18-crown-6 ether in acetonitrile 4.5 h; Heating; Title compound not separated from byproducts;

1: 52 percent / K2CO3 / benzyltriethylammonium chloride / acetonitrile / 20 h / Heating 2: 20percent aq. KOH / methanol / 2 h / Ambient temperature View Scheme

1: 59 percent / K2CO3 / benzyltriethylammonium chloride (TEBA) / acetonitrile / 24 h / Ambient temperature 2: 97 percent / 20percent aq. KOH / methanol / Ambient temperature View Scheme

1: 61 percent / N-methylpyrrolidone / 1 h / 120 °C / DMSO, DMF 2: 92 percent / conc. HCl, 100percent HCOOH / H2O / 24 h / 125 °C View Scheme