2-Substituted-5'-O-(1-boranotriphosphate)adenosine derivatives having at position 2 a radical R1 selected from the group consisting of H; halogen; O-hydrocarbyl; S-hydrocarbyl; NR3R4; and hydrocarbyl optionally substituted by halogen, CN, SCN, NO2, OR3, SR3 or NR3R4; wherein R3 and R4 are each independently H or hydrocarbyl or R3 and R4 together with the nitrogen atom to which they are attached form a saturated or unsaturated heterocyclic ring optionally containing 1-2 further heteroatoms selected from oxygen, nitrogen and sulfur, and pharmaceutically acceptable salts or diastereoisomers thereof or a mixture of diastereoisomers, are useful for treatment of type 2 diabetes.