Pyridin-4-yl derivatives as immunomodulating agents

A compound of the Formula (I),

• wherein
• A represents *—CONH—CH2—, *—CO—CH═CH—, *—CO—CH2CH2—,
• wherein the asterisks indicate the bond that is linked to the pyridine group of Formula (I);
• R1 represents C1-4-alkyl, or chloro;
• R2 represents C1-5-alkyl, C1-4-alkoxy, or C3-6-cycloalkyl;
• R3 represents hydrogen, C1-4-alkyl, C1-4-alkoxy, or halogen;
• R4 represents hydrogen, C1-4-alkyl, C1-4-alkoxy, halogen, trifluoromethyl, or trifluoromethoxy;
• R5 represents 2,3-dihydroxypropyl, di-(hydroxy-C1-4-alkyl)-C1-4-alkyl, —CH2—(CH2)k—NHSO2R53, —(CH2)nCH(OH)—CH2—NHSO2R53, —CH2—(CH2)k—NHCOR54, —(CH2)nCH(OH)—CH2—NHCOR54, —CH2—(CH2)n—CONR51R52, —CO—NHR51, 1-(3-carboxy-azetidinyl)-2-acetyl, 1-(2-carboxy-pyrrolidinyl)-2-acetyl, 1-(3-carboxy-pyrrolidinyl)-2-acetyl, 1-(3-carboxy-azetidinyl)-3-propionyl, 1-(2-carboxy-pyrrolidinyl)-3-propionyl, 1-(3-carboxy-pyrrolidinyl)-3-propionyl, —(CH2)nCH(OH)—CH2—NR51R52, hydroxy, hydroxy-C2-5-alkoxy, di-(hydroxy-C1-4-alkyl)-C1-4-alkoxy, 2,3-dihydroxy-propoxy, 2-hydroxy-3-methoxy-propoxy, —OCH2—(CH2)m—NR51R52, 2-[(azetidine-3-carboxylic acid)-1-yl]-ethoxy, 2-[(azetidine-3-carboxylic acid C1-5-alkylester)-1-yl]-ethoxy, 2-[(pyrrolidine-3-carboxylic acid)-1-yl]-ethoxy, 2-[(pyrrolidine-3-carboxylic acid C1-5-alkylester)-1-yl]ethoxy, —OCH2—CH(OH)—CH2—NR51R52, 3-[(azetidine-3-carboxylic acid)-1-yl]-2-hydroxypropoxy, 3-[(azetidine-3-carboxylic acid C1-5-alkylester)-1-yl]-2-hydroxypropoxy, 2-hydroxy-3-[(pyrrolidine-3-carboxylic acid)-1-yl]-propoxy, 2-hydroxy-3-[(pyrrolidine-3-carboxylic acid C1-5-alkylester)-1-yl]-propoxy, 2-hydroxy-3-[(pyrrolidine-2-carboxylic acid)-1-yl]-propoxy, 2-hydroxy-3-[(pyrrolidine-2-carboxylic acid C1-5-alkylester)-1-yl]-propoxy, —OCH2—(CH2)m—NHSO2R53, —OCH2—CH(OH)—CH2—NHSO2R53, —OCH2—(CH2)m—NHCOR54, —OCH2—CH(OH)—CH2—NHCOR54;
• R51 represents hydrogen, C1-3-alkyl, 2-hydroxyethyl, 2-hydroxy-1-hydroxymethyl-ethyl, 2,3-dihydroxypropyl, carboxymethyl, 1-(C1-5-alkylcarboxy)methyl, 2-carboxyethyl, or 2-(C1-5-alkylcarboxy)ethyl;
• R52 represents hydrogen, methyl, or ethyl;
• R53 represents C1-3-alkyl, methylamino, ethylamino, or dimethylamino;
• R54 represents hydroxymethyl, hydroxyethyl, aminomethyl, methylaminomethyl, dimethylaminomethyl, aminoethyl, 2-methylamino-ethyl, or 2-dimethylamino-ethyl;
• k represents the integer 1, 2, or 3;
• m represents the integer 1 or 2;
• n represents 0, 1, or 2;
• and
• R6 represents hydrogen, C1-4-alkyl, or halogen;
• in free or salt form.