1. Tonabersat or an analogue of formula 1Y represents CR1R1 is acetylR2 represents hydrogen, C3-8cycloalkyl, C16alkyl which is optionally interrupted by oxygen or substituted by hydroxy, C16alkoxy or substituted aminocarbonyl, C16alkylcarbonyl, C16alkoxycarbonyl, C16alkylcarbonyloxy, C16alkoxy, nitro, cyano, halo, trifluoromethyl, or CF3S or a group CF3-A-, Where A is -CF2-, -CO-, -CH2-, CH (OH), SO2, SO, CH2-O Or CONH or a group CF2H-A-, wherein A is oxygen, sulfur, SO, SO2, CF2 or CFH trifluoromethoxy, C16alkylsulfinyl, perfluoro C2-6alkylsulfonyl, C16alkylsulfonyl, C16alkoksisulfinil, C16alkoksisulfonil, aryl, heteroaryl, arylcarbonyl, heteroarylcarbonyl, phosphono, arylcarbonyloxy, geteroarilkarboniloksi, arylsulfinyl, geteroarilsulfinil, arylsulfonyl or heteroarylsulfonyl in which any aromatic moiety is optionally substituted, C16alkylcarbonylamino, C16alkoxycarbonylamino, C16alkyl-thiocarbonyl, C16alkoxy-thiocarbonyl, C16tiokraboniloksi-alkyl, 1-mercapto C16alkyl, formyl or aminosulfinil, aminosulphonyl or aminocarbonyl, any amino wherein the optional part is substituted with one or two C16alkyl groups, or C16alkilsulfinilamino C16alkylsulfonylamino, C16alkoksisulfinilamino or C16alkoksisulfonilamino or etilenilom substituted at the end of C16alkylcarbonyl, nitro or cyano, or -C (C16alkyl) NOH, or -C (C16alkyl) NNH2 or amino optionally zameshennym one or two C16alkyl or C2-7alkanoyl one of R3 and R4 It represents hydrogen or C14alkyl and the other is C14alkyl, CF3 or CH2, Xa represents fluorine, chlorine, bromine, iodine, C14alkoxy, hydroxy, C14alkylcarbonyloxy, -SC14alkyl, nitro, amino optionally substituted by one or two C14alkyl groups, cyano or C14alkoxycarbonyl or R3 and R4 together they represent C2-5polymethylene optionally substituted by C14alkylR5 It represents C16alkylcarbonyloxy, benzyloxy, ONO2, Benzyloxy, phenyloxy or C16alkoxy and R6 and R9 represent hydrogen, or R5 represents hydroxy and R6 It represents hydrogen or C12alkyl and R9 It represents
