The present invention relates to novel antagonists of the A2B adenosine receptor and pharmaceutical compositions comprising said antagonists as well as their uses for the treatment and prevention of disorders known to be susceptible to improvement by antagonism of the A2B receptor such as asthma, chronic obstructive pulmonary disorder (COPD), pulmonary fibrosis, vascular diseases, allergic diseases, hypertension, retinopathy, diabetes mellitus, inflammatory gastrointestinal tract disorders, inflammatory diseases, autoimmune diseases, renal diseases, neurological disorders and, in particular, cancers. In particular, the present invention relates to compounds of formula (I), wherein R1 represents 1 to 3 identical or different R1 substituents, wherein said R1 is independently at each occurrence selected from hydrogen, halogen, C1-C8alkyl, C1- C8haloalkyl, C1-C8alkoxy, C1-C8hydroxyalkyl and C1-C8alkoxyalkyl； Ra is selected from phenyl, pyridinyl, pyrimidinyl, thiazolyl, thiodiazolyl, oxazolyl, pyrazolyl and triazolyl wherein said phenyl, pyridinyl, thiazolyl, thiodiazolyl, oxazolyl, pyrazolyl and triazolyl is independently optionally substituted by one or more substituents independently selected from halogen, hydroxyl, cycloalkyl, C1-C4alkyl-substituted cycloalkyl, C1-C8alkyl, C1-C8haloalkyl, C1-C8alkoxy, C1-C8alkylaminocarbonyl, C1-C8hydroxyalkyl, C1- C8dialkylaminoC1-C8alkyl, C1-C8aminoalkyl and a heterocycle selected from oxiran, oxetane, aziridine and azetidine wherein said oxiran, oxetane, aziridine and azetidine are independently optionally substituted by halogen, hydroxyl, C1-C4alkyl, C1-C2haloalkyl, C1-C2alkoxy； or Ra is -CONHR' wherein R' is selected from C1-C8alkyl, cycloalkyl, aryl, heteroaryl and C1-C8alkyl-N-morpholino, wherein said aryl, heteroaryl and C1-C8alkyl-N-morpholino is independently optionally substituted by [one or more] substituents selected from halogen, cycloalkyl, C1-C8alkyl, C1-C8alkoxy, C1-C8hydroxalkyl and C1-C8alkoxyalkyl； Ar/Het is sele
