Reagents and conditions: (a) Cs2CO3, anhydrous MeCN, reflux, 18 h, 71%; (b) 1 M HCl, MeOH, 0 °C, 5 min, 99%; (c) Dess–Martin periodinane, anhydrous CH2Cl2, room temp; (d) (i) methanesulfonic anhydride, Et3N, anhydrous CH2Cl2, 0 °C, 15 min, workup, (ii) Cs2CO3, R1R2NH, anhydrous DMF, 90 °C, 15 h or Et3N, anhydrous DMF, 50 °C, 15 h, 17–84%; (e) R1R2NH, anhydrous 1,2-dichloroethane, NaBH(OAc)3, room temp, overnight, 24–69%; (f) 6 M HCl, THF, 50–60 °C, 3 to 8 h or 4 M HCl in dioxane, dioxane/H2O, 50 °C, 16–97%; (g) pyrazole, Cs2CO3, anhydrous MeCN, reflux, 3 h, 80%; (h) THF, 6 M HCl, 50 °C, 4 h, (56 = 70%, 57 = 75%).