1: 1.) trifluoroacetic anhydride (TFAA), 2.) aq. NaHCO3 / acetonitrile / 1.) 0 deg C, 10 min, 2.) RT, 4 h 2: 1,8-diazabicyclo<5.4.0>undec-7-ene (DBU) / diethyl ether / 3 h / Ambient temperature View Scheme

<b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '508906', constants.ctx, '0')">1,8-diazabicyclo[5.4.0]undec-7-ene</a>&nbsp;<b>in</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '741857', constants.ctx, '0')">acetonitrile</a> <br />24&nbsp;h;&nbsp;&nbsp;Ambient temperature;&nbsp;<br /> &nbsp;