3NW6:
reference: Proline isosteres in a series of 2,4-disubstituted pyrrolo[1,2-f][1,2,4]triazine inhibitors of IGF-1R kinase and IR kinase., Sampognaro AJ, Wittman MD, Carboni JM, Chang C, Greer AF, Hurlburt WW, Sack JS, Vyas DM, Bioorg Med Chem Lett. 2010 Sep 1;20(17):5027-30. Epub 2010 Jul 15. PMID: 20675137

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