Synthesis of the PEQ 5 via key intermediate aniline 11.
aReaction conditions: (a) butyryl chloride, pyr. r.t. (b) AlCl3, 150–175°C 45min then 3h; (c) NaBH4, THF anhy., 0°C; (d) AcOH, 10% Pd/C, 60 psi, 36h; (e) NaH, DMF 30 min then (2bromoethoxy)benzene, 3h; (f) KOH (14 eq.), EtOH:H2O (9:1), reflux, 4h; (g) dimethyl 2(methoxymethylene)malonate, EtOH, reflux; (h) Ph2O, reflux, 12 min