1. Claim 1: a compound of formula (1) and its salts, wherein A1 is ccf8323, A2 is ch, A3 is ch; A1 is ch, A2 is ccf8323, A3 is ch; A1 is n, A2 is ccf8323, A3 is ch; A1 is cch232323, A2 is n, A2 is n, A3 is cochf832222; R1 is C283; C83 is C83; C83 is C83; C83 is C83; C83 is C83; C83 is C83; C83 is C83; C83 is C83; C83 is C83; C83 is C83; C83 is C83; C83 is C83; C83 is C83;Reivindicación 1: Un compuesto de la fórmula (1) y las sales del mismo, en donde A¹ es CCF₃, A² es CH y A³ es CH; o A¹ es CH, A² es CCF₃ y A³ es CH; o A¹ es N, A² es CCF₃ y A³ es CH; o A¹ es CCH₃, A² es N y A³ es COCHF₂; R¹ es alquilo C₁₋₄; y R² es H o alquilo C₁₋₄.