PROBLEM TO BE SOLVED: To provide a novel organogermanium compound capable of controlling physiological functions of a cis-diol-containing compound via a composition formation.SOLUTION: There is provided a compound represented by the formula (I), a salt or ester thereof, or a polymer thereof. R1 and R2 form a 4- to 10-membered saturated/partially saturated/aromatic cyclic structure together with 2 C to which they bind, R3 is H, halogen and C1-4 alkyl or the like.SELECTED DRAWING: NoneCOPYRIGHT: (C)2019,JPO&INPIT【課題】錯体形成を介してシス-ジオール含有化合物の生理的機能を制御することができる、新たな有機ゲルマニウム化合物の提供。【解決手段】式(I)で表される化合物、その塩、若しくはエステル又はこれらの重合体。(R1及びR2はそれらが結合している2個のCと共に4~10員の飽和/部分飽和/芳香族の環状構造を形成;R3は、H、ハロゲン、C1-4アルキル等)【選択図】なし