S-(4-Isothiocyanatophenyl) 6-butylsulfanylthio-2-naphthoate 17
Quantities: compound 13 (0.64 g, 2.26 mmol), 4-isothiocyana-
tothiophenol9 (0.33 g, 1.98 mmol), 4-(N,N-dimethylamino)pyr-
idine (0.10 g, 0.8 mmol), N,N'-dicyclohexylcarbodiimide
(0.50 g, 2.31 mmol). The product was puri®ed by column
chromatography [petroleum fraction (bp 40±60 ³C)±dichloro-
methane 5 : 1] and was recrystallised (ethyl acetate) to give
white crystals which were dried in vacuo (P2O5). Yield 0.60 g
(73%). Transitions (³C) Cryst 90.7 SmA 94.3 N 136.1 Iso liq.
1H NMR (CDCl3) d: 0.97(3H, t), 1.53(2H, sextet), 1.74(2H,
quintet), 3.08(2H, t), 7.32(2H, d), 7.47(1H, dd), 7.54(2H, d),
7.67(1H, d), 7.79(1H, d), 7.87(1H, d), 7.98(1H, dd), 8.51(1H,
d). IR (KBr) nmax/cm21 850, 1125, 1210, 1400, 1480, 1615,
1670, 2050, 2080, 2920, 2940, 2960. MS m/z: 409(Mz),
243(100%), 215, 159, 115. UV lmax (cyclohexane),
235(40 640 dm3 mol21 cm21), 281(38 180), 337(27 090) nm.
Scheme 4 Reagents: 4a, CuCN; 4b, BBr3; 4c, (CF3SO2)2O; 4d, 4-
C4H9SC6H4B(OH)2, Pd(PPh3)4, Na2CO3.
Optical properties and calculated parameters. At T/TN±I
~0.7815: n,~1.95, n^~1.58, Dn~0.38, Da~39.86, S~0.66.
At 25 ³C: n,~1.97, n^~1.58, Dn~0.39, Da~40.28, S~0.68.
fraction (bp 40±60 ³C)±dichloromethane 1 : 1] and was recrys-
tallised (ethanol) to give white crystals which were dried in
vacuo (P2O5). Yield 3.00 g (86%). Transitions (³C) Cryst 93.2 N
114.8 Iso liq. 1H NMR (CDCl3) d: 0.96(3H, t), 1.50(2H, sextet),
1.70(2H, quintet), 3.00(2H, t), 7.46(2H, d), 7.63(2H, dd),
7.64(2H, d), 7.84(1H, dd), 7.96(1H, d), 8.05(1H, s), 8.24(1H, d).
IR (KBr) nmax/cm21 805, 895, 1095, 1395, 1460, 1485,
1590, 1620, 2220, 2860, 2920, 2950. MS m/z: 317(Mz),
261(100%), 227, 94, 59. UV lmax (cyclohexane)
223(32 890 dm3 mol21 cm21), 239(51 570), 325(28 760) nm.
6-Butylsulfanyldithio-2-naphthoic acid 18
Compound 18 was prepared in a similar way to that described
for the preparation of compound 15 in reference 9 except that
the formation of the Grignard reagent required heating under
re¯ux for 4 h. Quantities: compound 2 (3.71 g, 0.013 mol),
magnesium turnings (0.94 g, 0.039 mol), carbon disul®de
(1.09 g, 0.014 mol).
A purple solid was obtained. Yield 0.73 g (19%), mp 46±
47 ³C. 1H NMR (CDCl3) d: 0.97(3H, t), 1.53(2H, sextet),
1.73(2H, quintet), 3.11(2H, t), 7.43(1H, dd), 7.65(1H, d),
7.69(1H, d), 7.86(1H, d), 8.15(1H, dd), 8.55(1H, d). The
thioacid proton was not detected. IR (KBr) nmax/cm21 825,
870, 1090, 1180, 1460, 1610, 2460, 2870, 2920, 2950. MS m/z:
292(Mz), 259, 232, 203, 176(100%).
Optical properties and calculated parameters. At T/TN±I
~0.7815: n,~1.92, n^~1.56, Dn~0.36, Da~33.07, S~0.62.
At 25 ³C: n,~1.92, n^~1.56, Dn~0.36, Da~31.80, S~0.61.
2-(6-Butylsulfanyl-2-naphthyl)-5-cyanothiophene 28 (Scheme 5)
Compound 28 was prepared in a similar way to that described
for the preparation of compound 8 in reference 2. Quantities:
compound 3 (0.44 g, 1.69 mmol), 2-bromo-5-cyanothiophene
(27)3 (0.27 g, 1.44 mmol), tetrakis(triphenylphosphine)palla-
dium(0) (0.08 g, 0.069 mmol), sodium carbonate (1.5 cm3,
2.0 M, 3.00 mmol). The product was puri®ed by column
chromatography [petroleum fraction (bp 40±60 ³C)±dichloro-
methane 1 : 5] and was recrystallised (ethanol) to give a pale
green solid which was dried in vacuo (P2O5). Yield 0.10 g (22%).
Transitions (³C) Cryst 93.6 (N 73.2) Iso liq. 1H NMR (CDCl3)
d: 0.96(3H, t), 1.51(2H, sextet), 1.71(2H, quintet), 3.06(2H, t),
7.38(1H, d), 7.45(1H, dd), 7.63(1H, d), 7.65(1H, dd), 7.68(1H,
d), 7.78(2H, dd), 8.00(1H, d). IR (KBr) nmax/cm21 805, 810,
860, 1065, 1165, 1220, 1370, 1440, 1455, 1570, 1585, 1620, 2210,
2920, 2960, 3090. MS m/z: 323(Mz, 100%), 267, no other peaks
present. UV lmax (cyclohexane) 226(32 060 dm3 mol21 cm21),
245(22 120), 263(22 610), 284(21 740), 347(27 100) nm.
4-Cyanophenyl 6-butylsulfanyldithio-2-naphthoate 19
Compound 19 was prepared in a similar way to that described
for the preparation of compound 18 in reference 9. Quantities:
compound 18 (0.28 g, 0.96 mmol), 4-cyanothiophenol9 (0.10 g,
0.74 mmol), N,N'-dicyclohexylcarbodiimide (0.24 g, 1.11 mmol),
4-(N,N-dimethylamino)pyridine (0.05 g, 0.4 mmol). The pro-
duct was puri®ed by column chromatography [petroleum
fraction (bp 40±60 ³C)±dichloromethane 1 : 1] and was recrys-
tallised [petroleum fraction (bp 40±60 ³C)±ethyl acetate 1 : 1] to
give red crystals which were dried in vacuo (P2O5). Yield 0.05 g
1
(17%). Transitions (³C) Cryst 154.0 N 169.4 Iso liq. H NMR
(CDCl3) d: 0.97(3H, t), 1.52(2H, sextet), 1.74(2H, quintet),
3.09(2H, t), 7.45(1H, dd), 7.64(2H, d), 7.65(1H, d), 7.73(1H, d),
7.80(2H, d), 7.88(1H, d), 8.16(1H, dd), 8.62(1H, d). IR (®lm)
n
max/cm21 830, 890, 1060, 1180, 1210, 1455, 1485, 1610, 2240,
2920, 2950, 2960. MS m/z: 393(Mz), 259(100%), 203, 171, 158.
UV lmax (cyclohexane),
201(38 190 dm3 mol21 cm21),
242(36 730), 388(21 420) nm.
Optical properties and calculated parameters. At T/TN±I
~0.7815: n,~1.97, n^~1.58, Dn~0.38, Da~33.46, S~0.63.
At 25 ³C: n,~1.94, n^~1.57, Dn~0.37, Da~32.93, S~0.61.
Optical properties and calculated parameters. At T/TN±I
~0.7815: n,~2.10, n^~1.70, Dn~0.41, Da~66.85, S~0.39.
At 25 ³C: n,~2.18, n^~1.59, Dn~0.59, Da~67.28, S~0.59.
2-Bromo-5-nitrothiophene 30
A solution of nitric acid (24.0 g, 0.381 mol, 1.42 sp gr) in acetic
anhydride (50 cm3) at 0 ³C was added dropwise to a cooled
(0 ³C), rapidly stirred solution of 2-bromothiophene (24.8 g,
0.152 mol) in acetic anhydride (50 cm3). At the end of the
addition, the stirring was continued for 0.5 h and the nitration
mixture was refrigerated overnight (GLC and TLC analysis
revealed a complete reaction). The mixture was poured into
ice±water (400 cm3) and the precipitate was ®ltered off,
dissolved in ether (26200 cm3), and washed with water until
2-(4-Butylsulfanylphenyl)-6-cyanonaphthalene 24 (Scheme 4)
Compound 24 was prepared in a similar way to that described
for the preparation of compound 29 in reference 1. Quantities:
4-butylsulfanylphenylboronic acid2 (6.91 g, 0.033 mol), com-
pound 231 (3.42 g, 0.011 mol) tetrakis(triphenylphosphine)pal-
ladium(0) (0.70 g, 0.61 mmol), sodium carbonate (11.3 cm3,
2.0 M, 0.23 mol), lithium chloride (1.44 g, 0.034 mol). The
product was puri®ed by column chromatography [petroleum
2074
J. Mater. Chem., 2000, 10, 2069±2080