Facile two-step synthesis of crispine A and harmicine by cyclopropylimine rearrangement

The synthesis of 4 and 8 is reported. These intermediates are obtained by a one-pot tandem cyclization of 1 and 6, respectively, via Bischler Napieralski reaction followed by cyclopropylimine rearrangement. Compounds 4 and 8 were reduced by sodium borohydride in methanol to afford cytotoxic alkaloid (±)-crispine A and antileishmania compound (±)-harmicine.