Applicability of some new pyrimidine derivatives for the corrosion inhibition of mild steel in the acidic environment

•A new corrosion inhibitors, ethyl 4[4-(dimethylamino)phenyl]-6-methyl-2-sulfanylidene-1,2,3,4-tetrahydropyrimidine-5-carboxylate (ESP) and 4-[4-(dimethylamino)phenyl]-6-methyl-N-phenyl-2-sulfanylidene-1,2,3,4-tetrahydropyrimidine-5-carboxamide (DSP), have been synthesized and their structures were confirmed by the spectral data.•The anticorrosion property of DSP and ESP on carbon steel were analyzed by electrochemical methods, which revealed that DSP and ESP are an excellent corrosion inhibitors.•The electrochemical studies indicated that DSP and ESP are mixed type inhibitors and get adsorbed on the metal surface by both, physisorption and chemisorption mechanisms.•SEM–EDX studies confirmed the formation of protective inhibitory film of DSP and ESP on the surface of carbon steel.•Quantum chemical parameter obtained from DFT and Monte Carlo simulation studies also supported the data obtained from experimental studies.