2H-BENZOFURAN-3-ONE-DERIVATIVES AND PROCESS FOR THEIR PREPARATION

摘要

This invention relates to a process for the preparation of a compound of formula (I) 'IMAGE> ( I wherein R is hydrogen or C1-C12 alkyl, unsubstituted or substituted by a group, wherein each of R3 and R4 is independently selected from the group consisting of hydrogen and C1-C6 alkyl; R1 is hydrogen, C3-C6 alkenyl or C1-C6 alkyl; R2 is (a) thienyl or furyl, the thienyl and furyl groups being unsubstituted or substituted by a methyl group; or (b) the group wherein each of R5, R6 and R7 is independently selected from the group consisting of (a') hydrogen; (b') the group -(O)-R8, wherein n is zero or 1 and R8 is hydrogen or C3-C4 alkenyl or C1-C6 alkyl; and (c') the group < IMG > wherein R3 and R4 are as defined above, as well as the pharmaceutically acceptable salts thereof, which comprises either: (a) reacting a compound of the formula (II): < IMG > (II) wherein R and R1 are as defined above, with an aldehyde of the formula (III): OHC - R2 (III) wherein R2 is as defined above; or (b) when a compound of formula I is required in which R is a hydrogen atom, hydrolyzing a corresponding ester of the formula (Ia): < IMG > (Ia) wherein R' is a C1-12 alkyl group and R1 and R2 are as defined above; or (c) when a compound of formula (I) is required in which R is C1-12 alkyl group, unsubstituted or substituted by a < IMG > group as defined above, reacting a compound of the formula (Ib): < IMG > (Ib) wherein X is a halogen atom and R1 and R2 are as defined above, with a C1-12 alkanol, unsubstituted or substituted by a < IMG > group as defined above; and where any one of steps (a) to (c) can be followed by the additional step of (d) converting a compound of formula I obtained into a pharmaceutically acceptable salt or (e) separating a mixture of isomers into the single isomers. The compounds of this invention are useful due to anti-allergic and antiulcer activity.