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With potassium hydroxide; hydrazine; In ethylene glycol; at 190℃; for 13h;
<Synthesis of compound K> After placing compound (77) (96 mg, 0.499 mmol), hydrazine monohydrate (268 mg, 5.35 mmol), potassium hydroxide (294 mg, 5.249 mmol) and ethylene glycol (5 mL) in a heat-dried stoppered test tube, the mixture was slowly heated from room temperature to 190°C and then refluxed at 190°C for 13 hours. After then cooling the mixture to room temperature, water was added and the organic phase was extracted with ether. The organic phase was washed with water and brine and dried over magnesium sulfate, and concentrated under reduced pressure. It was then purified by silica gel column chromatography (hexane:ethyl acetate = 10:1) to obtain the target compound K (59 mg, 66percent yield) as a white solid. The analysis results and chemical formula for the obtained compound K are shown below. Upon measuring the obtained compound K by CV, the oxidation potential was 0.68 V and the reduction potential was -2.88 V. The peak wavelength in the absorption spectrum of compound K was 310 nm. TLC Rf = 0.7 (hexane: CH2Cl2 = 2 :1): 1H NMR (270 MHz, CDCl3): delta 7.17 (d, 2H, J = 4.8 Hz), 7.09 (d, 2H, J = 4.8 Hz), 3.54 (s, 2H): GC-MS (EI): m/z = 178 (M+).