50.8, 13.9; MS (ESI): m/z 382 {100%, [M + H]+}; HRMS (ESI):
m/z calcd for C19H28NO7 [M + H]+: 382.1860, found: 382.1853.
H, ArH and C CH), 7.00 (d, J = 8.4 Hz, 2 H, ArH), 6.90 (t, J =
5.6 Hz, 2 H, NH), 6.76 (d, J = 8.8 Hz, 2 H, ArH), 6.57 (s, 1 H,
pyrrole-H), 5.97 (s, 1 H, pyrrole-H), 4.17 (t, J = 4.8 Hz, 2 H, CH2),
3.94 (s, 4 H, CH2), 3.89 (t, J = 4.4 Hz, 2 H, CH2), 3.75–3.77 (m, 2
H, CH2), 3.68–3.71 (m, 6 H, CH2), 3.65–3.67 (m, 6 H, CH2), 3.60
(t, J = 4.8 Hz, 4 H, CH2), 3.55–3.57 (m, 2 H, CH2), 3.38 (s, 3 H,
CH3), 3.30–3.34 (m, 4 H, CH2), 2.55 (s, 3 H, CH3), 1.45 (s, 3 H,
Synthesis of monostyryl BODIPY 5
A mixture of BODIPY 1 (30 mg, 62 mmol), benzaldehyde 3
(100 mg, 0.26 mmol), glacial acetic acid (52 mL), and piperidine
(43 mL) in toluene (10 mL) was heated to reflux. The water formed
during the reaction was removed azeotropically with a Dean–Stark
apparatus over 30 min. After removing the volatiles in vacuo, the
residue was purified by silica gel column chromatography using
CHCl3 as the eluent. The crude product was further purified by
size exclusion chromatography using THF as the eluent to obtain
5 as a deep blue solid (23 mg, 44%). 1H NMR: d 7.44–7.48 (m, 3
H, ArH and C CH), 7.15–7.19 (m, 3 H, ArH and C CH), 7.00
(d, J = 8.8 Hz, 2 H, ArH), 6.70 (d, J = 8.8 Hz, 2 H, ArH), 6.57 (s, 1
H, pyrrole-H), 5.95 (s, 1 H, pyrrole-H), 4.17–4.23 (m, 6 H, CH2),
4.08 (s, 4 H, CH2), 3.90 (t, J = 4.4 Hz, 2 H, CH2), 3.76–3.78 (m,
2 H, CH2), 3.66–3.73 (m, 12 H, CH2), 3.55–3.58 (m, 2 H, CH2),
3.38 (s, 3 H, CH3), 2.57 (s, 3 H, CH3), 1.46 (s, 3 H, CH3), 1.41
1
CH3), 1.42 (s, 3 H, CH3); 13C{ H} NMR: d 170.1, 159.3, 153.7,
153.4, 148.6, 142.9, 141.6, 139.4, 136.4, 133.3, 131.8, 129.4, 129.1,
127.3, 125.4, 120.7, 117.4, 115.1, 112.3, 71.9, 70.8, 70.6, 70.5, 70.4,
69.7, 69.4, 67.4, 61.5, 59.0, 50.7, 41.5, 29.6, 14.8, 14.5; MS (ESI):
an isotopic cluster peaking at m/z 880 {100%, [M + H]+}; HRMS
(ESI): m/z calcd for C45H61BF2N5O10 [M + H]+: 880.4482, found:
880.4495.
Synthesis of monostyryl BODIPY 8
According to the above procedure, 6 (20 mg, 23 mmol) was treated
with 2-aminoethanol (71 mL, 1.18 mmol) in CH3CN (5 mL) to
1
give 8 as a deep blue solid (15 mg, 70%). H NMR: d 7.44–7.48
1
(s, 3 H, CH3), 1.27 (t, J = 7.2 Hz, 6 H, CH3); 13C{ H} NMR: d
(m, 3 H, ArH and C CH), 7.24 (t, J = 5.2 Hz, 2 H, NH), 7.13–
7.17 (m, 3 H, ArH and C CH), 7.00 (d, J = 8.4 Hz, 2 H, ArH),
6.62 (d, J = 8.8 Hz, 2 H, ArH), 6.57 (s, 1 H, pyrrole-H), 5.97
(s, 1 H, pyrrole-H), 4.18 (t, J = 4.4 Hz, 2 H, CH2), 3.90 (t, J =
4.4 Hz, 2 H, CH2), 3.76–3.78 (m, 2 H, CH2), 3.69–3.72 (m, 6 H,
CH2), 3.66–3.68 (m, 2 H, CH2), 3.56–3.60 (m, 6 H, CH2), 3.41–
3.45 (m, 4 H, CH2), 3.39 (s, 3 H, CH3), 3.27 (s, 4 H, CH2), 2.77
(t, J = 7.2 Hz, 4 H, CH2), 2.56 (s, 3 H, CH3), 1.45 (s, 3 H, CH3),
170.2, 159.2, 154.4, 152.9, 148.4, 142.8, 140.9, 139.0, 137.2, 133.3,
131.6, 129.5, 129.3, 127.5, 124.8, 120.3, 117.5, 115.0, 114.6, 111.8,
71.9, 70.8, 70.6, 70.5, 69.7, 68.9, 68.6, 67.4, 60.8, 59.0, 51.0, 14.8,
14.5, 14.4, 14.1; MS (ESI): an isotopic cluster peaking at m/z 851
{100%, [M + H]+}; HRMS (ESI): m/z calcd for C45H59BF2N3O10
[M + H]+: 850.4256, found: 850.4234.
1
1.42 (s, 3 H, CH3); 13C{ H} NMR: d 170.2, 159.3, 154.0, 153.4,
Synthesis of monostyryl BODIPY 6
147.3, 142.9, 141.5, 139.4, 136.7, 133.4, 131.8, 129.5, 127.4, 125.6,
120.6, 117.6, 115.1, 112.0, 71.9, 70.9, 70.7, 70.6, 69.7, 67.5, 61.5,
59.1, 50.8, 42.4, 36.0, 29.7, 14.9, 14.6, 14.5; MS (ESI): an isotopic
cluster peaking at m/z 911 {100%, [M]+}; HRMS (ESI): m/z calcd
for C45H60BF2N5O8S2 [M]+: 911.3947, found: 911.3957. The purity
of this compound was also checked by reversed-phase analytical
HPLC on a Apollo-C18 column (5 mm, 4.6 mm ¥ 250 mm) using
a Shimadzu CBM-20A controller with a SPD-M20A diode array
detector. The absorbance at 600 nm was monitored. The mobile
phases A and B were H2O and CH3CN respectively. The elution
programme was set as follows: from 0 to 18 min, the percentage
of eluent B increased from 10% to 100%; from 18 to 25 min, the
percentage of eluent B maintained at 100%; from 25 to 27 min, the
percentage of eluent B decreased from 100% to 10%; from 27 to
30 min, the percentage of eluent B maintained at 10%. The flow
rate was fixed at 0.8 mL min-1. As shown in Fig. S13 (ESI†), only a
single sharp peak was observed with a retention time of 17.8 min.
According to the above procedure, BODIPY 1 (30 mg, 62 mmol)
was treated with benzaldehyde 4 (100 mg, 0.26 mmol), glacial
acetic acid (52 mL) and piperidine (43 mL) in toluene (10 mL) to
1
give 6 as a dark blue solid (21 mg, 40%). H NMR: d 7.46–7.51
(m, 3 H, ArH and C CH), 7.15–7.19 (m, 3 H, ArH and C CH),
7.01 (d, J = 8.8 Hz, 2 H, ArH), 6.68 (d, J = 8.8 Hz, 2 H, ArH),
6.58 (s, 1 H, pyrrole-H), 5.96 (s, 1 H, pyrrole-H), 4.18 (t, J = 4.4
Hz, 2 H, CH2), 3.91 (t, J = 4.4 Hz, 2 H, CH2), 3.70–3.80 (m, 10
H, CH2 and CH3), 3.66–3.68 (m, 2 H, CH2), 3.62 (t, J = 7.6 Hz,
4 H, CH2), 3.56–3.58 (m, 2 H, CH2), 3.39 (s, 3 H, CH3), 3.29 (s,
4 H, CH2), 2.86 (t, J = 7.6 Hz, 4 H, CH2), 2.57 (s, 3 H, CH3),
1
1.46 (s, 3 H, CH3), 1.42 (s, 3 H, CH3); 13C{ H} NMR: d 170.7,
159.3, 154.1, 153.2, 147.3, 142.8, 141.2, 139.2, 136.8, 133.8, 133.4,
131.7, 129.5, 127.5, 125.5, 120.5, 117.5, 115.0, 111.8, 111.0, 71.9,
70.9, 70.6, 70.5, 69.7, 67.5, 59.0, 52.5, 50.8, 33.4, 29.7, 14.9, 14.6;
MS (ESI): an isotopic cluster peaking at m/z 854 {100%, [M +
H]+}; HRMS (ESI): m/z calcd for C43H55BF2N3O8S2 [M + H]+:
854.3486, found: 854.3472.
Acknowledgements
Synthesis of monostyryl BODIPY 7
This work was supported by a strategic investments scheme
administered by The Chinese University of Hong Kong.
2-Aminoethanol (71 mL, 1.18 mmol) was added to a solution of 5
(20 mg, 24 mmol) in CH3CN (5 mL). The mixture was heated under
reflux for 3 h. After removing the volatiles in vacuo, the residue was
mixed with water (10 mL), then extracted with CH2Cl2 (10 mL ¥
3). The combined organic layer was dried over anhydrous Na2SO4
and concentrated under reduced pressure. The crude product was
chromatographed on a silica gel column using CHCl3 as the eluent.
Compound 7 was obtained as a deep blue solid (15 mg, 70%). 1H
NMR: d 7.44–7.49 (m, 3 H, ArH and C CH), 7.14–7.17 (m, 3
References
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