aReagents and conditions: (i) Ac2O, CH3CN, Et3N, reflux; (ii) SOCl2, DMF, CHCl3, reflux; (iii) NH3, MeOH; (iv) R1NH2, EtOH, 80 °C, 2h; (v) 2 equiv. SOCl2, acetone, pyridine, overnight, then aq. NH3; (vi) RH, reflux; (vii) acetone, SOCl2, CH(OMe)3; (viii) thioacetic acid, PPh3, diisopropyl azodicarboxylate, THF; (ix) NaOMe, then RBr, MeOH; (x) HCl, dioxane/H2O; (xi) phthalimide, PPh3, diisopropyl azodicarboxylate, THF; (xii) NH2NH2, EtOH, 80 °C; (xiii) RBr or RI, diisopropylethylamine, DMF; (ixv) acetone, AcOH, NaCNBH3, MeOH; (xv) methyl acrylate, MeOH; (xvi) LiAlH4, THF; (xvii) RNCO, CH2Cl2.