Novel Selective IDO1 Inhibitors with Isoxazolo[5,4-]pyrimidin-4(5)-one Scaffold.

Indoleamine 2,3-dioxygenase 1 (IDO1) is a promising target in immunomodulation of several pathological conditions, especially cancers. Here we present the synthesis of a series of IDO1 inhibitors with the novel isoxazolo[5,4-]pyrimidin-4(5)-one scaffold. A focused library was prepared using a 6- or 7-step synthetic procedure to allow a systematic investigation of the structure-activity relationships of the described scaffold.