摘要 |
<p>A process for preparing compounds (1) <IMAGE> (1) where Y is NR1R2 or OR, R1 and R2 are hydrogen or C1-3 alkyl, and R is C1-3 alkyl, which comprises protecting the hydroxy group of a compound (2) <IMAGE> (2) cyclising the product under basic conditions and removing the protecting group.</p> |