The present invention relates to substituted 2-(chroman-6-yloxy)-thiazoles of the formula (I), in which Ar, R2, R3 and R4 are as defined in the claims. The compounds of the formula (I) are inhibitors of the sodium-calcium exchanger (NCX), especially of the sodium-calcium exchanger of subtype 1 (NCX1), and are suitable for the treatment of diverse disorders in which intracellular calcium homeostasis is disturbed, such as arrhythmias, heart failure and stroke. The invention furthermore relates to processes for the preparation of the compounds of the formula (I), their use as pharmaceuticals, and pharmaceutical compositions comprising them.
