| 摘要 |
<p>The invention relates to a process for the preparation of vinyl pyrimidines of the formula I <CHEM> wherein R<1> is hydrogen or a carboxylic ester group, and R<2> is hydrogen or a group of the formula (a) <CHEM> wherein R<a> is hydrogen, a protecting group or a group easily hydrolyzable under physiological conditions, by reacting a compound of the formula II <CHEM> wherein R<21> is hydrogen or a group (a) wherein hydroxy groups are optionally protected, R<3> is bromo, chloro or iodo, and R<1> is as above, with a vinyl borane compound in the presence of a Pd complex and a base, and optionally, further reacting a product of formula I wherein R<2> is hydrogen with a compound of the formula IV <CHEM> wherein R<b> is a hydroxy protecting group and Z is a leaving group, in the presence of a Lewis acid catalyst.</p> |
