Provided are a compound of a formula (I) and its pharmaceutically-acceptable salt, which have a glucokinase-activating effect and are therefore useful for treatment of diabetes and obesity. [In the formula, R 1 and R 2 each independently represent a lower alkyl group； X 1 represent a group of a formula (II-1): (wherein R 1 and R 12 each independently represent a hydrogen atom or a lower alkyl group, or taken together with the nitrogen atom to which they are attached, R 1 and R 12 may form a 4- to 7-membered nitrogen-containing aliphatic ring (one carbon atom constituting the 4- to 7-membered nitrogen-containing aliphatic ring may be replaced by an oxygen atom), or taken together with a carbon atom in (CH 2 ) m , R 11 and R 12 may form a 4- to 7-membered nitrogen-containing aliphatic ring； m indicates an integer of from 1 to 3).]
