Iodine → 1,3-Bis(triethoxysilyl)benzene

HRID 484188Notes

Reaction equation

HRID 484188 reaction equation
[Mg].C(O[Si:5]([O:12][CH2:13][CH3:14])([O:9][CH2:10][CH3:11])[O:6][CH2:7][CH3:8])C.II.Br[C:18]1[CH:23]=[CH:22][CH:21]=[C:20](Br)[CH:19]=1.Br[C:26]1[CH:31]=CC=CC=1Br>O1CCCC1>[CH2:13]([O:12][Si:5]([O:6][CH2:7][CH3:8])([O:9][CH2:10][CH3:11])[C:18]1[CH:23]=[CH:22][CH:21]=[C:20]([Si:5]([O:12][CH2:31][CH3:26])([O:9][CH2:10][CH3:11])[O:6][CH2:7][CH3:8])[CH:19]=1)[CH3:14]

Participants

7

Reactant 5

HCID 807IodineHCID 6517TetraethoxysilaneHCID 79271,3-DibromobenzeneHCID 114141,2-DibromobenzeneHCID 5462224Magnesium2×

Product 1

HCID 116037721,3-Bis(triethoxysilyl)benzene

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

Magnesium chips (28.0 g, 1.15 mol) and freshly distilled tetraethoxysilane (450 mL, 2 mol) in tetrahydrofuran (750 mL) were placed under nitrogen in a 2 L 3-neck flask equipped with a magnetic stir bar, a condenser, and an additional funnel. A small crystal of iodine was added in order to activate the magnesium. A solution of 1,3-dibromobenzene (100.0 g, 0.424 mol) in tetrahydrofuran (250 mL) was added slowly. When ca. 25 mL of the dibromide had been added, the addition was stopped and stirring was continued until a mildly exothermic reaction began (usually within 20-30 minutes). The addition of dibromobenzene was continued and held at such a rate as to maintain the solution at reflux. After the addition was complete, the reaction mixture was stirred for two additional hours. The resulting brown solution was filtered from the remaining magnesium metal, and the tetrahydrofuran was removed by evacuation. The brown residue was extracted with dry hexane (500 mL), and combined extracts were concentrated in vacuo. Unreacted tetraethyl orthosilicate was removed in vacuo (103 torr), leaving a tea-brown oil. Two distillations gave the product as a clear, colorless oil (0.1 mm Hg, 126-128° C., 58.0 g., 34%). Anal. Calcd for C18H34O6Si2 : C, 53.7; H, 8.51. Found: C, 54.1; H, 8.59. IR (Neat, Csl, cm-1): 3060 W, 2970 s, 2920 s, 2880 s, 2730 w, 1577 m, 1478 w, 1439 m, 1390 s, 1365 m, 1290 m, 1160 s, 1090 vs, 958 s, B05 s, 770 s, 715 m, 705 m, 670 m, 485 s. 1H NMR (benzene-d6, 22° C., 300 MHz ): δ 1.15 (t, J=7.1 Hz, 18 H, OCH2CH3), 3.91 (q, J=7.1 Hz, 12 H, OCH2CH3), 7.30 (t, J=7.2 Hz, 1 H, C6H4), 7.89 (d, J=7.2 Hz, 2 H, C6H4), 8.37 (s, 1 H, C6H4). 13C{1H}NMR (benzene-d6, 22° C., 75.5 MHz): δ 18.43 (PHC2CH3), 58.89 (OCH2CH3), 127.59, 131.52, 137.06, 141.70 (C6H4)

Workup

  1. customequipped with a magnetic stir bar, a condenser, and an additional funnel
  2. additionthe addition
  3. customwas continued until a mildly exothermic reaction
  4. customusually within 20-30 minutes
  5. temperatureto maintain the solution
  6. temperatureat reflux
  7. additionAfter the addition
  8. stirringthe reaction mixture was stirred for two additional hours
  9. filtrationThe resulting brown solution was filtered from the remaining magnesium metal
  10. customthe tetrahydrofuran was removed by evacuation
  11. extractionThe brown residue was extracted with dry hexane (500 mL)
  12. concentrationwere concentrated in vacuo
  13. customwas removed in vacuo (103 torr)
  14. customleaving a tea-brown oil
  15. customTwo distillations gave the product as a clear, colorless oil (0.1 mm Hg, 126-128° C., 58.0 g., 34%)
  16. custom715 m, 705 m, 670 m, 485 s

Sources & evidence

ORD record
ord-f9a8ad34e1ed489c9a66cca8e2f1230a
Source dataset
uspto-grants-1993_07
Patent number
US05229481

Reaction notes

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