PROBLEM TO BE SOLVED: To provide a compound having safety and storage stability which can be commercially practical as an active ingredient of a therapeutic agent for a neurodegenerative disease and the like, and a pharmaceutical composition comprising the compound.SOLUTION: The present invention provides a compound represented by formula (1) (where R is a C1-6 alkyl group, X is O or S, Y is an organic carboxylic acid selected from fumarate, citric acid, malic acid, and succinic acid, and n is 0-5 (where, n is not 0). There is also provided a pharmaceutical composition comprising the compound.SELECTED DRAWING: NoneCOPYRIGHT: (C)2016,JPO&INPIT【課題】神経変性疾患等の治療薬の医薬原体として実用化が可能な安全性および保存安定性を有する化合物及び該化合物を含有する医薬組成物等の提供。【解決手段】式(1)(式中、RはC1-6アルキル基を表し、Xは、OまたはSを表し、Yは、フマル酸、クエン酸、リンゴ酸、およびコハク酸から選択される有機カルボン酸を表し、nは0~5(但し、nは0ではない)を表す。)で表される化合物及び当該化合物を含む医薬組成物。【選択図】なし