“…In particular, tetrahydropyrano[3,4- b ]indoles have potent antifungal and antibacterial activities, whereas tetrahydro-β-carbolines are known to have antiviral, antiprotozoal, serotonin receptor (5HT) antagonistic, and anticancer properties. 111 Recently, Ghorai et al 112 presented a method (Scheme 68) for the stereoselective synthesis of different 1,4-disubstituted tetrahydro-β-carbolines and tetrahydropyrano[3,4- b ]indoles with high yield. In this two-step, one-pot three-component process, the aziridines/epoxides ring is first broken by LiClO 4 -catalysed S N 2-type reaction using indoles followed by Pictet–Spengler reaction catalysed by p -toluenesulfonic acid.…”