We have demonstrated the use of the room temperature ionic liquid, 1-butyl-3-methylimidazoliumhexafluorophosphate ([bmim]PF₆), as an environmentally benign solvent for the preparation of isoquinoline derivatives through Bischler–Napieralski cyclization under mild conditions with excellent purity and yields. The role of HF as a catalyst in the reaction was also investigated. The effectiveness of the ionic liquid [bmim]PF₆ as a solvent for the Bischler–Napieralski cyclization was examined for the preparation of isoquinoline derivatives.
Tetrahedron Letters Vol. 43, Issue 29, p. 5089-5091