formic acid 0.05 h;

<b>Multi-step reaction with 4 steps<br /> </b>1: 1.) hexamethyldisilazane, ammonium sulfate / 1.) 2 h, reflux, 2.) acetonitrile, 65 h<br />2: 96 percent / pyridine / 120 h / Ambient temperature<br />3: 100 percent / dimethylformamide / 10 h / Ambient temperature<br />4: 45 percent / 2,2'-azobis(methylpropionitrile), tri-n-butyltin hydride / toluene / 3 h / Heating<br /> <br /> &nbsp;