5,6-Dichloro Brorphine

The following information was compiled in December 2025 and is subject to change as new research is conducted and as new information becomes available:

Description: 5,6-Dichloro brorphine is a novel synthetic opioid characterized as an “orphine” analogue and bears structural similarity to other benzimidazolones (e.g., brorphine, chlorphine, 5,6-dichloro desmethylchlorphine). 5,6-Dichloro brorphine was originally synthesized and researched for use for analgesia with a suggested large therapeutic window and decrease of severe adverse side effects (e.g., respiratory depression).^1,2 5,6-Dichloro brorphine was first identified by our laboratory in November 2025 and confirmed after acquiring standard reference material.

Sample Source: CFSRE NPS Discovery Test Purchase Program (Philadelphia, PA)

Sample Appearance: White powder

Pharmacology: 5,6-Dichloro brorphine is a G protein-biased mu-opioid receptor agonist with potency and efficacy values (EC₅₀=8.9±3.8nM, E_max=92±1%) higher than that of fentanyl (EC₅₀=43±9.7nM, E_max=80±5%).^2-5

Toxicology: 5,6-Dichloro brorphine has not been detected in toxicology cases to date at the CFSRE.

Drug Materials: 5,6-Dichloro brorphine has been detected in two drug materials to date at the CFSRE.

Demographics / Geographics: Drug materials originated from an online retailer and New England. 5,6-Dichloro brorphine was identified alone and alongside 5,6-dichloro desmethylchlorphine and MDPiHP.

Legal Status: 5,6-Dichloro brorphine is not currently scheduled in the United States.

Class:

Opioid

Appearance:

White powder

Formula:

C20H20BrCl2N3O

MW:

469.2

[M+]:

469

[M+H]+:

468.0240

IUPAC:

3-[1-[1-(4-bromophenyl)ethyl]-4-piperidyl]-5,6-dichloro-1H-benzimidazol-2-one

Report Date:

December 12, 2025