Neue Synthese von Vinblastinderivaten; 20′-Deethyl-20′-deoxyvinblastin und 20′-Deethyl-20′-deoxy-C′-homovinblastin Vorläufige Mitteilung

A New Synthesis of the Vinblastine Derivatives 20′-Deethyl-20-deoxyvinblastine and 20′-Deethyl-20′-deoxy-C′-homovinblastine A new synthesis of vinblastine derivatives is described. In the key step, the chloroindolenine derivative 14 was reacted with vindoline ( 2 ) to give, after cyclization, stereospecifically 17/I and 20′-deethyl-20′-deoxyvinblastine ( 17/II ). In an analogous manner, the epimeric C′-homovinblastine derivatives 21/I-21/IV were synthesized.