1: Lawesson's reagent / toluene / 0.5 h / Heating 2: H2S / ethanol / pH 7.4 3: I2; NaHCO3 / ethanol 4: Hg(OAc)2; AcOH / CHCl3 / 0.5 h / 20 °C 5: H2S / ethanol / pH 7.4 6: 90 percent / Lawesson's reagent / toluene / 0.5 h / Heating View Scheme

<b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '3587194', constants.ctx, '0')">iodine</a>;&nbsp;<a href="#" onclick="return RXDsubstances(event, this, '4153970', constants.ctx, '0')">sodium hydrogencarbonate</a>&nbsp;<b>in</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '1718733', constants.ctx, '0')">ethanol</a> <br />Cyclization;&nbsp;<br /> &nbsp;

<b>Multi-step reaction with 2 steps<br /> </b>1: I₂; NaHCO₃ / ethanol<br />2: Hg(OAc)2; AcOH / CHCl₃ / 0.5 h / 20 &deg;C<br /> <br /> &nbsp;