JWH-251, scientifically referred to as 1-pentyl-3-(2-methylphenylacetyl)indole, belongs to the phenylacetylindole family, characterized as a synthetic cannabinoid. It acts as a cannabinoid agonist, exhibiting approximately five times more selectivity for CB1 receptors, with a Ki of 29 nM, compared to CB2 receptors, with a Ki of 146 nM. Similar to its counterparts, such as the 2′-methoxy compound JWH-250, the 2′-chloro compound JWH-203, and the 2′-bromo compound JWH-249, JWH-251 features a phenyl acetyl group instead of the naphthyl ring commonly found in aminoalkyl indole cannabinoid compounds.
In the United States, all CB1 receptor agonists classified under the 3-phenylacetylindole class, including JWH-251, are categorized as Schedule I Controlled Substances. This classification signifies their legal prohibition, as substances in this schedule are considered to have a high potential for abuse and no recognized medical use.

CAS Number864445-39-6 
3D model (JSmol)Interactive image
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1. What is JWH-251?

JWH-251 is a synthetic compound classified as a cannabinoid that belongs to the phenylacetylindole family. It interacts with the endocannabinoid system in the body.

2. How does JWH-251 affect cannabinoid receptors?

JWH-251 acts as a cannabinoid agonist, explicitly showing a significantly higher affinity for CB1 receptors than CB2 receptors.

3. What is its Ki value, and what does it signify?

JWH-251 has a Ki value of 29 nM for CB1 receptors and 146 nM for CB2 receptors. This indicates its binding affinity for these receptors, with a stronger preference for CB1 receptors.

4. How does JWH-251 compare to other compounds in the phenylacetylindole family?

JWH-251 shares similarities with other compounds in the phenylacetylindole family, such as JWH-250, JWH-203, and JWH-249. They all feature a phenylacetyl group but differ in the specific substitution on the indole ring.

5. Is JWH-251 legally available for use?

No, JWH-251 is not legally available for use. It is categorized as a Schedule I Controlled Substance in the United States, indicating that its use is prohibited due to its potential for abuse and lack of recognized medical applications.

6. Are there any known medicinal uses for JWH-251?

JWH-251 is not approved for any medical purposes and is primarily associated with recreational or illicit use.

7. What are the potential effects and risks associated with JWH-251 use?

The effects of JWH-251 can vary but may include altered perception, relaxation, and anxiety. As with many synthetic cannabinoids, there are potential risks and adverse effects, and its safety profile is not well-established.

8. Is JWH-251 related to the “Spice” or synthetic cannabis phenomenon?

JWH-251 and similar compounds have been associated with the production of synthetic cannabis products, often referred to as “Spice” or “K2.” These products are designed to mimic the effects of natural cannabis.

9. Where can I find more information about JWH-251?

For further information about JWH-251, you can refer to scientific literature, drug regulation sources, and credible educational websites. It’s essential to use reliable sources when seeking information about substances of this nature.


  1. In a recent development, Anvisa, the Brazilian Health Regulatory Agency, issued Collegiate Board Resolution No. 804, titled “Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial” (Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control). This resolution, published in Brazilian Portuguese, carries significant implications for the regulation and control of various substances, promoting public safety and health. [Source: Diário Oficial da União, Published on July 25, 2023, Archived from the original on August 27, 2023, Retrieved on August 27, 2023]
  2. Scientific exploration took a remarkable leap in September 2005 when Huffman JW and his team introduced “1-Pentyl-3-phenylacetylindoles.” This groundbreaking work unveiled a novel class of cannabimimetic indoles with potential applications in the field of medicine. Their findings were documented in the Bioorganic & Medicinal Chemistry Letters, Volume 15, Issue 18, Pages 4110–4113. [DOI: 10.1016/j.bmcl.2005.06.008, PMID: 16005223]
  3. Moving forward, the field of medicinal chemistry witnessed an important contribution in April 2008. Manera C, Tuccinardi T, and Martinelli A explored the role of “Indoles and Related Compounds as Cannabinoid Ligands.” This mini-review provided valuable insights into the interaction of indoles and related compounds with the endocannabinoid system. Their work was published in Mini Reviews in Medicinal Chemistry, Volume 8, Issue 4, Pages 370–387. [DOI: 10.2174/138955708783955935, PMID: 18473928]
  4. The legal landscape of controlled substances in the United States is governed by 21 U.S.C. § 812. This federal statute outlines the schedules of controlled substances, including those with recognized medical uses and those deemed illicit due to their potential for abuse. Understanding this legal framework is crucial for comprehending the regulation of various compounds and their impact on society.

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