PROBLEM TO BE SOLVED: To provide compounds useful for reducing the production of visual cycle products.SOLUTION: The present invention provides a compound having a structure represented by formula (1) (X is C(Ri)(Rj), or O； T is CH2, CH2CH2 or a direct bond； R1 and R2 independently represent -CH3 or -CH2CH3； R3, Ra and Rb independently represent H, -CH3, or -CH2CH3； R4 is H, or -CH3； Ri and Rj independently represent H, D, OH, F, alkoxy, lower alkyl or lower haloalkyl； Ri and Rj may be combined as oxo (=O)； B is a phenyl group which may comprise a substituent).SELECTED DRAWING: None【課題】視覚サイクル生成物の産生の低減に有用な化合物の提供。【解決手段】式（１）で表される構造を有する化合物。（ＸはＣ（Ｒｉ）（Ｒｊ）、又はＯ；ＴはＣＨ２、ＣＨ２ＣＨ２又は直接結合；Ｒ１及びＲ２は各々独立に－ＣＨ３又は－ＣＨ２ＣＨ３；Ｒ３、Ｒａ及びＲｂは夫々独立にＨ、－ＣＨ３、又は－ＣＨ２ＣＨ３；Ｒ４はＨ、又は－ＣＨ３；Ｒｉ及びＲｊは夫々独立にＨ、Ｄ、ＯＨ、Ｆ、アルコキシ、低級アルキル又は低級ハロアルキル；ＲｉとＲｊは、オキソ（＝Ｏ）として統合してもよく；Ｂは置換基を有してもよいフェニル基等）【選択図】なし
