| abstract |
Bicyclic compounds of the general formula (I), <IMAGE> wherein Y<1> and Y<2> represent a removable carbonyl protecting group, and Q is a C1-5 alkyl group or a substituted benzyl group, are prepared in such a way that a) a compound of the general formula (V), <IMAGE> wherein Y<1> and Y<2> are as defined above and R' is a removable amido protecting group other than phenyl group, is activated on the carboxy group and then reacted with a salt of a malonic acid hemiester, wherein the alcohol component is a C1-5 aliphatic alcohol or a substituted benzyl alcohol, the resulting new compound of the general formula (IV), <IMAGE> wherein R', Q, Y<1> and Y<2> are as defined above, is reacted with a sulfonic azide in the presence of a tertiary amine, or b) a compound of the general formula (V) is activated on its carboxy group and reacted then with a diazoacetic acid ester, thereafter the R' protecting group of a resulting new compound of the general formula (III> <IMAGE> is removed, and the resulting compound of the general formula (II> <IMAGE> is subjected to ring closure to form the desired end-product. |