1: With Oxonereg;; (ethylenedinitrilo)tetraacetic acid disodium salt; sodium hydrogencarbonate in acetonitrile T=20°C; Oxidation; 2 h; 2: With potassium hydroxide Hydrolysis; Heating; 3: With toluene-4-sulfonic acid in benzene Cyclization; 2 h; Heating; Further stages. Title compound not separated from byproducts.;

1: With Oxonereg;; (ethylenedinitrilo)tetraacetic acid disodium salt; sodium hydrogencarbonate in acetonitrile T=20°C; Oxidation; 2 h; 2: With potassium hydroxide Hydrolysis; Heating; 3: With toluene-4-sulfonic acid in benzene Cyclization; 2 h; Heating; Further stages. Title compound not separated from byproducts.;

2,6-dimethylpyridine; oxoammonium salt in dichloromethane 24 h; Reflux;