Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... 3-Acetylindole reacts regioselectively with NO 2 BF 4 in the presence of SnCl 4 to produce 3-acetyl-5-nitroindole or 3-acetyl-6-nitroindole, depending on the temperature, both in excellent yields. ... 3-Acetylindole reacts regioselectively with NO 2 BF 4 in the presence of SnCl 4 ...