ChemicalBook CAS DataBase List 4,4'-VINYLIDENEBIS(N,N-DIMETHYLANILINE)

4,4'-VINYLIDENEBIS(N,N-DIMETHYLANILINE) synthesis

9synthesis methods

Product Name:4,4'-VINYLIDENEBIS(N,N-DIMETHYLANILINE)
CAS Number:7478-69-5
Molecular formula:C18H22N2
Molecular Weight:266.38

1779-49-3
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$5.00/10g

90-94-8 Synthesis

90-94-8
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$29.00/100g

7478-69-5
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$60.00/100mg

Yield: 92%

Reaction Conditions:

Stage #1:Methyltriphenylphosphonium bromide with potassium tert-butylate in tetrahydrofuran at 0; for 2 h;Inert atmosphere;
Stage #2:bis(p-dimethylaminophenyl)methanone in tetrahydrofuran at 0;Reflux;Wittig Olefination;

Steps:

2.3 Synthesis of 1,1-bis(4-dimethylaminophenyl)ethylene
The synthesis of BDADPE was conducted by the classic Wittig reaction using 4,4′-bis(dimethylamino)benzophenone as substrate under an argon atmosphere (described in detail by Hirao [29]). Typically, methyltriphenylphosphonium bromide (45.58g, 127.6mmol) and freshly distilled THF (500mL) were added into a round bottom flask equipped with a reflux condenser and a magnetic bar. Potassium tert-butoxide (138.4mL of a 1.0M solution in THF, 138.4mmol) was then added dropwise to the reaction flask via constant pressure funnel. The reaction mixture was stirred for 2h at 0°C. Then the solution of 4,4′-bis(dimethylamino)benzophenone (21.4g, 79.75mmol) in dry THF (690mL) was dropped to the reaction mixture via constant pressure funnel at 0°C. The orange-brown reaction mixture was heated to reflux for 7h with stirring and then quenched with distilled water. The resultant mixture was extracted with ether three times. Such ethereal layer was washed with aqueous NaHCO₃ solution and saturated aqueous NaCl solution and then dried over MgSO₄. After filtration, the ethereal layer was poured into hexane to precipitate triphenylphosphine oxide. Flash column chromatography (petroleum ether/ethyl acetate 2:1 v/v) gave BDADPE in 92% yield (19.52g, 73.37mmol) and R_f=0.76. ¹H NMR (CDCl₃, 400MHz): δ 2.96 (s, 12H, 2×N(CH₃)₂), 5.19 (s, 2H, CH₂=C), 6.68-6.70 (d, 4H, aromatic proton ortho to N(CH₃)₂), 7.25-7.28 (d, 4H, aromatic proton meta to N(CH₃)₂).