The invention relates to pyridine derivatives of Formula (I)whereinA, R1, R2, R3, R4, R5,andR6are as described in the description, their preparation and their use as pharmaceutically active compounds. Said compounds particularly act as immunomodulating agents.本發明係關於式(I)吡啶衍生物其中A,R1,R2,R3,R4,R5及R6均如說明文中所描述,其製備,及其作為醫藥活性化合物之用途。該化合物係特別充作免疫調制劑。