PROCESS FOR THE PREPARATION OF 17,18-DEHYDRO-APOVINCAMINOL-ESTER

摘要

17,18-dehydro-apovincamimol -3',4',5',tri:methyoxy-benzoate (I) is prepd by dehydrating 17,18-dehydro- or 17,18-dehydro -epi vincamine or any arbitrary mixt of these, to yield a 17,18-dehydro-apooimcamine- complex (III) reduced by a metallic-hydride to 17,18-apovincaminol (II). This is esterified with 3,4,5-tri:methoxy-benzoyl-chloride, 17,18-dehydro or 17,18 dehydro-epi-vincamine or opt mixt, dissolved in an organic solvent, reacted at the b.pt. of the solvent in the presence of p-toluenesulphonic-acid. Water produced is removed simultaneously by distn. (III) reacts with Li-Al hydride in mixt. of a hydrocarbon and an ether. Acylation of 17,18-dehydro-apo -viacamine with 3,4,5 tri:methoxy-benzoyl- chloride takes place in the presence of an acid scavenger and the prod is isolated.