1: 1.) Ac2O, H2SO4; 2.) NaOMe / 1.) MeOH, overnight; 2.) MeOH, 30 min 2: 85 percent / 48percent aq. HBr / 1 h / 60 - 65 °C View Scheme

<b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '11343563', constants.ctx, '0')">potassium dihydrogenphosphate</a>;&nbsp;<a href="#" onclick="return RXDsubstances(event, this, '14511978', constants.ctx, '0')">Fremy’s salt</a>&nbsp;<b>in</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '1098229', constants.ctx, '0')">methanol</a> <br />0.5&nbsp;h;&nbsp;&nbsp;Ambient temperature;&nbsp;<br /> &nbsp;