Abstract: A process for advantageously preparing a piperazinesulfonamide derivative represented by the general formula (III): wherein R1 is hydrogen atom, a straight or branched chain alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, hydroxyl group, trifluoromethyl group, nitro group or amino group; R2 is a phenyl group which may have as substituents on its phenyl ring 1 to 3 groups selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, hydroxyl group, trifluoromethyl group, nitro group and amino group, 2-pyridyl group, 3-pyridyl group or 4-pyridyl group; each of R3 and R4 is independently hydrogen atom, a straight or branched chain alkyl group having 1 to 6 carbon atoms, a hydroxyalkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, or a phenyl group which may be substituted; and Y is an alkylene group having 1 to 12 carbon atoms, and

Abstract: A pyrimidine compound of the formula [I] ##STR1## wherein R1 is H, C.sub.1 -C.sub.4 lower alkyl, halogen atom, --OH, C.sub.1 -C.sub.4 lower alkoxy, C.sub.1 -C.sub.6 hydroxy(lower)alkoxy or --NH.sub.2 ; R2 is H, --NH.sub.2 or --NHCOCH.sub.3 ; R3 is --NR5(CH.sub.2)i--CH.sub.2 OH; R4 is H, halogen atom, --NH.sub.2, --CN, --CHO, --CH.sub.2 OH, --COOH, --CH.sub.2 NH.sub.2, --CONH.sub.2 or --CH.dbd.N--A wherein A is --OH, C.sub.1 -C.sub.4 lower alkyl or C.sub.1 -C.sub.4 lower alkoxy; R5 is H or C.sub.1 -C.sub.4 lower alkyl; and i is an integer of 1 to 4, and an anti-rotavirus agent comprising, as an active ingredient, a compound of the formula [I] wherein R3 is a group selected from the following: ##STR2## The novel pyrimidine compound of the present invention and related derivatives thereof have superior anti-rotavirus action and are useful for the prophylaxis and treatment of rotaviral diseases.