Reagents and conditions: (a) benzyl chloroformate, EtOH, 0°C, 1 h; (b) Na2CO3, H2O, 15°C, 1 h; (c) 2-chloroacetyl chloride, toluene, 110°C, 3 h; (d) R1H, toluene, 110°C, 6 h; (e) 10% Pd/C, MeOH, H2 (15 psi), 25°C, 12 h; (f) (Boc)2O, MeOH, 25°C, 3 h; (g) 2-propanol, Na, 90°C → 60°C, 30 min; (h) Boc2O, Pd/C, MeOH, H2 (15 psi), 25°C, 2 h; (i) pyrrole, DMF, NaH, N2, 0°C to 25°C, 12 h; (j) Pd/C, H2 (15 psi), EtOAc, 25°C, 4 h; (k) alkyl chloroformate, THF, Et3N, 0°C to 25°C, 2 h.
#Purified or unpurified intermediate, with partial structural characterization (1H NMR, MS, or both).
*An intermediate chemical prepared, purified or unpurified, and used as raw starting material for the next step without structural characterization.