| 摘要 |
<p>A process for preparing a compound of formula (I) where R4 and R5are as defined in the specification; and R6 is hydrogen or a protecting group, which process comprises cyclisation of a compound of formula (II) where R 4, R5and R6 are as defined in relation to formula (I) and R7is a nitrogen-protecting group, and removing protecting group R7-, and thereafter if desired or necessary, removing any protecting group R6 to obtain the corresponding carboxylic acid. Novel intermediates and the use of the products in the preparation of pharmaceutical compounds is also described and claimed.</p> |
