Journal of the American Chemical Society
ARTICLE
Preparation of Compound 10. K2CO3 (4.15 g, 30.0 mmol) was
added to a solution of fluorescein (3.32 g, 10.0 mmol) in DMF (20 mL)
at 25 °C under a nitrogen atmosphere, followed by allyl bromide (2.60
mL, 30 mmol). After it was stirred for 48 h at 25 °C, the reaction mixture
was poured onto H2O (500 mL). The resulting mixture was then
extracted with EtOAc (3 ꢀ 200 mL), and the combined extracts were
washed with H2O (3 ꢀ 500 mL) and brine (500 mL), dried over
Na2SO4, filtered, and evaporated under reduced pressure. The residue
was recrystallized from hexanes/EtOAc to afford compound 10 (3.17 g,
77%) as an orange solid. Data for 10: mp 153-155 °C; Rf = 0.34 (60%
EtOAc in hexanes); IR (KBr pellet) νmax 3054, 2986, 2932, 1727
(CdO), 1643 (CdO), 1595, 1517, 1481, 1256, 1211, 1106, 855, 759
cm-1; 1H NMR (300 MHz, CDCl3, 293 K, Figure S10) δ 8.27 (dd, J =
7.5, 1.5 Hz, 1H, Ar), 7.75 (ddd, J = 7.5, 7.5, 1.5 Hz, 1H, Ar), 7.68 (ddd, J =
7.5, 7.5, 1.5 Hz, 1H, Ar), 7.32 (dd, J = 7.5, 1.5 Hz, 1H, Ar), 6.96 (d, J = 2.4
Hz, 1H, Ar), 6.90 (d, J = 9.0 Hz, 1H, Ar), 6.87 (d, J = 9.6 Hz, 1H, Ar),
6.77 (dd, J = 9.0, 2.4 Hz, 1H, Ar), 6.56 (dd, J = 9.6, 1.8 Hz, 1H, Ar), 6.47
(d, J = 1.8 Hz, 1H, Ar), 6.07 (dddd, J = 17.4, 10.5, 5.4, 5.4 Hz, 1H,
CH2dCHCH2OAr), 5.60 (dddd, J = 17.4, 10.2, 6.0, 6.0 Hz, 1H,
ArCO2CH2CHdCH2), 5.46 (dd, J = 17.4, 1.2 Hz, 1H, HtransCHd
CHCH2OAr), 5.37 (dd, J = 10.5, 1.2 Hz, 1H, HCHcisdCHCH2OAr),
5.14-5.08 (m, 2H, ArCO2CH2CHdCH2), 4.66 (ddd, J = 5.4, 1.2, 1.2
Hz, 2H, CH2dCHCH2OAr), 4.48 (dddd, J = 12.9, 6.0, 1.2, 1.2 Hz, 1H,
ArCO2CHaHCHdCH2), 4.46 (dddd, J = 12.9, 6.0, 1.2, 1.2 Hz, 1H,
ArCO2CHHbCHdCH2) ppm; 13C NMR (75 MHz, CDCl3, 293 K,
Figure S11) δ 185.8, 165.2, 163.1, 159.1, 154.3, 150.2, 134.5, 132.9,
132.0, 131.4, 131.1, 130.67, 130.65, 130.4, 130.1, 129.9, 129.1, 119.3,
118.9, 117.9, 115.1, 113.9, 105.9, 101.3, 69.6, 66.2 ppm; HRMS (ESIþ)
m/z calcd for C26H21O5 [M]þ 413.1389, found 413.1373.
was heated in a 50 °C oil bath for 1 h. The reaction mixture was then
poured onto ice-cold H2O (10 mL), and the resulting mixture was
extracted with EtOAc (2 ꢀ 10 mL). The combined organic layers were
washed with brine (30 mL), dried over Na2SO4, filtered, and evaporated
under reduced pressure. The residue was purified by flash column
chromatography (10 f 30% EtOAc in hexanes) on silica gel (10 mL) to
afford compound 12 (70 mg, 97%) as an orange solid. Data for 12: mp
96-98 °C; Rf = 0.30 (40% EtOAc in hexanes); IR (KBr pellet) νmax
3304 (broad, O-H), 3045, 2921, 2858, 1610 (CdO), 1497, 1459, 1426,
1
1270, 1177, 1109, 1023, 846, 804, 725 cm-1; H NMR (400 MHz,
acetone-d6, 293 K, Figure S14) δ 7.47 (d, J = 7.6 Hz, 1H, Ar), 7.39 (dd, J
= 7.6, 7.6 Hz, 1H, Ar), 7.28 (dd, J = 7.6, 7.6 Hz, 1H, Ar), 6.96 (d, J = 8.8
Hz, 1H, Ar), 6.84 (d, J = 8.8 Hz, 1H, Ar), 6.83 (d, 6.82 J = 7.6 Hz, 1H,
Ar), (d, J = 2.4 Hz, 1H, Ar), 6.75 (dd, J = 8.8 2.4 Hz, 1H, Ar), 6.67 (d, J =
2.4 Hz, 1H, Ar), 6.60-6.55 (m, 2H, Ar and CH3CHdCHOAr), 5.30 (s,
2H, ArCH2OH), 4.96 (dq, J = 6.8, 6.8 Hz, 1H, CH3CHdCHOAr), 1.68
(dd, J = 6.8, 1.6 Hz, 3H, CH3CHdCHOAr) ppm; 13C NMR (100 MHz,
acetone-d6, 293 K, Figure S15) δ 159.2, 158.7, 152.12, 152.07, 146.7,
141.4, 140.0, 131.2, 131.0, 129.1, 128.9, 124.3, 121.9, 120.7, 117.6, 112.9,
112.7, 108.7, 103.5, 102.8, 84.0, 72.9, 9.6 ppm; HRMS (ESIþ) m/z calcd
for C23H18O4Na [M þ Na]þ 381.1103, found 381.1083.
Conversion of Compound 12 to Compound 13. HgCl2 (18
mg, 67 μmol) was added to a solution of compound 12 (24 mg, 67
μmol) in a 1/9 DMSO/pH 4 buffer (26 mL) mixture. The resulting
mixture was stirred at 25 °C for 1 h and extracted with EtOAc (2 ꢀ 20
mL). The combined organic layers were washed with brine (2 ꢀ 50 mL),
dried over Na2SO4, filtered, and evaporated under reduced pressure.
The residue was purified by flash column chromatography (10 f 70%
EtOAc in hexanes) on silica gel (10 mL) to afford compound 13 (15 mg,
72%) as an orange solid. Data for 13: mp >200 °C; Rf = 0.32 (50%
EtOAc in hexanes); IR (KBr pellet) νmax 3430 (broad, O-H), 2869,
2600, 1602 (CdO), 1455, 1379, 1309, 1241, 1207, 1117, 860, 757
cm-1; 1H NMR (300 MHz, acetone-d6, 293 K, Figure S16) δ 7.45 (d, J =
7.5 Hz, 1H, Ar), 7.34 (dd, J = 7.5, 7.5 Hz, 1H, Ar), 7.27 (dd, J = 7.5, 7.5
Hz, 1H, Ar), 6.83 (d, J = 7.5 Hz, 1H, Ar) 6.81 (d, J = 8.4 Hz, 2H, Ar), 6.64
(d, J = 2.4 Hz, 2H, Ar), 6.56 (dd, J = 8.4, 2.4 Hz, 2H, Ar), 5.26 (s, 2H,
ArCH2OH) ppm; 13C NMR (75 MHz, acetone-d6, 293 K, Figure S17) δ
159.0, 152.3, 146.9, 140.2, 131.0, 129.1, 128.8, 124.4, 121.8, 117.9, 112.6,
102.8, 84.2, 72.6 ppm; HRMS (EIþ) m/z calcd for C20H15O4 [M]þ
319.0970, found 319.0999.
Sample Preparations. Mercury standard solution (20 ppm in 5%
HNO3) was purchased from the RICCA Chemical Co. (Arlington, TX)
and used as received. The other mercury standard solution (10 000 ppm
in 2% HNO3) was purchased from Ultra Scientific (North Kingstown,
Rhode Island) and used as received. OmniTrace Ultra High Purity Acid
HNO3 (Hg < 10 ppt) was purchased from EMD (item number NX0408,
lot number 48157) and used as received. ARISTAR ULTRA water was
purchased from VWR (catalog number 7732-18-5) and used as received.
AgNO3 was purchased from EMD and used as received. River water was
collected from the Allegheny River on Jan 29, 2008. The pH 3 buffer
solution was made from a commercial pH 4 buffer (50 mM) and a pure
HNO3 solution.
Preparation of Compound 11. A solution of DIBALH (9.6 mL,
1.0 M in CH2Cl2) was added dropwise to a solution of compound 10
(0.83 g, 2.0 mmol) in CH2Cl2 (7.0 mL) over 15 min at -78 °C under a
nitrogen atmosphere. The resulting solution was stirred at the same
temperature for 10 min and then warmed to 25 °C. After stirring at the
same temperature for 2 h, Et2O (5.0 mL) was added to the resulting
solution at 0 °C with stirring, and then saturated aqueous NH4Cl
(3.5 mL) was added dropwise to the mixture at the same temperature.
This mixture was warmed to 25 °C again and stirred for 1 h. The reaction
mixture was then diluted with Et2O (5.0 mL), and DDQ (0.45 g,
2.2 mmol) was added slowly to this mixture at 0 °C. After being stirred
for 1 h at 25 °C, the mixture was filtered through a pad of Celite, and the
pad was rinsed with EtOAc. The filtrate was dried over Na2SO4, filtered,
and evaporated under reduced pressure. The residue was purified by
flash column chromatography (10 f 30% EtOAc in hexanes) on silica
gel (180 mL) to afford compound 11 (701 mg, 98%) as a pale yellow
solid. Data for 11: mp 144-146 °C; Rf = 0.32 (30% EtOAc in hexanes);
IR (KBr pellet) νmax 3228 (broad, O-H), 2921, 2852, 1616 (CdO),
1
1501, 1517, 1456, 1430, 1335, 1224, 1180, 1003, 841, 759 cm-1; H
NMR (300 MHz, acetone-d6, 293 K, Figure S12) δ 7.44 (d, J = 7.5 Hz,
1H, Ar), 7.37 (dd, J = 7.5, 7.5 Hz, 1H, Ar), 7.26 (dd, J = 7.5, 7.5 Hz, 1H,
Ar), 6.89 (d, J = 8.7 Hz, 1H, Ar), 6.84 (d, J = 7.5 Hz, 1H, Ar), 6.83 (d, J =
8.7 Hz, 1H, Ar), 6.76 (d, J = 2.4 Hz, 1H, Ar), 6.67 (d, J = 2.4 Hz, 1H, Ar),
6.66 (dd, J = 8.7, 2.4 Hz, 1H, Ar), 6.58 (dd, J = 8.7, 2.4 Hz, 1H, Ar), 6.07
(dddd,, J = 17.4, 10.5, 5.4, 5.4 Hz, 1H, CH2dCHCH2OAr), 5.42 (dd, J =
17.4, 1.2 Hz, 1H, HtransCHdCHCH2OAr), 5.28 (s, 2H, ArCH2OH),
5.24 (dd, J = 10.5, 1.2 Hz, 1H, HCHcisdCHCH2OAr), 4.61 (ddd, J = 5.4,
1.2, 1.2 Hz, 2H, CH2dCHCH2OAr) ppm; 13C NMR (75 MHz,
acetone-d6, 293 K, Figure S13) δ 160.2, 159.0, 152.2, 152.1, 146.7,
140.1, 134.5, 131.0, 130.9, 129.1, 128.8, 124.3, 121.9, 118.9, 117.74,
117.67, 112.7, 112.3, 107.8, 101.9, 84.1, 72.7, 69.5 ppm; HRMS (ESIþ)
m/z calcd for C23H18O4Na [M þ Na]þ 381.1103, found 381.1072.
Preparation of Compound 12. KOtBu (56 mg, 0.44 mmol) was
added to a solution of compound 11 (72 mg, 0.20 mmol) in DMSO (1.7
mL) at 25 °C under a nitrogen atmosphere, and the resulting solution
Metal Solutions (1.0 mM). AuCl3, BaCl2, NiCl2, CrCl3, Pb-
(NO3)2, NaCl, MnCl2 4H2O, MgCl2, CoCl2, HgCl2, AgNO3, ZnCl2,
3
LiCl, CuCl2 2H2O, and CaCl2 were dissolved in H2O. FeCl3, CdCl2
3
3
2.5H2O, KCl, Rh(PPh3)3, and RuCl3 were dissolved in MeOH. PtCl2
was dissolved in MeOH/acetone (1/1). Pd standard solution (High-
Purity Standards, Cat. No. 100038-1) was diluted with 1% HNO3. The
resulting solution was used as the Pd solution.
Fluorescence Measurement. All samples were incubated at 25
°C, and the pH values of the solutions were adjusted to an appropriate
pH range (pH >5 for 1, pH >8 for 13) by the addition of 1.23 M phos-
phate pH 7 buffer (for 1, 4.0% of the total volume of a reaction solution)
or a 1:5 mixture of 1.23 M phosphate pH 7 buffer and 500 mM borate
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dx.doi.org/10.1021/ja108028m |J. Am. Chem. Soc. 2011, 133, 2556–2566