Sigma-1 receptor antagonist 6 (Compound 12) is an antagonist of the Sigma-1 receptor ( σ1R ). Sigma-1 receptor antagonist 6 exerts a robust antiallodynic effect by antagonizing σ1R. Sigma-1 receptor antagonist 6 can be used in neuropathic pain animal models to alleviate mechanical allodynia induced by paclitaxel.