Synthesis of Vinca Alkaloids and Related Compounds. Part 84. Sulfonamide Derivatives of Some Vinca Alkaloids with Cardiovascular Activity

(+)?Vincamine ( 1 ) and (+)?vinpocetine ( 2 ) were chlorosulfonylated and the resulting sulfonyl chloride isomers ( 3–6 ) were transformed into sulfonamides ( 7–10 ). The ester group of sulfonamides was modified by selective hydrolysis and transesterification. Apovincaminol derivatives ( 14–16 ) were also prepared by reduction. In addition to the known cerebrovascular effects of the unsubstituted compounds ( 1,2 ), sulfonamides also show a significant peripheral vasodilator effect.