iodine; nitric acid in chloroform 1.) reflux, 4 h, 2.) 5 deg C, 16 h;

1: 1.) Dowex 2(OH-) resin, 2.) 1N HCl / 1.) acetone, water, RT, 24 h 2: DBU, 4A sieves / dimethylformamide; benzene / a.) -15 deg C, 1 h, b.) RT, 18 h 3: 5percent H2SO4 / 3 h / Heating 4: 21 percent / I2, 1N HNO3 / CHCl3 / 1.) reflux, 4 h, 2.) 5 deg C, 16 h View Scheme

1: 5percent H2SO4 / 3 h / Heating 2: 21 percent / I2, 1N HNO3 / CHCl3 / 1.) reflux, 4 h, 2.) 5 deg C, 16 h View Scheme

1: DBU, 4A sieves / dimethylformamide; benzene / a.) -15 deg C, 1 h, b.) RT, 18 h 2: 5percent H2SO4 / 3 h / Heating 3: 21 percent / I2, 1N HNO3 / CHCl3 / 1.) reflux, 4 h, 2.) 5 deg C, 16 h View Scheme

1: 91 percent / tetrabutylammonium fluoride / tetrahydrofuran / 0.5 h 2: 1.) Dowex 2(OH-) resin, 2.) 1N HCl / 1.) acetone, water, RT, 24 h 3: DBU, 4A sieves / dimethylformamide; benzene / a.) -15 deg C, 1 h, b.) RT, 18 h 4: 5percent H2SO4 / 3 h / Heating 5: 21 percent / I2, 1N HNO3 / CHCl3 / 1.) reflux, 4 h, 2.) 5 deg C, 16 h View Scheme