Piperazine derivatives and methods of use

A method for treating infertility in a human female, comprising administering to a human female suffering from or suspected of suffering from infertility a therapeutically effective amount of a compound of Formula I:

• wherein R1 is H;
• R2 is selected from aryl and heteroaryl;
• R3 is selected from C1-C16-alkyl, C2-C16-alkenyl, C2-C16-alkynyl, monocyclic aryl, monocyclic heteroaryl, 3-8-membered monocyclic cycloalkyl, monocyclic heterocycloalkyl, acyl, C1-C16-alkyl aryl, C1-C16-alkyl heteroaryl, C2-C16-alkenyl aryl, C2-C16-alkenyl heteroaryl, C2-C16-alkynyl aryl, C2-C16-alkynyl heteroaryl, C1-C16-alkyl cycloalkyl, C1-C16-alkyl heterocycloalkyl, C2-C16-alkenyl cycloalkyl, C2-C16-alkenyl heterocycloalkyl, C2-C16-alkynyl cycloalkyl, C2-C16-alkynyl heterocycloalkyl, alkoxycarbonyl, aminocarbonyl, C1-C16-alkyl carboxy, C1-C16-alkyl acyl, aryl acyl, heteroaryl acyl, C3-C8-(hetero)cycloalkyl acyl, C1-C16-alkyl acyloxy, C1-C16-alkyl alkoxy, C1-C16-alkyl alkoxycarbonyl, C1-C16-alkyl aminocarbonyl, C1-C16-alkyl acylamino, acylamino, sulfmyl, C1-C16-alkyl sulfanyl, C1-C16-alkyl ureido, C1-C16-alkyl carbamate, C1-C16-alkyl amino, and C1-C16-alkyl ammonium;
• R4 is selected from C1-C12-alkyl, C2-C12-alkenyl, C2-C12-alkynyl, aryl, heteroaryl, 3-8-membered cycloalkyl, heterocycloalkyl, and amino;
• and pharmaceutically acceptable salts thereof.