a Reagents and conditions: (i) Se, NaOH, N2H4 · H2O, DMF, Ar, 60 °C. (ii) NaBH4, ethyl 5-bromovalerate, EtOH, Ar, 0 °C. (iii) (a) aq NaOH, rt, 1 h; (b) TFA/CH2Cl2/thioanisole, rt, 0.5 h. (iv) (a) EtONa, DMF, rt; (b) Br(CH2)7COOEt, reflux, 10 h. (v) 3 M HCl, reflux, 3 h.