| abstract |
A method for producing a compound represented by the formula: n n nwherein the ring A is a benzene ring which may be substituted in addition to the R′ group; R 1 is hydrogen or an optionally substituted hydrocarbon residue; X is a direct bond or a spacer having an atomic length or two or less between the phenylene group and the phenyl group; Y is —O—, —S(O)m- or —N(R 4 )— wherein m is an integer of 0, 1 or 2 and R 4 is hydrogen or an optionally substituted alkyl group; R′ is carboxyl, an ester thereof, an amide thereof or a group capable of forming an anion or a group convertible thereinto; n is an integer of 1 or 2; or a salt thereof, which comprises deprotecting a compound represented by the formula: n nwherein R is triphenylmethyl, 2-tetrahydropyranyl, methoxymethyl or ethoxy methyl, the other symbols as defined above; or a salt thereof. |