Chemical development and process optimization for the synthesis of 2-amino-1-(3-hydroxy-2,6-dimethylphenyl)-5,6-dimethyl-1H-pyrrolo[2,3-b]pyridine-3-carboxamide, an orally bioavailable and selective PKMYT1 inhibitor.

Reagents & conditions: (a) NaNO₂, H₂SO₄, water, 88%; (b) POBr₃, DMF, Toluene, 91%; (c) 1, Pd₂(dba)₃, Xantphos, Cs₂CO₃, (80%); (d) Malononitrile, NaO^tBu, Pd(dppf)Cl₂^.CH₂Cl₂, DME, (78%); (e) H₂SO₄, MeSO₃H, H₂O, then (f) DL-methionine, (75%).

Sygnature Discovery undertook the chemical development and process optimization for RP-6306, Lunresertib^® (WO 2020/195781 A1 & J. Med. Chem. 2022, 65, 15, 10251-10284), an orally bioavailable and selective inhibitor of PKMYT1, a promising therapeutic target implicated in various cancer pathologies. Given its potential in oncology, efficient access to this complex pyrrolopyridine-based molecule was critical for advancing preclinical and clinical investigations.

The original medicinal chemistry synthesis was cumbersome, consisting of nine linear steps yielding a modest 12% overall yield (79% average yield per step). It also required seven chromatographic purifications, posing significant challenges for scalability, economic viability, and transferability into GMP environments.

Leveraging our expertise in chemical process optimization, Sygnature Discovery streamlined the route significantly, reducing the process to five efficient steps, notably incorporating a strategically advantageous one-pot hydration/demethylation sequence. The optimized synthetic approach delivered a dramatically enhanced overall yield of 37% (82% average yield per step) and entirely eliminated the need for column chromatography, thus significantly simplifying scale-up and GMP manufacturing.

The robustness and practicality of our optimized route were confirmed by a successful third-party GMP reproduction at kilogram scale, now published in Organic Process Research & Development (2025, ASAP). Additionally, while both original and optimized routes culminated in a chiral SFC purification, our integrated analytical-to-kilogram scale SFC capabilities ensured seamless progression without presenting a bottleneck.

This significant improvement not only highlights our strength in chemical process innovation but also underscores our ability to meet critical scalability and technology transfer requirements, essential for transitioning RP-6306 efficiently into advanced preclinical and subsequent clinical development phases.