1H-Pyrrole-1-dodecanoic acid, 2,5-dihydro-2,5-dioxo-, vincaleukoblastine deriv. NSC618380 Vincaleukoblastine, O(4)-deacetyl-, 4-ester with 2,5-dihydro-2,5-dioxo-1H-pyrrole-1-dodecanoic acid