Legal status
Legal status
  • 2-(4-Bromo-2,3,6,7-tetrahydrofuro[2,3-f][1]benzofuran-8-yl)ethanamine
CAS Number
PubChem CID
CompTox Dashboard (EPA)
Chemical and physical data
Molar mass284.153 g·mol−1
3D model (JSmol)
Melting point310 °C (590 °F)
  • NCCc1c2CCOc2c(Br)c3CCOc13
  • InChI=1S/C12H14BrNO2/c13-10-9-3-6-15-11(9)7(1-4-14)8-2-5-16-12(8)10/h1-6,14H2 checkY

2C-B-FLY is a psychedelic phenethylamine and designer drug of the 2C family. It was first synthesized in 1996 by Aaron Monte, Professor of Chemistry at UW-La Crosse.[1]

This molecule was researched a lot by the famous Alexander Shulgin, and it was Ann Shulgin favorite research chemical.[2]


2C-B-Fly in powder form
A space-filling model of the 2C-B-Fly molecule.

2C-B-FLY is 8-bromo-2,3,6,7-benzo-dihydro-difuran-ethylamine. The full name of the chemical is 2-(8-bromo-2,3,6,7-tetrahydrofuro[2,3-f] [1]benzofuran-4-yl)ethanamine. It has been subject of little formal study, but its appearance as a designer drug has led the DEA to release analytical results for 2C-B-FLY and several related compounds.

Analogs and derivatives

Analogues and derivatives of 2C-B:




Substituted benzofurans:



In theory, dihydro-difuran analogs of any of the 2Cx / DOx family of drugs could be made, and would be expected to show similar activity to the parent compounds, 2-CB, DOB, DOM, etc. In the same way that 2C-B-FLY is the dihydro-difuran analog of 2C-B, the 8-iodo equivalent, "2C-I-FLY," would be the dihydro-difuran analogue of 2C-I, and the 8-methyl equivalent, "2C-D-FLY," would be the dihydro-difuran analogue of 2C-D.

Other related compounds can also be imagined and produced in which the alpha carbon of the ethylamine sidechain is methylated, giving the amphetamine derivative DOB-FLY, with this compound being the dihydro-difuran analogue of DOB, which can be viewed as the fully unsaturated derivative of Bromo-DragonFLY.

When only one methoxy group of a 2Cx drug is cyclized into a dihydro-furan ring, the resulting compound is known as a "hemifly", (and these could be termed 2- or 5- "hemis," depending on where the single dihydro-furan ring is placed). And when an unsaturated furan ring is inserted, the compound is known as a "hemi-dragonfly". The larger, fully saturated, hexahydro-benzo-dipyran ring derivative has been referred to as "2C-B-MOTH" or 2C-B-BUTTERFLY. The 8-bromo group can also be replaced by other groups to produce compounds such as TFMFly.

A large number of symmetrical and asymmetrical derivatives can be produced by using different combinations of ring systems. Because the 2- and 5- positions (using the common phenylethylamine numbering scheme), the 2- and 5-positions of the benzene ring, if named as benzo-difurans are not equivalent. Asymmetrical combinations have two possible positional isomers, with different pharmacological activities, at the various 5-HT2 subtypes. These compounds were casually referred to as the "2C-B-GNAT," and "2C-B-FLEA" compounds, which contain 5 or 6 membered rings at the 2- vs. 5-positions, respectively. Isomeric "Ψ"-derivatives with the oxygens positioned at the 2,6- positions, and mescaline analogues with the oxygens at 3,5- have also been made, but both are less potent than the corresponding 2,5- isomers.[7][8] The symmetrical aromatic benzodifuran derivatives tend to have the highest binding affinity at 5-HT2A, but the saturated benzodifuran derivatives have higher efficacy, while the saturated benzodipyran derivatives are more selective for 5-HT2C. A large number of possible combinations have been synthesised and tested for activity, but these represent only a fraction of the many variations that could be produced.[9][10][11][12][13][14][15][16][17][18][19]


Alexander Shulgin lists a dosage of 2C-B-FLY from 10 to 20 mg orally[citation needed].


The toxicity of 2C-B-FLY in humans is unknown. Two deaths occurred in October 2009, in Denmark and the United States, after ingestion of a substance that was sold as 2C-B-FLY in a small-time RC shop, but in fact consisted of Bromo-DragonFLY contaminated with a small amount of unidentified impurities.[20]



As of October 31, 2016; 2C-B-FLY is a controlled substance (Schedule III) in Canada.[21]

United States

2C-B-FLY is unscheduled and uncontrolled in the United States. However, it may fall under the scope of the Federal Analog Act if it is intended for human consumption given its similarity to 2C-B.


The hallucinogenic effect of 2C-B-FLY is mediated by its partial agonistic activity at the 5-HT2A serotonin receptor, but also has a high binding affinity for the 5-HT1D, 5-HT1E, 5-HT1A, 5-HT2B and 5-HT2C receptors.

Researchers suspect that 2C-B-FLY may have a MAOI action, making it dangerous to mix it with drugs like MDMA or Tramadol.[22]


  1. ^ "Erowid 2C-B-Fly Vaults : 2C-B-FLY". erowid.org. Retrieved 2022-11-24.
  2. ^ Ali, Nuit. "2C-B-FLY, Ann Shulgin's Favourite Molecule". chemical-collective.com.((cite web)): CS1 maint: url-status (link)
  3. ^ "Explore N-(2C-B)-Fentanyl | PiHKAL · info". isomerdesign.com.
  4. ^ "Explore N-(2C-FLY)-Fentanyl | PiHKAL · info". isomerdesign.com.
  5. ^ Glennon, Richard A.; Bondarev, Mikhail L.; Khorana, Nantaka; Young, Richard; May, Jesse A.; Hellberg, Mark R.; McLaughlin, Marsha A.; Sharif, Najam A. (November 2004). "β-Oxygenated Analogues of the 5-HT2ASerotonin Receptor Agonist 1-(4-Bromo-2,5-dimethoxyphenyl)-2-aminopropane". Journal of Medicinal Chemistry. 47 (24): 6034–6041. doi:10.1021/jm040082s. ISSN 0022-2623. PMID 15537358.
  6. ^ Beta-hydroxyphenylalkylamines and their use for treating glaucoma
  7. ^ Monte AP; et al. (September 1997). "Dihydrobenzofuran analogues of hallucinogens. 4. Mescaline derivatives". Journal of Medicinal Chemistry. 40 (19): 2997–3008. CiteSeerX doi:10.1021/jm970219x. PMID 9301661.
  8. ^ Chambers JJ, Kurrasch-Orbaugh DM, Nichols DE (August 2002). "Translocation of the 5-alkoxy substituent of 2,5-dialkoxyarylalkylamines to the 6-position: effects on 5-HT(2A/2C) receptor affinity". Bioorganic & Medicinal Chemistry Letters. 12 (15): 1997–9. CiteSeerX doi:10.1016/S0960-894X(02)00306-2. PMID 12113827.
  9. ^ Nichols DE; et al. (January 1991). "2,3-Dihydrobenzofuran analogues of hallucinogenic phenethylamines". Journal of Medicinal Chemistry. 34 (1): 276–81. doi:10.1021/jm00105a043. PMID 1992127.
  10. ^ Monte AP; et al. (July 1996). "Dihydrobenzofuran analogues of hallucinogens. 3. Models of 4-substituted (2,5-dimethoxyphenyl)alkylamine derivatives with rigidified methoxy groups". Journal of Medicinal Chemistry. 39 (15): 2953–61. doi:10.1021/jm960199j. PMID 8709129.
  11. ^ Parker, MA (1998). Studies of perceptiotropic phenethylamines: Determinants of affinity for the 5-HT2A receptor (PhD. Thesis). Purdue University. Archived from the original on 2012-04-25. Retrieved 2011-12-16.
  12. ^ Chambers JJ, Kurrasch-Orbaugh DM, Parker MA, Nichols DE (March 2001). "Enantiospecific synthesis and pharmacological evaluation of a series of super-potent, conformationally restricted 5-HT(2A/2C) receptor agonists". Journal of Medicinal Chemistry. 44 (6): 1003–10. CiteSeerX doi:10.1021/jm000491y. PMID 11300881.
  13. ^ Whiteside MS; et al. (October 2002). "Substituted hexahydrobenzodipyrans as 5-HT2A/2C receptor probes". Bioorganic & Medicinal Chemistry. 10 (10): 3301–6. CiteSeerX doi:10.1016/S0968-0896(02)00209-2. PMID 12150876.
  14. ^ Chambers JJ; et al. (July 2003). "Synthesis and pharmacological characterization of a series of geometrically constrained 5-HT(2A/2C) receptor ligands". Journal of Medicinal Chemistry. 46 (16): 3526–35. CiteSeerX doi:10.1021/jm030064v. PMID 12877591.
  15. ^ Schultz DM; et al. (June 2008). ""Hybrid" Benzofuran–Benzopyran Congeners as Rigid Analogues of Hallucinogenic Phenethylamines". Bioorganic & Medicinal Chemistry. 16 (11): 6242–51. doi:10.1016/j.bmc.2008.04.030. PMC 2601679. PMID 18467103.
  16. ^ Evans, Paul (2000). Design and Synthesis of Novel 5-HT2A/2C Receptor Agonists (PDF) (PhD.). University of Wisconsin-La Cross. Archived from the original (PDF) on 2011-07-16. Retrieved 2010-05-27.
  17. ^ Heim, Ralf (2004). Synthese und Pharmakologie potenter 5-HT2A-Rezeptoragonisten mit N-2-Methoxybenzyl-Partialstruktur. Entwicklung eines neuen Struktur-Wirkungskonzepts (PhD.). Der Freien Universität Berlin.
  18. ^ Braden, Michael Robert (2007). Towards a biophysical understanding of hallucinogen action (PhD.). Purdue University. ProQuest 304838368.
  19. ^ Silva, Maria (2009). Theoretical study of the interaction of agonists with the 5-HT2A receptor (PhD.). Universität Regensburg.
  20. ^ "Erowid 2C-B-Fly Vault: Death Reports 2009". www.erowid.org. Retrieved 18 December 2022.
  21. ^ Regulations Amending the Food and Drug Regulations (Part J — 2C-phenethylamines)
  22. ^ Thomas S. Ray (February 2010). "Psychedelics and the Human Receptorome". PLOS ONE. 5 (2): e9019. Bibcode:2010PLoSO...5.9019R. doi:10.1371/journal.pone.0009019. PMC 2814854. PMID 20126400.