R. Filler, Wei Chen, Sarah M. Woods
Jul 1, 1995
Citations
0
Influential Citations
10
Citations
Journal
Journal of Fluorine Chemistry
Abstract
Abstract Tetrafluoroindole (5), a precursor for potential biologically-active compounds, was prepared previously in a four-step synthesis from C6F6. However, catalytic reduction of pentafluorophenylacetonitrile (2) to 2-pentafluorophenylethyl amine (3) is accompanied by a significant amount of a secondary amine, which, like 3, undergoes cyclization to an indoline and subsequent dehydrogenation to a new indole 8. The side-reaction in the reduction of 2 to 3 is obviated by the use of LiAlH 4 AlCl 3 (1:1). The final aromatization to yield 5 is vastly improved by replacing MnO2 with DDQ.