Adenosine a3 receptor agonists

The present invention provides novel compounds of formula (I) which are A3 adenosine receptor agonists and can be used to treat various diseases such as cancer, colitis, leukopenia and neutropenia. In the formula (I), R1 is optionally substituted lower alkyl, optionally substituted cycloalkyl, optionally substituted aryl or optionally substituted heteroaryl, X is covalent bond or optionally substituted alkylene, R2 is a group R4-ZYC <C- or an optionally substituted pyrazolyl group wherein Y is optionally substituted alkylene, Z is oxygen, sulfur or NH, R4 is optionally substituted aryl or optionally substituted heteroaryl, R3 is a hydroxymethyl group or -C (O) -NR5R6 wherein R5 and R6 are each independently hydrogen or lower alkyl. HE