Synthesis and biological evaluation of substituted (thieno[2,3-d]pyrimidin-4-ylthio)carboxylic acids as inhibitors of human protein kinase CK2

► Thienopyrimidines are novel and potent class of protein kinase CK2 inhibitors. ► Thienopyrimidines display selectivity towards CK2 and ATP-competitive type of inhibition. ► Key role in the structure of thienopyrimidine CK2 inhibitors plays carboxyl group.