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also separated as a minor fraction from the column (Yield:
12.0 mg, 21%); H NMR (400 MHz; CDCl3): d=6.02 (s, 2H), 3.97 (s,
BODIPY 17
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A solution of 8-chloro-BODIPY 4a (56.4 mg, 0.2 mmol), p-carborane
thiol (45.6 mg, 0.24 mmol), and K2CO3 (41.5 mg, 3.0 mmol) in THF
(30 mL) was stirred at room temperature for 12 h or until the start-
ing material was consumed, The solvent was removed in vacuo
and the residue was taken up in CHCl3 and washed with water,
brine and then dried over anhydrous Na2SO4. The product was pu-
rified by column chromatography (eluted with CH2Cl2/hexane) to
3H), 2.89 (s, 3H), 2.51 (s, 6H), 2.37 ppm (s, 6H); 13C NMR (100 MHz;
CDCl3): d=159.95, 154.76, 138.33, 128.30, 119.56, 64.24, 49.12,
14.47, 13.76 ppm; 11B NMR (128 MHz; CDCl3): d=1.58 ppm; HRMS
(ESI): m/z calcd for C14H17BFN2O: 259.1418 [M+ÀOMe]; found:
259.1392. A small amount of the dimethoxyboron BODIPY 15 was
also isolated from the column, but in insufficient quantity to fully
characterize.
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give a red solid (80 mg, 92%); m.p. 150–1528C; H NMR (400 MHz;
CDCl3): d=6.06 (s, 2H), 2.95 (s, 2H), 2.51 (s, 3H), 2.49 (s, 3H), 2.17–
1.68 ppm (m, 11H); 13C NMR (100 MHz; CDCl3): d=156.14, 143.51,
136.84, 134.23, 122.50, 59.04, 46.04, 31.91, 16.91, 14.68 ppm; UV/
Vis (CH2Cl2): lmax (e)=529 nm (17000); HRMS (ESI): m/z calcd for
C16H26B11F2N2S: 437.2808; found: 437.3033.
BODIPY 14
8-Chloro-BODIPY 4a (56.4 mg, 0.2 mmol) was dissolved in THF
(30 mL) in an ice bath and sodium phenoxide (34.8 mg, 0.3 mmol)
was added; the mixture was stirred for 2 h at room temperature
and monitored by TLC analysis and spectrophotometry. The sol-
vent was removed in vacuo and the residue was taken up in CHCl3
and washed with water, brine and then dried over anhydrous
Na2SO4. The product was purified by silica-gel column chromatog-
raphy (eluted with CH2Cl2/hexane) to give an orange solid (55 mg,
General procedure for Stille coupling reactions
8-Chloro-BODIPY 4a (56.4 mg, 0.2 mmol), [Pd(PPh3)4] (10.0 mg, 5%
mmol) and organotin reagent (0.24–0.30 mmol) were added to
a round-bottomed flask. The flask was flushed with argon and
then anhydrous toluene was added, followed by injection of the
Stille reagents. The mixture was refluxed for 5 h, after which time
the reaction was complete; the toluene was then removed and the
residue was taken up in dichloromethane and washed with water,
brine and then dried over anhydrous Na2SO4. The crude product
was purified by silica-gel column chromatography (eluting with
CH2Cl2/hexane).
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81%); m.p. 188–1908C; H NMR (400 MHz; CDCl3): d=7.36–7.25 (m,
2H), 7.08–7.06 (m, 1H), 7.01–6.99 (m, 2H), 5.99 (s, 2H), 2.55 (s, 6H),
2.04 ppm (s, 6H); 13C NMR (100 MHz; CDCl3): d=157.52, 155.78,
151.59, 140.42, 130.08, 127.62, 122.84, 119.99, 114.70, 14.60,
14.14 ppm; UV/Vis (CH2Cl2): lmax (e)=491 nm (51300); HRMS (ESI):
m/z calcd for C19H20BF2N2O: 340.1668; found: 340.1662.
BODIPY 18: Yield: 60.1 mg, 93%; m.p. 165–1668C; 1H NMR
(400 MHz; CDCl3): d=7.49–7.47 (m, 3H), 7.29–7.27(m, 2H), 5.98 (s,
2H), 2.56 (s, 6H), 1.37 ppm (s, 6H); 13C NMR (100 MHz; CDCl3): d=
154.90, 142.19, 140.52, 131.14, 123.79, 121.11, 17.24, 14.55 ppm;
UV/Vis (CH2Cl2): lmax (e)=501 nm (57500); HRMS (ESI): m/z calcd for
C19H20BF2N2: 324.1718; found: 324.1717.
BODIPY 19: Yield: 50.7 mg, 97%; m.p. 245–2478C; 1H NMR
(400 MHz; CDCl3): d=6.05 (s, 2H), 2.56 (s, 6H), 2.51 (s, 6H),
2.40 ppm (s, 3H); 13C NMR (100 MHz; CDCl3): d=153.59, 141.43,
141.01, 132.06, 121.25, 17.31, 16.37, 14.43 ppm; UV/Vis (CH2Cl2):
lmax (e)=487 nm (66000); HRMS (ESI): m/z calcd for C14H18BF2N2:
262.1562; found: 262.1556.
BODIPY 20: Yield: 53.1 mg, 97%; m.p. 228–2308C; 1H NMR
(400 MHz; CDCl3): d=6.74 (dd, J=14.3, 9.1 Hz, 1H), 6.03 (s, 2H),
5.69 (dd, J=12.0, 2.2 Hz, 1H), 5.56 (d, J=17.5, 1.8 Hz, 1H), 2.53 (s,
6H), 2.23 ppm (s, 6H); 13C NMR (100 MHz; CDCl3): d=154.90,
142.19, 140.52, 131.14, 123.79, 121.11, 17.24, 14.55 ppm; UV/Vis
(CH2Cl2): lmax (e)=505 nm (46000); HRMS (ESI): m/z calcd for
C15H18BF2N2: 274.1562; found: 274.1557.
BODIPY 15
8-Chloro-BODIPY 4a (56.4 mg, 0.2 mmol) was dissolved in MeOH
(30 mL) and NaOMe (54.0 mg, 0.75 mmol) was added before the
solution was heated at reflux temperature, under argon for 12 h.
The solvent was removed and the residue was taken up in CHCl3
and washed with water, brine and then dried over anhydrous
Na2SO4. The product was separated by silica-gel chromatography
(eluted with MeOH/CH2Cl2). Yield: 38 mg, 65%; m.p. 93–958C;
1H NMR (400 MHz; CDCl3): d=6.01 (s, 2H), 3.97 (s, 3H), 2.86 (s, 6H),
2.48 (s, 6H), 2.41 ppm (s, 6H); 13C NMR (100 MHz; CDCl3): d=
159.92, 154.87, 137.38, 129.02, 119.33, 64.13, 49.04, 14.41,
13.81 ppm; 11B NMR (128 MHz; CDCl3): d=2.39 ppm; UV/Vis
(CH2Cl2): lmax (e)=487 nm (46800); HRMS (ESI): m/z calcd for
C16H23BN2NaO3: 324.173 [M+ +Na]; found: 324.1719. The monome-
thoxyboron-substituted BODIPY (see above) was also separated as
a minor fraction from the column (Yield: 9.3 mg, 16%).
BODIPY 21: Yield: 59.1 mg, 93%; m.p. 105–1078C; 1H NMR
(400 MHz; CDCl3): d=6.03 (s, 2H), 4.46 (d, J=2.9 Hz, 1H), 4.37 (d,
J=2.8 Hz, 1H), 3.89 (q, J=7.0 Hz, 2H), 2.52 (s, 6H), 2.23 (s, 6H),
1.39 ppm (t, J=7.0 Hz, 3H); 13C NMR (100 MHz; CDCl3): d=155.97,
153.56, 142.50, 134.98, 131.29, 88.11, 63.67, 14.65, 14.34 ppm; UV/
Vis (CH2Cl2): lmax (e)=513 nm (40700); HRMS (ESI): m/z calcd for
C17H22BF2N2O: 318.1824; found: 318.1817.
BODIPY 16
A solution of 8-chloro-BODIPY 4a (56.4 mg, 0.2 mmol), 2-mercapto-
benzothiozole (40.0 mg, 0.24 mmol), and K2CO3 (41.5 mg,
0.3 mmol) in THF (30 mL) was stirred at room temperature for 12 h
or until the starting material was almost completely consumed.
The solvent was removed in vacuo and the residue was taken up
in CHCl3 and washed with water, brine and then dried over anhy-
drous Na2SO4. The product was purified by silica-gel column chro-
matography (eluted with CH2Cl2/hexane). Yield: 46.1 mg, 56%; m.p.
208–2108C. 1H NMR (400 MHz; CDCl3): d=7.90 (dt, J=8.4, 0.9 Hz,
1H), 7.68 (m, 1H), 7.44 (ddd, J=8.4, 7.3, 1.3 Hz, 1H), 7.31 (ddd, J=
8.3, 7.3, 1.2 Hz, 1H), 6.10 (s, 2H), 2.58 (s, 6H), 2.46 ppm (s, 6H);
13C NMR (100 MHz; CDCl3): d=166.56, 158.25, 153.59, 144.75,
135.37, 134.42, 128.70, 126.46, 124.76, 123.07, 122.00, 121.08,
17.26, 14.97 ppm; UV/Vis (CH2Cl2): lmax (e)=539 nm (49000); HRMS
(ESI): m/z calcd for C20H18BFN3S: 394.1019 [MÀF]; found: 394.1010.
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BODIPY 22: Yield: 16.8 mg, 31%; m.p.>2608C; H NMR (400 MHz;
CDCl3): d=6.07 (s, 2H), 3.92 (s, 1H), 2.53 (s, 6H), 2.45 ppm (s, 6H);
13C NMR (100 MHz; CDCl3): d=155.07, 142.61, 133.28, 121.06,
118.92, 94.42, 79.19, 15.47, 14.63 ppm; UV/Vis (CH2Cl2): lmax (e)=
544 nm (37200); HRMS (ESI): m/z calcd for C15H16BF2N2: 272.1405;
found: 272.1380.
BODIPY 23: Yield: 21.7 mg, 71.1% (starting with 25 mg,
0.088 mmol of 4a); m.p.ꢁ2508C “(decomposed)”; 1H NMR
(400 MHz; CDCl3): d=6.06 (s, 2H), 2.52 (s, 6H), 2.46 (s, 6H),
Chem. Eur. J. 2014, 20, 1 – 12
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