A compound of formula (I), which is 2 - [(4S) -6- (4-chlorophenyl) -1-methyl-8- (methyloxy) -4H- [1,2,4] -triazolo- [4, 3-a] [1,4] -benzodiazepin-4-yl] -N-ethyl-acetamide: ** Formula ** or a salt thereof.Un compuesto de fórmula (I), que es 2-[(4S)-6-(4-clorofenil)-1-metil-8-(metiloxi)-4H-[1,2,4]-triazolo-[4,3-a][1,4]-benzodiazepin-4-il]-N-etil-acetamida:**Fórmula** o una sal del mismo.