α-resorcylate hydroxyl to be functionalized using a Mitsunobu reaction, with liquid–liquid partitioning being used to separate downstream intermediates of interest away from the redox byproducts of this reaction. Downstream challenges that were overcome in order to deliver a commercially viable means of manufacturing the API included developing an amidation reaction with a poorly reactive aminopyrazine coupling partner

The Development of a Dimroth Rearrangement Route to AZD8931

Recently, the aminoquinazoline motif has been highly prevalent in anticancer pharmaceutical compounds. Synthetic methods are required to make this structure on a multikilo scale and in high purity. The initial route to aminoquinazoline AZD8931 suffered from the formation of late-stage impurities. To avoid these impurities, a new high-yielding Dimroth rearrangement approach to the aminoquinazoline core of AZD8931 was developed. Assessment of route options on a gram scale demonstrated that the Dimroth rearrangement is a viable approach. The processes were then evolved for large-scale production with learning from a kilo campaign and two plant-scale manufactures. Identification of key process impurities offers an insight into the mechanisms of the Dimroth rearrangement as well as the hydrogenation of a key intermediate. The final processes were operated on a 30 kg scale delivering the target AZD8931 in 41% overall yield