Scheme 11. Synthesis of Derivatives with a para Substituent on the Phenyl Ring.

Reagents and conditions: (a) nucleophile, K₂CO₃, MeCN, 0–22 °C, 24 h. (b) NaBH₄, 0–22 °C, 2 h; (c) 2s, PPh₃, DIAD, THF, 22 °C, 18 h; (d) Fe, AcOH, 22 °C, 2 h; (e) KSCN, Br₂, AcOH, 22 °C, 15 h; (f) 46s, Na₂CO₃, DMF, 65 °C, 24 h; (g) 2 M NaOH, MeOH, 40 °C, 48 h; (h) 4 M HCl in dioxane, 22 °C, 1 h; (i) 2-trichloroacetyl-4-chloro-5-methyl-1H-pyrrole, Na₂CO₃, DMF, 65 °C, 18 h; (j) 4-fluoro-5-methyl-1H-pyrrole-2-carbonyl chloride, toluene, 130 °C, 18 h; and (k) 4-cyano-5-methyl-1H-pyrrole-2-carbonyl chloride, toluene,130 °C, 18 h.