Scheme 1.

Reagents and conditions: (a) NH₂OH·HCl, 95% ethanol, MeOH, 60 °C, 2 h; (b) Pd/C, H₂, THF, rt, 4 h; (c) 4-acetamido benzenesulfonyl chloride, toluene, pyridine, 100 °C, 2 h, 71%; (d) DMF, K₂CO₃, bromoacetonitrile, rt, 3 h, 53%; (e) DMF, K₂CO₃, 3-bromoprop-1-yne, rt, 3 h, 59%; (f) DMF, K₂CO₃, methyl bromoacetate, rt, 3 h, 54%; (g) DMF, K₂CO₃, 2-bromoacetamide, rt, 3 h, 64%; (h) DMF, NH₄Cl, NaN₃, N₂, 100 °C, 6 h, 67%; (i) DMF, NH₄Cl, NaN₃, N₂, 100 °C, 6 h, 63%; (j) NH₂OH·HCl, NaOH (aq), MeOH, rt, 6 h, 64%; (k) LiAlH₄, THF, NaOH (aq), rt, 3 h, 51%; (l) LiOH, CH₃OH/H₂O, rt, 6 h, 68%.