“…Additionally, we have recently reporteed some of these compounds with both abilities to inhibits the acetylcholinesterase enzyme and low human toxicity. [31] , [32] , [33] Among the various phosphoramide derivatives [ 31 , [33] , [34] , [35] ], we have studied phosphoguanidines and phosphopyrazines as effective compounds in drug design because of their extensive biological properties [ 31 , 33 ]. Due to the fact that Phosphoramides are able to inhibit the main protease [36] , In this work we selected 35 phosphoramide compounds including the guanidine and pyrazine with the general formula (R 1 )(R 2 )P(X)–Y, that X=O or S, Y= creatine, amino pyrazine, amino benzimidazole, or amino pyrimidines, R 1 =(C 6 H 5 , OC 6 H 5 , OCH 3 , or OCH 2 CH 3 ), and R 2 =(R, Y) ( Figure 1 , Table 1 ).…”