The present invention is directed to inhibitors of histone deacetylases (HDACs) such as HDAC6, and their use in the treatment of diseases such as cell proliferative diseases (e.g., cancer), neurological (e.g., neurodegenerative disease or neurodevelopmental disease), inflammatory or autoimmune disease, infection, metabolic disease, hematologic disease, or cardiovascular disease.本發明係針對諸如HDAC6之組蛋白脫乙醯基酶(HDAC)之抑制劑,及其於治療諸如以下疾病中之用途:細胞增生疾病(例如,癌症)、神經疾病(例如,神經退化性疾病或神經發育性疾病)、發炎性或自體免疫疾病、感染、代謝疾病、血液學疾病或心血管疾病。