Réaction #1772044

Équation de réaction

Thionyl chloride

6-(3-bromophenyl)hexanoic acid

aluminum trichloride

→

2-bromo-7,8,9,10-tetrahydrobenzo[8]annulen-5(6H)-one

Rendement 67.4%

Solvants

carbon disulfide

Conditions de réaction

Traitement

1. 1
   Autreexcess reagent was removed in vacuo
2. 2
   workup.DISSOLUTIONThe acid chloride was dissolved in carbon disulfide (550 mL)
3. 3
   Températureheated
4. 4
   Températureat reflux
5. 5
   Températurecooled
6. 6
   Autredecanted
7. 7
   Concentrationconcentrated
8. 8
   workup.STIRRINGthe resultant solids were stirred in diethyl ether/THF (1:1, 1 L)
9. 9
   workup.WAIT1N HCl (500 mL) for 1.5 hours
10. 10
    FiltrationThe organic layer was filtered
11. 11
    Lavagewashed with water, and brine

Mode opératoire

Thionyl chloride (13.2 mL, 181 mmol) was added (neat) to Example 2a, 6-(3-bromophenyl)hexanoic acid (16 g, 59.2 mmol) in a 1 L round-bottomed flask under a nitrogen atmosphere. The mixture was warmed to 60° C. for 2 h, excess reagent was removed in vacuo, and the residue was subjected to azeotropic conditions (benzene 3×). The acid chloride was dissolved in carbon disulfide (550 mL) and cannulated into a solution of aluminum trichloride (26.3 g, 198 mmol) in carbon disulfide (1315 mL) heated at reflux. The reaction was stirred 20 h, cooled, decanted, concentrated, and the resultant solids were stirred in diethyl ether/THF (1:1, 1 L), and 1N HCl (500 mL) for 1.5 hours. The organic layer was filtered, washed with water, and brine to give Example 3c, 2-bromo-7,8,9,10-tetrahydrobenzo[8]annulen-5(6H)-one 10.1 g (66%) as a colorless oil. 1H NMR (300 MHz, CDCl3) δ 7.55 (d, J=8.4 Hz, 1H), 7.38 (dd, J=8.4 Hz, 1.8 Hz, 1H), 7.33 (d, J=1.8 Hz, 1H), 2.99 (t, J=6.6 Hz, 2H), 2.89 (t, J=6.6 Hz, 2H), 1.85-1.73 (m, 4H), 1.52-1.44 (m, 2H). RT=2.8 minutes (condition 2); LRMS: Anal. Calcd. for C12H13BrO: 253.02. found: 253.15 (M+H).

Source