The substituted benzofurans are a class of chemical compounds based on the heterocyclic and polycyclic compound benzofuran. Many medicines use the benzofuran core as a scaffold, but most commonly the term is used to refer to the simpler compounds in this class which include numerous psychoactive drugs, including stimulants, psychedelics and empathogens. In general, these compounds have a benzofuran core to which a 2-aminoethyl group is attached (at any position), and combined with a range of other substituents. Some psychoactive derivatives from this family have been sold under the street name Benzofury.

Use and effects

+ Compound Chemical name Dose Duration 2-APB 2-(2-Aminopropyl)benzofuran Unknown Unknown 3-APB 3-(2-Aminopropyl)benzofuran Unknown Unknown 4-APB 4-(2-Aminopropyl)benzofuran Unknown Unknown 5-APB 5-(2-Aminopropyl)benzofuran 60–80 mg (20–100 mg+) 3–8 hours 5-MAPB 5-(2-(Methylamino)propyl)benzofuran 30–70 mg (10–120 mg+) 4–8 hours 5-EAPB 5-(2-(Ethylamino)propyl)benzofuran 80 mg (50–150 mg+) Unknown 5-MBPB 6-(2-(Methylamino)butyl)benzofuran Unknown Unknown BK-5-MAPB 5-[2-(Methylamino)propanoyl]benzofuran Unknown Unknown 5-APDB 5-(2-Aminopropyl)-2,3-dihydrobenzofuran 100 mg (50–200 mg+) Unknown 5-MAPDB 5-(2-(Methylamino)propyl)-2,3-dihydrobenzofuran 100 mg (50–150 mg+) Unknown 6-APB 6-(2-Aminopropyl)benzofuran 80–100 mg (15–125 mg+) 6–9 hours 6-MAPB 6-(2-(Methylamino)propyl)benzofuran 50–100 mg (20–130 mg+) 6–8 hours 6-EAPB 6-(2-(Ethylamino)propyl)benzofuran Unknown Unknown 6-MBPB 6-(2-(Methylamino)butyl)benzofuran Unknown Unknown BK-6-MAPB 6-[2-(Methylamino)propanoyl]benzofuran Unknown Unknown 6-APDB 6-(2-Aminopropyl)-2,3-dihydrobenzofuran 70 mg (20–130 mg+) 6–8 hours 6-MAPDB 6-(2-(Methylamino)propyl)-2,3-dihydrobenzofuran Unknown Unknown 7-APB 7-(2-Aminopropyl)benzofuran Unknown Unknown Refs:

Benzofurans like 5-APB and 6-APB are said to have relatively minor psychedelic effects.

Interactions

Pharmacology Pharmacodynamics + Compound Monoamine release (, nM) Ref 5-APB 19 21 31 6-APB 36 14 10 5-MAPB 64–90 24 41–459 (S)-5-MAPB 67 258 (R)-5-MAPB 184 1,951 6-MAPB 33 14 20 5-MABB (5-MBPB) (S)-5-MABB 31 158 210 (R)-5-MABB 49 850 6-MABB (6-MBPB) (R)-6-MABB 172 227 (S)-6-MABB 54 77 41 BK-5-MAPB BK-6-MAPB MDA 160–162 47–108 106–190 MDMA 50–85 54–110 51–278 MBDB 540 3,300 >100,000 Methylone 234–708 140–270 117–220 Notes: The smaller the value, the more strongly the compound produces the effect. The assays were done in rat brain synaptosomes and human potencies may be different. See also Monoamine releasing agent § Activity profiles for a larger table with more compounds.

Benzofurans like 5-APB and 6-APB act as serotonin–norepinephrine–dopamine releasing agents and as serotonin 5-HT2 receptor agonists. In addition, some benzofurans, including 5-MAPB, 6-MAPB, BK-5-MAPB, and BK-6-MAPB, have unexpectedly been found to be potent serotonin 5-HT1B receptor agonists. Along with serotonin release and other actions, this property may be involved may be involved in their entactogenic effects. Conversely, MDMA is much less potent as an agonist of the serotonin 5-HT1B receptor.

Chemistry

History The 2,3-dihydrobenzofurans 5-APDB and 6-APDB were described by David E. Nichols and colleagues at Purdue University as MDMA analogues in 1993. Subsequently, the benzofurans 5-APB and 6-APB emerged as novel designer drugs in 2010. Prior to this, they had been patented by Eli Lilly and Company as serotonin 5-HT2C receptor agonists for potential treatment of eating disorders and seizures in 2000 and 2006. 5-APB and 6-APB are often confused with 5-APDB and 6-APDB. The pharmacology of various benzofurans and 2,3-dihydrobenzofurans was further clarified in the mid-2010s and thereafter.

Society and culture Legal status Substituted benzofurans saw widespread use as recreational drugs by being sold as research chemicals making them exempt from drug legislation. Many of the more common compounds were banned in the UK in June 2013 as temporary class drugs, while others have been made permanently illegal in various jurisdictions.

List of substituted benzofurans

The derivatives may be produced by substitutions at six locations of the benzofuran molecule, as well as saturation of the 2,3- double bond.

The following table displays notable derivatives that have been reported:

Structure Compound CAS # R2 R3 R4 R5 R6 R7 Other 2-APB 30455-73-3 2-aminopropyl H H H H H - 2-MAPB 806596-15-6 2-(methylamino)propyl H H H H H - 2-EAPB 2-(ethylamino)propyl H H H H H - 2-MABB 2-(methylamino)butyl H H H H H - BPAP 260550-89-8 2-(propylamino)pentyl H H H H H - 3-F-BPAP 501901-68-4 2-(3,3,3-trifluoropropylamino)pentyl H H H H H - Brofaromine 63638-91-5 4-piperidinyl H H methoxy H bromo - 3-APB (1-oxa-AMT) 105909-13-5 H 2-aminopropyl H H H H - O-DMT (1-oxa-DMT) H 2-(dimethyl-amino)ethyl H H H H - Dimemebfe (1-oxa-5-MeO-DMT) 140853-58-3 H 2-(dimethyl-amino)ethyl H methoxy H H - Mebfap (1-oxa-5-MeO-AMT) 140853-59-4 H 2-aminopropyl H methoxy H H - 5-MeO-DiBF (1-oxa-5-MeO-DiPT) H 2-(diisopropyl-amino)ethyl H methoxy H H - MiPBF (1-oxa-MiPT) H 2-(methylisopropyl-amino)ethyl H H H H - 4-APB 286834-82-0 H H 2-aminopropyl H H H - DOB-5-hemiFLY(5-MeO-7-Br-4-APDB) H H 2-aminopropyl methoxy H bromo 2,3-dihydro 5-APB 286834-81-9 H H H 2-aminopropyl H H - 5-MAPB 1354631-77-8 H H H 2-(methylamino)propyl H H - 5-EAPB 1445566-01-7 H H H 2-(ethylamino)propyl H H - 5-APB-NBOMe H H H 2-[(2-methoxybenzyl)-amino]propyl H H - 6-APB 286834-85-3 H H H H 2-aminopropyl H - 6-MAPB 1354631-79-0 H H H H 2-(methylamino)propyl H - 6-EAPB 1632539-47-9 H H H H 2-(ethylamino)propyl H - 5-AEDB H H H 2-aminoethyl H H 2,3-dihydro 5-APDB 152624-03-8 H H H 2-aminopropyl H H 2,3-dihydro 5-MAPDB 1354631-78-9 H H H 2-(methylamino)propyl H H 2,3-dihydro 5-EAPDB H H H 2-(ethylamino)propyl H H 2,3-dihydro 6-APDB 1354631-78-9 H H H H 2-aminopropyl H 2,3-dihydro 6-MAPDB 1354631-81-4 H H H H 2-(methylamino)propyl H 2,3-dihydro 6-EAPDB H H H H 2-(ethylamino)propyl H 2,3-dihydro bk-5-MAPB H H H 1-oxo-2-(methylamino)propyl H H - bk-6-MAPB H H H H 1-oxo-2-(methylamino)propyl H - 5-MBPB H H H 2-(methylamino)butyl H H - 6-MBPB H H H H 2-(methylamino)butyl H - 5-DBFPV 2117405-32-8 H H H 1-oxo-2-(pyrrolidin-1-yl)pentyl H H 2,3-dihydro 6-MeO-5-APDB H H H 2-aminopropyl methoxy H 2,3-dihydro F (F-1; 5-MeO-6-APDB) 99355-77-8 H H H methoxy 2-aminopropyl H 2,3-dihydro F-2 99355-74-5 methyl H H methoxy 2-aminopropyl H 2,3-dihydro F-22 952016-51-2 dimethyl H H methoxy 2-aminopropyl H 2,3-dihydro 7-APB 286834-86-4 H H H H H 2-aminopropyl - DOI-2-hemiFLY(4-I-5-MeO-7-APDB) H H iodo methoxy H 2-aminopropyl 2,3-dihydroAmiodarone 1951–25–3propyl3,5-diiodo-4-(2-diethylamino-ethoxy)benzoylHHHH - 2C-B-FLY 733720–95–1HH2-aminoethyl5,6-dihydrofuro[5,6-f] -bromo2,3-dihydro 2C-B-DragonFLY (2C-B-DFLY) 260809–98–1HH2-aminoethylfuro[5,6-f] -bromo - 2C-C-FLY 1354633–83–2HH2-aminoethyl5,6-dihydrofuro[5,6-f] -chloro2,3-dihydro 2C-I-FLY 1354633–88–7HH2-aminoethyl5,6-dihydrofuro[5,6-f] -iodo2,3-dihydro 2C-D-FLY 1354634–07–3HH2-aminoethyl5,6-dihydrofuro[5,6-f] -methyl2,3-dihydro 2C-E-FLY HH2-aminoethyl5,6-dihydrofuro[5,6-f] -ethyl2,3-dihydro 2C-EF-FLY HH2-aminoethyl5,6-dihydrofuro[5,6-f] -2-fluoroethyl2,3-dihydro 2C-T-7-FLY 1354633–05–8HH2-aminoethyl5,6-dihydrofuro[5,6-f] -n-propylthio2,3-dihydro 2C-MeTriox HH2-aminoethyl5,6-methylenedioxy[5,6-f] -methyl2,3-dihydro MeTriox HH2-aminopropyl5,6-methylenedioxy[5,6-f] -methyl2,3-dihydro DOH-FLY (FLY, H-FLY) 219986-80-8 H H 2-aminopropyl 5,6-dihydrofuro[5,6-f] - H 2,3-dihydro DragonFLY (DFLY, H-DFLY) 260809-94-7 H H 2-aminopropyl furo[5,6-f] - H - DOB-FLY 219986–75–1 H H 2-aminopropyl 5,6-dihydrofuro[5,6-f] - bromo 2,3-dihydro Bromo-DragonFLY (DOB-DFLY) 502759–67–3 H H 2-aminopropyl furo[5,6-f] - bromo - DOB-2-DragonFLY-5-ButterFLY 1043541–82–7HH2-aminopropyl5,6-dihydropyrano -bromo - DOM-FLY 748748–08–5HH2-aminopropyl5,6-dihydrofuro[5,6-f] -methyl2,3-dihydro DOMOM-FLY HH2-aminopropyl5,6-dihydrofuro[5,6-f] -methoxymethyl2,3-dihydro 2C-B-FLY-NBOMe 1335331–42–4HH2-[(2-methoxybenzyl)-amino]ethyl5,6-dihydrofuro[5,6-f] -bromo2,3-dihydro 2C-B-DragonFLY-NBOH 1335331–45–7HH2-[(2-hydroxybenzyl)-amino]ethylfuro[5,6-f] -bromo - TFMFly (DOTFM-FLY) 780744–19–6HH2-aminopropyl5,6-dihydrofuro[5,6-f] -trifluoromethyl2,3-dihydro Mescaline-FLY (M-FLY; flyscaline) HH2-aminoethyl5,6-dihydrofuro[5,4-b] -methoxy2,3-dihydro YM-348 372163–84–3ethylH1-(2-aminopropyl)-pyrazol[4,5-f] -HH - 2-Desethyl-YM-348 748116–94–1HH1-(2-aminopropyl)-pyrazol[4,5-f] -HH -

See also Substituted methylenedioxyphenethylamine § Related compounds Substituted 2-aminoindane Substituted amphetamine Substituted benzothiophene Substituted cathinone Substituted methylenedioxyphenethylamine Substituted methoxyphenethylamine Substituted naphthylethylamine Substituted phenethylamine Substituted tryptamine Aminopropylindole

References