| 摘要 |
The acid of formula (I) is made by (a) reacting a cpd. of formula (II) with ethyl aceto-acetate and ethyl ortho-formate in presence of a Lewis acid to obtain a cpd. of formula (III); (b) thermal cyclisation of this to give a cpd. of formula (IV); (c) reacting this with an ethylating agent in presence of a base to obtain a cpd. of formula (V); (d) reacting this with piperazine to give a cpd. of formula (VI); and (e) reacting (VI) with a cpd. of formula M(+)OX(-), in which M is Na or K and X is Cl, Br or I.
|
