Scheme 2. Synthesis of amine derivatives: (h) cat. EDCI, HOBT, Boc-glycine, DCM, rt.12 h; (i) cat. TFA, DCM, rt, 1 h; (j) cat. TEA, 4-nitrobenzenesulfonyl chloride, 0 °C, 0.5 h, rt, 6 h; (k) cat. K2CO3, 1,2-dibromoethane, DMF, 60 °C; (l) cat. LiOH, methyl-mercaptopropionat, CAN/DMSO (v/v = 49/1), 50 °C, 6 h; (m) cat. TEA, DCM, rt; (n) cat. TFA, DCM, 0 °C, 0.5 h, rt, 1.5–4 h; reagents and conditions: (o) cat. PPh3, DEAD, THF, rt; (p) cat. TFA, DCM, rt; (q) cat. NaH, dry DMSO, rt, 0 °C, 0.5 h, rt; (r) cat. NaH, dry DMF, 0 °C, 0.5 h, rt.
