Abstract Ro 11–2933, 4b, a compound with minor cardiovascular activity has been shown to reverse multidrug resistance in cancer cells as well as chloroquine resistance in Plasmodium falciparum. A useful synthesis of the drug is described. Alkylation of dithiane (2) with chloroalkylamine (3) affords 4b as a crystalline compound in a very good yield. The synthesis of its potential metabolites 7 and 11 has also been carried out.
