Janos Sapi

Synthesis of vinca alkaloids and related compounds—XVI: New route to the stereoselective synthesis of (+)-vincamine, (-)-vincamone and (+)-apovincaminic acid esters

Abstract A stereoselective method has been elaborated for the synthesis of oxime esters, (-)-4a, b, from which, as common intermediates, (+)-apovincaminic acid esters (3a,b), (+)-vincamine (1) and (-)-vincamone (2) can be prepared.

Synthesis of vinca alkaloids and related compounds XLII: Transformation of vincamone into vincamines via diazomethane assisted homologization. application of 1h-noe measurements for the configurational as

Abstract The α-oxo-acids 4 and 5 derived from vincamone ( 1 ) were transformed into vicamines 2 , 8 , 10 ,respectively by methylene insertion with diazomethane. Homologisation of 3 and 6 dioxo compounds led to oxirane derivatives 8 , 16 , 11 , 13 , 13 , 18 , respectively. Configuration of the oxiranes was determined by 1H-NOE measurements.

Synthesis of vinca alkaloids and related compounds—XVII: Chiral synthesis of vinca alkaloids from l-Tryptophan

Abstract Starting from l -tryptophan two chiral syntheses of the 3S, 17S-lactam 11, an intermediate for the preparation of (+)-vincamine and its derivatives, were elaborated in good overall yield and with an optical purity of 96%.