Scheme 2. Synthesis of Amine-linked Analoguesa.
aReagents and conditions: (a) hydrazine, EtOH, reflux, 3 h; (b) propionylchloride, CH2Cl2, TEA, 0 °C to RT, 4 h; (c) LAH, THF, reflux, 4 h (d) aldehyde, Na(OAc)3BH, DCE, RT, 24 h (Method C); (e) 9H-fluorene-2-carbaldehyde, MeOH, RT, 12h; (f) NaBH4, 30 min; (g) HCHO, Na(OAc)3BH, DCE, 12 h.