demonstrated that the characteristics of the well preorganized
fluororeceptors are promising for the development of chemical
sensors for a specific anion.
To a refluxing suspension of the above imide in EtOH
(20 mL) was added hydrazine monohydrate (1.0 g, 20 mmol),
and the mixture was refluxed again for 30 min. After cooling,
6 M aqueous HCl was added to acidify the mixture and it was
refluxed for 30 min. The mixture was poured into aqueous
NaOH and extracted three times with CHCl3. The combined
organic phase was washed with brine, dried over anhydrous
Na2SO4, filtered, and concentrated to leave triamine 7 (640 mg,
64% for two steps) as a white solid. The product was used for
the following reaction without further purification. δH (CDCl3)
0.98 (9H, t, J = 7.0, CH3), 1.36 (6H, s, NH2), 1.45–1.51 (12H, m,
CH2CH2CH3), 2.71–2.77 (6H, m, ArCH2CH2), 3.84 (6H, s,
ArCH2NH2).
Experimental
1H- and 13C-NMR spectra were recorded on a JEOL JNM-
GSX 270 spectrometer in CDCl3 or DMSO-d6. Coupling
constants are given in Hz, and all chemical shifts are reported
relative to an internal standard of tetramethylsilane or using
the residual solvent peak as a standard. Abbreviations Ar, An,
and Py represent aromatic, anthryl, and pyrenyl, respectively.
Melting points were determined on a BÜCHI B-545 apparatus
and are uncorrected. All moisture-sensitive reactions were
carried out under an atmosphere of nitrogen. 1,3,5-Trichloro-
benzene, chloromethyl methyl ether, 1-bromobutane, hydrazine
monohydrate, 9-(chloromethyl)anthracene, and 1-aminopyrene
were purchased from Tokyo Kasei Kogyo Co. (Tokyo, Japan).
[1,3-Bis(diphenylphosphino)propane]nickel() chloride [NiCl2-
(DPPP)] and phthalimidopotassium were purchased from
Kanto Chemical Co. (Tokyo, Japan). Solvents were dried (dry-
ing agent in parentheses) and distilled prior to use: ether
(LiAlH4), THF (sodium ketyl benzophenone), DMF (CaH2).
9-(Isothiocyanatomethyl)anthracene. 9-(Aminomethyl)anthra-
cene13 was prepared from 9-(chloromethyl)anthracene by the
Gabriel reaction as described for the preparation of triamine 7.
To a solution of amine (638 mg, 3.1 mmol) in THF (10 mL) was
added NaOH (246 mg, 6.2 mmol) dissolved in a small amount
of water, and then CS2 (2.35 g, 30.8 mmol) was slowly added.
The mixture was stirred for 1 h at room temperature. 30% H2O2
was added dropwise with cooling in an ice-bath, and the mix-
ture was acidified with 10% HCl. The mixture was diluted with
water and extracted three times with CHCl3. The combined
organic phase was washed with brine, dried over anhydrous
Na2SO4, filtered, and concentrated. The crude product was
purified by chromatography on silica gel (hexane–EtOAc, 9 : 1)
to give the desired isothiocyanate (506 mg, 66%) as a yellow
solid. δH (CDCl3) 5.59 (2H, s, AnCH2NCS), 7.50–7.55 (2H, m,
An), 7.60–7.66 (2H, m, An), 8.06 (2H, dd, J = 0.7, 8.1, An), 8.23
(2H, d, J = 8.4, An), 8.53 (1H, s, An).
Preparation of fluororeceptors
1,3,5-Tributyl-2,4,6-tris(chloromethyl)benzene 6. To a stirred
suspension of 1,3,5-trichlorobenzene (25.0 g, 0.138 mol) and
NiCl2(DPPP) (753 mg, 1.4 mmol) in ether (150 mL) was added
a solution of 1-butylmagnesium bromide prepared from
1-bromobutane (113 g, 0.825 mol) and magnesium (20.1 g,
0.827 mol) in ether (200 mL) over a period of 20 min at 0 ЊC.
The reaction mixture was allowed to warm to room temper-
ature and stirred for 40 min; during that period, an exothermic
reaction started. The mixture was then refluxed for 8 h, cooled
in an ice-bath, and hydrolyzed with 10% aqueous HCl. The
organic layer was separated and the aqueous layer was
extracted twice with ether. The combined organic phase was
washed with saturated aqueous NaHCO3 and brine, dried over
anhydrous Na2SO4, filtered, and concentrated to leave a brown
oil (31.4 g).
To a solution of the above crude 1,3,5-tributylbenzene in
chloromethyl methyl ether (200 mL) was added concentrated
sulfuric acid (10 mL), and the mixture was refluxed for 18 h.
During that period, chloromethyl methyl ether (100 mL) and
concentrated sulfuric acid (5 mL) were added twice. The reac-
tion mixture was poured into ice–water and extracted three
times with ethyl acetate. The combined extract was washed with
saturated aqueous NaHCO3 and brine, dried over anhydrous
Na2SO4, filtered, and concentrated. The product was dissolved
in CH2Cl2 and hexane was added. The resulting precipitate was
separated and dried to give the trichloride 6 (17.5 g, 35%) as a
white solid. Mp 129–130 ЊC; δH (CDCl3) 1.04 (9H, t, J = 7.1,
CH3), 1.51–1.62 (12H, m, CH2CH2CH3), 2.86 (6H, m,
ArCH2CH2), 4.70 (6H, s, ArCH2Cl).
1-(Isothiocyanato)pyrene14. This compound was prepared
from 1-aminopyrene by the same procedure.
1,3,5-Tributyl-2,4,6-tris[(NЈ-(1-pyrenyl)thioureido)methyl]-
benzene 1. Into a nitrogen-purged flask a solution of triamine 7
(25 mg, 0.075 mmol) in CHCl3 (5 mL) was added followed by a
solution of 1-(isothiocyanato)pyrene (78 mg, 0.30 mmol) in
CHCl3 (5 mL). The mixture was refluxed for 6 h and con-
centrated to remove the solvent. The product was purified by
recrystallization from 1,1,2,2-tetrachloroethane to afford recep-
tor 1 (13 mg, 16%) as colorless needles. Mp 180–182 ЊC;
δH (DMSO-d6) 1.00 (9H, t, J = 6.4, CH3), 1.57 (12H, br,
CH2CH2CH3), 2.86 (6H, br, ArCH2CH2), 4.87 (6H, br,
ArCH2NH), 7.74 (3H, br, CH2NH), 8.04–8.33 (27H, m, Py),
9.86 (3H, br, PyNH); δC (DMSO-d6) 13.9 (CH3), 23.1, 29.8, 34.4
and 43.0 (CH2), 121.9, 122.0, 123.8, 124.4, 124.6, 125.0, 125.3,
125.8, 126.4, 126.8, 127.1, 127.3, 128.8, 130.4, 130.7, 132.3,
133.0 and 142.9 (ArC and PyC), 182.0 (S᎐C) (Found: C, 77.64;
᎐
H, 5.94; N, 7.47; S, 8.61. Calc. for C72H66N6S3: C, 77.80;
H, 5.98; N, 7.56; S, 8.65%). Receptors 2 and 4 were prepared
similarly.
1,3,5-Tris[(NЈ-(9-anthrylmethyl)thioureido)methyl]-2,4,6-tri-
butylbenzene 2. This compound was obtained as a yellow solid
after trituration with ether in 50% yield. Mp 253–255 ЊC;
δH (DMSO-d6) 0.80 (9H, t, J = 7.0, CH3), 1.34–1.39 (12H, m,
CH2CH2CH3), 2.50 (ArCH2CH2 protons overlapped the
residual solvent peak), 4.56 (6H, br s, ArCH2NH), 5.58 (6H, d,
J = 4.0, AnCH2NH), 6.92 (3H, br s, ArCH2NH), 7.49–7.56
(15H, m, An), 8.09–8.12 (6H, m, An), 8.32–8.35 (6H, m, An),
8.61 (3H, s, AnCH2NH); δC (DMSO-d6) 13.7 (CH3), 22.8, 29.4,
34.2 and 42.3 (CH2), 124.2, 125.2, 126.4, 127.5, 128.9, 129.8,
1,3,5-Tris(aminomethyl)-2,4,6-tributylbenzene 7. Phthalimido-
potassium (2.22 g, 12 mmol) was added to a solution of 6
(1.18 g, 3.0 mmol) in DMF (10 mL). The reaction mixture was
stirred at 60 ЊC for 3 h and then cooled to room temperature.
The mixture was poured into 0.5 M aqueous NaOH and
extracted three times with CHCl3. The combined extract was
washed with brine, dried over anhydrous Na2SO4, filtered, and
concentrated to leave an oily solid. To the residue was added
CH2Cl2 (3 mL) followed by hexane (20 mL). The resulting solid
was filtered, washed with ether, and dried to afford 1,3,5-
tributyl-2,4,6-tris(phthalimidomethyl)benzene (1.39 g) as a
white solid. δH (CDCl3) 0.63 (9H, t, J = 7.0, CH3), 1.16–1.64
(12H, m, CH2CH2CH3), 2.98–3.04 (6H, m, ArCH2CH2), 4.92
(6H, s, ArCH2N), 7.66–7.82 (12H, m, Ar).
131.0, 132.3, and 142.0 (ArC and AnC), 181.6 (S᎐C) (Found: C,
᎐
76.52; H, 6.58; N, 7.63; S, 8.91. Calc. for C69H72N6S3: C, 76.63;
H, 6.71; N, 7.77; S, 8.89%).
9-[(NЈ-butylthioureido)methyl]anthracene 4. This compound
was obtained as a yellow solid after column chromatography
2312
J. Chem. Soc., Perkin Trans. 2, 2001, 2309–2313