By the importance of exploring novel compounds for inhibiting the cancerous enzymes activities, this work was performed to recognize advantages of employing 4-amino modified derivatives of cytidine for participating in more efficient interactions with the methyltransferase (MTN) cancerous enzyme target. To this aim, four groups of modified models of cytidine were investigated in addition the original models to recognize the structural features and the corresponding activities. The 4-amino site of cytidine was functionalized by different carbon-based groups in linear and cyclic modes through a bridging peptide linkage. The models were optimized to reach the minimized energy structures by performing quantum chemical calculations and their interactions with the target were analyzed by performing molecular docking simulations. The obtained results of 4-amino modified derivatives of cytidine showed advantages of employing structural modifications to find structures with better molecular orbital based features. Formations of interacting complexes indicated that the additional of carbon-based groups helped to improve possibility of interactions between the substances in both of chemical and physical modes. As a remarkable achievement of this work, the model of cytidine with a phenyl group showed the best advantage of participating in interactions with the MTN target among all twenty five models of the investigated cytidine compounds.