The present invention provides for compounds of Formula I: wherein R2, R3, R4, R5, R6, R7, X, and L have any of the values defined in the specification, and pharmaceutically acceptable salts thereof, that are useful as agents in the treatment of central nervous disorders and conditions including attention deficit hyperactivity disorder, neuropathic pain, urinary incontinence, anxiety, depression, and schizophrenia and fibromyalgia. Also provided are pharmaceutical compositions comprising one or more compounds of Formula I.