vincaminic acid derivatives of formula ## str1 ## useful in treating cerebral insufficiency , are prepared by reacting 1 - ethyl - 2 , 3 , 4 , 6 , 7 , 12 - hexahydroindoloquinolizine with the 2 , 4 - dnp hydrazone of ethyl or methyl bromopyruvate followed by reduction of the c ═ n bond and simultaneous cyclization with removal of the ketone - protecting group in either order .