N-acyl- (3-substituted) -5,6,7,8-tetrahydro- [1,2,4] triazolo [4,3-a] pyrazines as selective antagonists of the NK-3 receptor, pharmaceutical composition, methods for use in disorders mediated by the NK-3 receptor
A compound of Formula I: ** Formula ** or one of the pharmaceutically acceptable solvates thereof, wherein: R1 is H or F; R1 'is H; R2 is H, F or Cl; R2 'is H or F; R3 is F or Cl; R4 is methyl, trifluoromethyl, difluoromethyl, or fluoromethyl; X1 is N and X2 is S; or X1 is S and X2 is N; --- represents a single or double bond depending on X1 and X2.