The present invention relates to a prodrug of 5-azacytidine or 2′-deoxy-5-azacytidine having remarkable stability against cytidine deaminase, a metabolic hydrolyzing enzyme in replacement of current injections (5-azacytidine or 2′-deoxy-5-azacytidine) which are clinically used as therapeutic agents for various myelomas including myelodysplastic syndrome. The present invention provides a compound represented by formula (1), or salt thereof,wherein, R is OR3 or a hydrogen atom, R1, R2, and R3 are each independently hydrogen atom or silyl group represented by formula (2):wherein, R1, R5, and R6 are each independently alkyl group which may have a substituent, aryl group which may have a substituent, or arylalkyl group which may have a substituent, with the provision that R1, R2, and R3 are not hydrogen atom simultaneously.
