1: N-bromosuccinimide, dibenzyl peroxide / CCl4 / 3 h / Heating; alkaline mother methanolic liquor after XXII was diluted with water and extracted dichlormethane 2: mother liquors after XXIV diluted warwe and extracted with dichlormethane 3: Mg / 1)Grignard reagent in THF 2)15 deg C, 50min, educt XXIV 3)1.5h room temp. View Scheme

1: mother liquors after XXIV diluted warwe and extracted with dichlormethane 2: Mg / 1)Grignard reagent in THF 2)15 deg C, 50min, educt XXIV 3)1.5h room temp. View Scheme

tetrahydrofuran

magnesium 1)Grignard reagent in THF 2)15 deg C, 50min, educt XXIV 3)1.5h room temp.; Yield given. Multistep reaction;

hydrogenchloride in water 1 h; Heating;

2,3-dihydroxybutanedioic acid in water T=90°C; 1 h;

1: aq. HCl / 1 h / 100 °C 2: aq. H2O2 / ethanol / 48 h / Heating View Scheme

1: aq. HCl / 1 h / 100 °C 2: NaBH4 / aq. ethanol / 42 h / Heating View Scheme

1: aq. HCl / 1 h / 100 °C 2: SeO2 / acetic acid / 0.5 h / Heating View Scheme