| abstract |
The present invention relates to ester, ether and N-alkylcarbamoyl derivatives of compound (Ia) and pharmaceutically acceptable salts thereof. These compounds exhibit excellent antibacterial activity and are useful for the treatment or prevention of bacterial infections. n n n (wherein R 1 is a hydrogen atom or a methyl group; R 2 a is a hydrogen atom, a protecting group for a hydroxy group, or a methyl group; R 3 is a hydrogen atom or a protecting group for a hydroxy group; R 4 a is a hydrogen atom, a hydroxy group or a protected hydroxy group; R 5 is a hydrogen atom or a protecting group for a hydroxy group; and X is a methylene group or a sulfur atom). The invention also includes compounds which are related to the aforeidentified compounds. |