1-SUBSTITUTED 5-NITRO-2-(2-DIALKYLAMINOVINYL)-IMIDAZOLES HAVING TRICHOMONACIDAL ACTIVITY OF THE FORMULA: ##SPC1## Wherein R is H, CH.sub.3 or C.sub.2 H.sub.5 and X is hydrocarbon or hydrocarbon substituted with a halogen or a hydroxy, ether, ester or amino group, are produced by reacting the 1-substituted-5-nitro-2-alkyl-imidazoles with an aminal ester or amidoacetal of orthoformic acid or like functionally reactive derivative thereof.