The invention provides a
small molecule compound. The
small molecule compound is characterized in that the
small molecule compound is a compound shown in a
structural formula in the specification, ora stereoisomer, a
geometric isomer, a
tautomer, a racemate, a
hydrate, a solvate, a
metabolite, and a pharmaceutically acceptable salt or pro-
drug thereof, wherein X1 and X2 are selected from carbon or
nitrogen; Z is carbon or
nitrogen; n1 is 0 and 1; n2 and n3 are the same or different, and are 0 or any natural numbers; a cyclic group represented by G is a saturated heterocyclic ring; any one orseveral
hydrogen atoms on the saturated heterocyclic ring are substituted by R; and R is selected from
hydrogen,
halogen,
alkyl, substituted
alkyl, amino, amine group, substituted amine group, carboxyl, amido, substituted amido, ester group, substituted carbonyl, cycloalkyl, substituted cycloalkyl, heterocycloalkyl, substituted heterocycloalkyl,
aryl, substituted
aryl, heteroaryl, substituted heteroaryl, substituted
sulfonyl, and substituted
sulfoxide group. The small molecule compound of the invention can be used to treat, prevent and alleviate autoimmune diseases and / or immune-related inflammatory
skin diseases.