A compound of formula A1 or A2 for use in the treatment of a demyelinating peripheral neuropathy: wherein A is COOR5, OPO(OR5)2, PO(OR5)2, SO2OR5, POR5OR5 or 1H-tetrazol-5-yl, R5 being H or an ester-forming group, optionally C1-6alkyl； W is a bond, C1-3alkylene or C2-3alkenylene； Y is C6-10aryl or C2-9heteroaryl eg C3-9heteroaryl, optionally substituted by 1 to 3 radicals selected from halogen, OH, NO2, C1-6alkyl, C1-6alkoxy； halo-substituted C1-6alkyl and halo-substituted C1-6alkoxy； Z is chosen from: wherein the asterisks of Z indicate the point of attachment between &mdash；C(R3)(R4)&mdash； and A of Formula Ia or Ib, respectively； R6 is chosen from hydrogen and C1-6alkyl； and J1 and J2 are independently methylene or a heteroatom chosen from S, O and NR5； wherein R5 is chosen from hydrogen and C1-6alkyl； and any alkylene of Z can be further substituted by one to three radicals chosen from halo, hydroxy, C1-6alkyl； or R6 can be attached to a carbon atom of Y to form a 5-7 member ring； R1 is C6-10aryl or C2-9heteroaryl eg C3-9heteroaryl, optionally substituted by C1-6alkyl, C6-10aryl, C6-10arylC1-4alkyl, C3-9heteroaryl, C3-9heteroarylC1-4alkyl, C3-8cycloalkyl, C3-8cycloalkylC1-4alkyl, C3-8heterocycloalkyl or C3-8heterocycloalkylC1-4alkyl； wherein any aryl, heteroaryl, cycloalkyl or heterocycloalkyl of R1 may be substituted by 1 to 5 groups selected from halogen, C1-6alkyl, C1-6alkoxy and halo substituted-C1-6alkyl or &mdash；C1-6alkoxy； R2 is H, C1-6alkyl, halo substituted C1-6alkyl, C2-6alkenyl or C2-6alkynyl； and each of R3 and R4, independently, is H, halogen, OH, C1-6alkyl, C1-6alkoxy or halo substituted C1-6alkyl or C1-6alkoxy； and the N-oxide derivatives thereof or prodrugs thereof, or a pharmacologically acceptable salt, solvate or hydrate thereof.脱髄性末梢神経障害の治療に使用するための、式Ａ１またはＡ２の化合物：［式中、Ａは、ＣＯＯＲ５、ＯＰＯ（ＯＲ５）２、ＰＯ（ＯＲ５）２、ＳＯ２ＯＲ５、ＰＯＲ５ＯＲ５または１Ｈ－テトラゾール－５－イルであり、Ｒ５は、Ｈまたはエステル形成基、場合によってＣ１～６アルキルであり；Ｗは、結合、Ｃ１～３アルキレンまたはＣ２～３アルケニレンであり；Ｙは、Ｃ６～１０アリールまたはＣ２～９ヘテロアリール例えばＣ３～９ヘテロアリールであり、ハロゲン、Ｏ
