FIELD: pharmaceutics.SUBSTANCE: present invention relates to a novel compound of diaminopirimidine formula 1 or its pharmaceutically acceptable salts possessing the properties of 5-HT4 receptors agonist. In formula 1(Formula 1)R1 denotes a phenyl group substituted with one or more substitutes selected from a group consisting of hydroxy, amino, halogen, cyano, nitro, C1-2alkyl (where C1-2alkyl optionally substituted with halogen), C1-5alkoxy,C1-5alkylthio, C1-5alkoxycarbonyl and aminokarbonil, or heteroaryl group selected from a group consisting of furanyl, pyrrolyl, tiofenil, hinolinil, hromenonil, indolil, benzimidazole-4-yl, benzimidazole-5-yl, benzimidazole-6-yl, benzimidazole-7-yl and indazolil, herewith the heteroaryl group can be optionally substituted with one or more substitutes selected from a group consisting of C1-5alkyl (where C1-5alkyl optionally substituted with halogen) and C1-5alkoxy, R2 denotes a nitrogen-containing cyclic group selected from a group consisting of the following formulae from A to D (where * symbol in A-D formulae denotes the position of this group attachment to a compound of formula (1))R3 denotes C1-5alkyl group, optionally substituted by phenyl, R4 denotes hydrogen, C1-5alkyl group optionally substituted with a substitute selected from a group consisting of hydroxy, C1-5alkylamino, pyrrolidinyl and hydroxy-C-1-5alkylamino C1-5alkoxycarbonyl group or amin-carbonyl group, R5 denotes hydrogen, hydroxyl group C1-5alkoxy group C1-5alkyl group, optionally substituted with a substitute selected from a group consisting of amino and C1-5alkoksikarbonilamino or group selected from a group consisting of the following formulae of E to I (where * symbol in E-I formulae is the position of this group attachment to one of the of A-D formula compounds),R6 means hydrogen, hydroxyl group or C1-5alkyl group optionally substituted with hydroxy, X denotes -CH(R7)-, -C(=O)-, -N(R8)- or -O-, R7 means hydrogen hydroxyl group amino-carbonyl group phenyl gr
