Scheme 3.
Synthesis of PbTx acid naphthalene-2-yl ester.a) NaClO2, Na2HPO4, 2-methylbut-2-ene, tBuOH, RT, 4 h, 85%; b) DCC, CH2Cl2, RT, 15 min; c) 2-naphthol, DMAP, CH2Cl2, overnight, 55%.
Synthesis of PbTx acid naphthalene-2-yl ester.a) NaClO2, Na2HPO4, 2-methylbut-2-ene, tBuOH, RT, 4 h, 85%; b) DCC, CH2Cl2, RT, 15 min; c) 2-naphthol, DMAP, CH2Cl2, overnight, 55%.