1: C20H18O3 With sodium hexamethyldisilazane in tetrahydrofuran T=-78°C; 0.5 h; Inert atmosphere; 2: p-nitrosobenzene in tetrahydrofuran T=-78°C; Inert atmosphere;

sodium hydrogencarbonate in toluene T=80°C; 12 h; Molecular sieveInert atmosphere;