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. 2020 Nov 13;3:174. doi: 10.1038/s42004-020-00411-z

Fig. 4. Synthetic pathways.

Fig. 4

Synthesis of 4-heteroarylbenzoic acid precursors 48m,n,ps (a) and compound 40 (b). Reagents and conditions: (i) Pd(PPh3)4, Na2CO3, dioxane, H2O, 90 °C, 81–90%. (ii) NH2OH·HCl, K2CO3, THF, MeOH, H2O, 0 °C–rt, 42%. (iii) Pd(OAc)2, K2CO3, KCl, Bu4NOAc, DMF, 90 °C, µw, 24%. (iv) K2CO3, MeOH, H2O, 60 °C, 55%. (v) Br2, HOAc, rt, 90%. (vi) ammonium formate, formic acid, DMF, rt, 27%. (vii) LiOH, THF, H2O, 40 °C, 36–99%. (viii) EDC·HCl, DMAP, CHCl3, 75 °C, 78%. (ix) H2, Pd/C, EtOAc, rt, 83%. (x) EDC·HCl, DMAP, CHCl3, 75 °C, 89%.