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. Author manuscript; available in PMC: 2021 Mar 26.
Published in final edited form as: J Med Chem. 2020 Mar 10;63(6):2854–2876. doi: 10.1021/acs.jmedchem.9b01189

Scheme 5.

Scheme 5.

Synthesis of Stage III Analogues 20–33a

aReagents and conditions: (a) K2CO3, DMF; (b) i) 3-aminobenzoic acid or 4-amino benzoic acid, toluene, 130 °C, 2–3 h; ii) NaBH(OAc)3, acetic acid, THF, 12 h, 36–84%; (c) paraformaldehyde, NaBH(OAc)3, EtOH, reflux 2 h, 25 °C, 12 h, 44%; (d) LiOH·H2O, THF/CH3OH/H2O, 12 h, 32%.