1: 1.) oxalyl chloride, DMSO / 1.) CH2Cl2, -82 deg C, 3 min, 2.) CH2Cl2, from -82 deg C to -67 deg C, 30 min 2: Et3N / CH2Cl2 / 0.03 h / Heating View Scheme

<b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '472690', constants.ctx, '0')">toluene-4-sulfonic acid</a>&nbsp;<b>in</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '635760', constants.ctx, '0')">toluene</a> <br />6&nbsp;h;&nbsp;&nbsp;Heating;&nbsp;<br /> &nbsp;