| 摘要 |
The present invention relates to certain 5-substituted pyrimidine nucleosides and pharmaceutically acceptable derivatives thereof of formula (I) <CHEM> wherein X represents a vinylene or ethynylene group; R<1> represents an oxo or imino group; R2 represents hydrogen, a C1-2 alkyl or a C3-4 branched or cycloalkyl group e.g. isopropyl or cyclopropyl; R<3> represents a hydrogen atom or an acyl e.g. C1-4 alkanoyl or benzoyl group optionally substituted for example by one or more halogen, alkyl, hydroxy or alkoxy substituents; and R<4> represents a hydrogen atom or a hydroxy group; providing that (a) when X is ethynyl R<2>, R<3> and R<4> each represents a hydrogen atom, R<1> does not represent an oxo group, and (b) when X represents a vinylene group and R<2> represents hydrogen, R<3> represents an acyl group; or a pharmaceutically acceptable derivative thereof, in the treatment and prophylaxis of varicella zoster virus, cytomegalovirus and Epstein Barr virus infections. Also provided are pharmaceutical formulations and process for the preparation of the compounds according to the invention. |
