A practical synthesis of 7-azaindolylcarboxy-endo-tropanamide (DF 1012)

An optimised cost-effective synthesis of the new antitussive drug, DF1012, is herewith reported. The new synthetic route to the key intermediate DF1005 is based on the unusual deprotection step of the 1-tert-butyl-3-cyano-7-azaindole intermediate, which can also be regarded as a convenient way for the industrial production of the expensive 7-azaindole 1. The second key intermediate, endo-tropanamine 6, was obtained in high yield by a novel one-pot stereoselective process using a Pd-catalysed reductive amination procedure.