Pyrrolidine compounds

A compound of formula (I)

• wherein
• R1 is hydrogen, alkylcarbonyl, or arylcarbonyl;
• R2 is alkyl, alkylcycloalkyl, alkylcycloalkylalkyl, cycloalkyl, halogenalkyl, carboxyalkyl, aminoalkyl, (mono- and dialkyl)aminoalkyl, alkoxyalkyl, alkoxycarbonylalkyl, alkinyl, aryl, arylalkyl, arylalkyl(alkoxycarbonyl)alkyl, arylcarbonylalkyl, aryloxyalkyl, arylalkenyl, aryl(alkoxycarbonyl)alkyl, heteroaryl, heteroarylalkyl, heterocyclyl or hetercycylalkyl;
• R3 is hydrogen, aryl, alkyl, or arylalkyl, arylsulfonyl, heteroarylsulfonyl;
• R4 is hydrogen, arylalkyl, alkyl, aryl, cycloalkyl, cycloalkylalkyl, alkylsulfonyl, arylsulfonyl, arylalkylsulfonyl, heteroarylsulfonyl, carboxyalkyl, carboxyalkylsulfonyl, or alkoxycarbonylalkyl;
• or the groups —NR3R4 or R5—[N—N(R4)]—R3 form a saturated or unsaturated 5- or 6-membered aliphatic ring;
• R5 is hydrogen, alkylsulfonyl, arylsulfonyl, heteroarylsulfonyl, alkoxycarbonyl, aryloxycarbonyl, heteroaryloxycarbonyl, alkylcarbonyl, arylcarbonyl, heteroarylcarbonyl, heteroarylalkylcarbonyl, heterocyclyl, (mono- or di-alkylamino)-alkylcarbonyl, (mono- and dialkyl)aminosulfonyl, arylaminocarbonyl, alkyl, alkylcarbonyl, alkoxycarbonyl, aryl, arylalkyl, arylalkoxycarbonyl, or heteroaryl;
• R6 is hydrogen, alkyl, aryl, or carboxyalkyl;
• X is —S(O)2—, —S(O)2—NH—, —C(O)—, —C(O)NR6 or C(O)—O—
• or a pharmaceutically acceptable ester, or a pharmaceutically acceptable salt thereof.