FIELD: pharmaceutical industry. SUBSTANCE: present invention describes novel phenylimidazolidinone derivatives of general formula 1: 
wherein n is 1, R1 and R2 are hydrogen, halogen, CN, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 alkylthio, CF3, NO2,; R3 is group II 
or group III 
; R4 is H or C1-C6 alkyl; R5 is H, C1-C6 alkyl or nitrogen protecting group, or pharmaceutically acceptable salt thereof. Said compounds are useful as active ingredient in pharmaceutical composition having 5HT3 antagonistic activity. EFFECT: improved properties of the pharmaceutical composition. 6 cl, 7 ex, 2 tbl
