Scheme. (2) Reagents and conditions: a) piperonylamine, TBTU, iPr₂NEt, CH₃CN, rt, 24 h, 98%; b) 23, Pd(CH₃CN)₂Cl₂, LiCl, Et₃N, DMF, 180 °C, microwave, 1 h, 38%; c) 2-cyanophenylzinc bromide or 3-ethoxycarbonylphenylzinc iodide, Pd(PPh₃)₄, THF, 50 °C, 48 h, 94% for 30, 49% for 36; d) H2 (1 atm), Pd/C, MeOH, HCl, rt, 48 h, 85%; e) 3,4-(methylenedioxy)phenylacetic acid, TBTU, iPr2NEt, CH₃CN, rt, 24 h, 93%; f) 3,4-(methylenedioxy)phenyl isocyanate, Et₃N, DCM, rt, 2 h, 91%; g) piperonyloyl chloride, Et₃N, DCM, rt, 2 h, 100%; h) 23, Pd(CH₃CN)₂Cl₂, LiCl, DMF, 105 °C, 72 h, 4% for 13, 10% for 14; i) 3,4-methylenedioxyphenethylamine, Et₃N, DCM, rt, 1 h, 100%; j) LiOH, MeOH-THF-H₂O, rt, 24 h, 86%; k) 3,4-methylenedioxyphenethylamine or 3-benzo[1,3]dioxol-5-yl-propylamine, TBTU, iPr₂NEt, CH₃CN, rt, 48 h, 83% for 15, 20% for 16.