J. H. Malpert et al. / Tetrahedron 57 (2001) 967±974
973
generally produced colorless crystals although sometimes
the procedure has to be repeated. The compounds are
isolated as white or slightly colored crystals.
nitrile (8A). Compound 7A (1.6 g, 5.1 mmol) was dissolved
in 100 mL of anhydrous THF. Triethylamine (7.2 mL,
51 mmol) was added, and then a solution of trityl bromide
(5.3 g, 16.1 mmol) in 20 mL of THF was added dropwise.
The reaction mixture was stirred overnight. The THF was
partially evaporated until about 40 mL was left, and the
precipitate of triethylammonium bromide was ®ltered.
Hexanes were added to the mother liquor, and the solid
that precipitated was puri®ed by cold recrystallization
from methylene chloride±methanol. A second recrystalli-
zation from methylene chloride±hexanes provides 4.2 g of
7.3.1.
Bis(40,400-N,N-dimethylaminophenyl)-2-¯uoro-
phenyl acetonitrile (2A). White crystals. Mp200±
2038C. 1H NMR (CDCl3): d 2.96 (s, 12H), 6.68 (d,
J8.8 Hz, 4H), 6.75±6.79 (m, 1H), 7.00±7.14 (m, 6H),
7.26±7.34 (m, 1H). 13C NMR (CDCl3): d 40.3, 51.8,
112.0, 116.4 (d, J21.9 Hz), 122.6, 123.8 (d, J3.7 Hz),
126.6, 129.0, 129.3, 130.0 (d, J9.1 Hz), 130.3, 149.8,
160.5 (d, J251.1 Hz). IR (NaCl): 2890, 2240, 1608,
1519 cm21. MS (EI) m/z 373, 278. Elem. Anal. Calculated
for C24H24FN3: C, 77.18; H, 6.48; N, 11.25. Found C, 77.05;
H, 6.52; N, 11.15. TLC (hexanes/ethyl acetate 10:1 on
alumina) Rf0.26.
1
pure material. H NMR (CDCl3): d 4.95 (s, 3H), 6.17 (d,
J8.4 Hz, 6H), 6.43 (d, J8.4 Hz, 6H), 7.13±7.33 (m, 45
H). 13C NMR (CDCl3): d 54.7, 71.6, 115.8, 124.4, 126.7,
127.8, 128.4, 129.0, 129.8, 145.2, 145.6. IR (NaCl): 3405,
3083, 1608, 1509, 699.
7.3.2. Bis(40,400-N,N-dimethylaminophenyl)-3-¯uorophe-
nyl acetonitrile (3A). Pale blue crystals. Mp160±1638C.
1H NMR (CDCl3): d 2.96 (s, 12H), 6.66 (d, J8.8 Hz, 4H),
6.89±7.13 (m, 6H), 7.25±7.32 (m, 2H). 13C NMR (CDCl3):
d 40.4, 55.6, 112.0, 114.6 (d, J21.8 Hz), 116.0 (d,
J23.7 Hz), 123.7, 124.4 (d, J2.8 Hz), 127.6, 129.4,
129.8 (d, J8.1 Hz), 144.2, 149.8, 162.7 (d, J245.7 Hz).
IR (NaCl): 2890, 2234, 1610, 1519, 808 cm21. MS (EI) m/z
373, 278. Elem. Anal. Calculated for C24H24FN3: C, 77.18;
H, 6.48; N, 11.25. Found C, 77.19; H, 6.57; N, 11.17. TLC
(hexanes/ethyl acetate 10:1 on alumina) Rf0.33.
7.4. Victoria Blue Leuconitrile (9A)
This compound was synthesized via a metathesis reaction
using the commercial dye and potassium cyanide
(CAUTION: KCN is a highly toxic material) in ethanol.
Spectral characteristics matched those found in the litera-
ture.8
7.4.1. Bis(40,400-dimethylaminophenyl)-(2-methylindol-3-
yl)methane (10D). This compound was made via a slight
modi®cation of the following literature procedure.12 A solu-
tion of dilute HCl (1 mL of concentrated acid in 25 mL of
water) was added dropwise to a solution of 4,40-bis-
(dimethylamino)benzhydrol (2.01 g, 15.34 mmol) and
2-methylindole (4.15 g, 15.34 mmol) in 125 mL of metha-
nol. This solution was re¯uxed for 90 min and then
quenched with 1N NaOH. The precipitate that formed was
®ltered to provide 5.71 g (97% yield) of a slightly purple
solid. 1H NMR (CDCl3): d 2.20 (s, 3H), 2.90 (s, 12H), 5.58
(s, 1H), 6.67 (d, J8.6 Hz, 4H), 6.88 (t, J 7.2 Hz, 1H),
7.00±7.26 (m, 7H), 7.73 (bs, 1H).
7.3.3.
Bis(40,400-N,N-dimethylaminophenyl)-4-¯uoro-
phenyl acetonitrile (4A). White crystals. Mp174±
1
1758C. H NMR (CDCl3): d 2.96 (s, 12H), 6.66 (d, J
9.2 Hz, 4H), 6.96±7.06 (m, 6H), 7.19±7.26 (m, 2H). 13C
NMR (CDCl3): d 40.4, 55.3, 112.0, 115.2 (d, J21.8 Hz),
124.1, 128.0, 129.4, 130.4 (d, J7.3 Hz), 137.5, 149.8,
162.0 (d, J246.6 Hz). IR (NaCl): 2805, 2230, 1609,
1516, 814 cm21. MS (EI) m/z 373, 278, 253. Elem. Anal.
Calculated for C24H24FN3: C, 77.18; H, 6.48; N, 11.25.
Found C, 77.13; H, 6.54; N, 11.09. TLC (hexanes/ethyl
acetate 2:1 on alumina) Rf0.57.
7.4.2. Bis(4-dimethylaminophenyl)-(2-methylindol-3-yl)
acetonitrile (10A). The triarylmethane 10D (1.01 g,
2.6 mmol) was placed in 20 mL of ethanol. After warming
did not dissolve the solid, chloroform was added dropwise
until a homogeneous solution was obtained. The 2,3-
dichloro-5,6-dicyano-1,4-benzoquinone (0.590 g, 2.6 mmol)
was added slowly, and a vigorous reaction ensued. A slight
excess of the DDQ was added to ensure complete con-
version of starting material. The KCN (1.69 g, 26.0 mmol)
(CAUTION: KCN is a highly toxic material) was added as
a solution in water (5 mL). Dichloromethane was added,
and this solution washed with aqueous NaHCO3 (2£
50 mL), 0.1 M HCl (2£50 mL) and brine. The solution
was concentrated and ®ltered through a small plug of
alumina (3:1 hexanes: ethyl acetate) to provide the product.
Recrystallization from ethanol provided 0.250 g (25%) of
7.3.4. Bis(40,400-N,N-dimethylaminophenyl)-2,3,4,5,6-penta-
¯uorophenyl acetonitrile (5A). White crystals. Mp175±
1
1768C. H NMR (CDCl3): d 2.97 (s, 12H), 6.67 (d, J
8.8 Hz, 4H), 7.30 (d, J8.8 Hz, 4H). 13C NMR (CDCl3): d
42.3, 52.2, 114.1, 117.0±118.0 (m, 1C), 122.9, 126.8, 130.4,
137.0±150.0 (m, 3C), 152.2. IR (NaCl): 2924, 2236, 1611,
1521, 1488 cm21. MS (EI) m/z 445, 278, 138. Elem. Anal.
Calculated for C24H20F5N3: C, 64.71; H, 4.53; N, 9.44.
Found C, 65.69; H, 5.23; N, 8.63. TLC (hexanes/ethyl
acetate 5:1 on alumina) Rf0.50.
7.3.5. Tris(40,400,4000-dimethylaminophenyl) acetonitrile
(6A). This compound synthesized via a metathesis reaction
using the commercial dye and potassium cyanide
(CAUTION: KCN is a highly toxic material) in ethanol.
Spectral characteristics matched those found in the literature.8
1
product. H NMR (CDCl3): d 1.97 (s, 3H), 2.96 (s, 12H),
6.57±6.69 (m, 5H), 7.02±7.28 (m, 6H), 7.92 (bs, 1H). MS
(EI) m/z 408.
7.3.6. Tris(40,400,4000-aminophenyl) acetonitrile (7A).
Same as 6A. H NMR (CD3CN): d 4.23 (bs, 6H), 6.57±
6.63 (m, 6H), 6.81±6.87 (m, 6H).
1
7.4.3. Bis(40,400-dimethylaminophenyl)-(1-butyl-2-methyl-
indol-3-yl)methane (11D). Under an inert atmosphere, the
triarylmethane 10D (0.345 g, 0.900 mmol) was dissolved in
10 mL of dry tetrahydrofuran. The solution was cooled to
7.3.7. Trityl protected tris(40,400,4000-aminophenyl) aceto-