Overview of structures and yields of intermediates 3 and 4 (shown in “S1 Fig.”) and analogs 5 (as described in “<b><i>Supporting Information</i></b>”) with PKD1 inhibition data for analogs 5.

aPiperazine is directly connected to the pteridine core without a secondary amine. bVia the PyBOP route. cVia the chlorination/substitution route (2-step yield). Overview of structures and yields of intermediates 3 and 4 (shown in “S1 Fig.”) and analogs 5 (as described in “Supporting Information”) with PKD1 inhibition data for analogs 5.