PAPER
3-Substituted Phthalic Acid Derivatives by Sonogashira Coupling Reaction
763
3-(Oct-1-ynyl)-N-phenylphthalimide (3a)
purified by crystallization (MeOH, 5 mL). The product was ob-
tained as colorless crystals; yield: 230 mg (71%); mp 185 °C;
Rf = 0.57 (cyclohexane–EtOAc, 3:1).
1H NMR (400 MHz, CDCl3): d = 7.37–7.54 (m, 8 H, Ph), 7.66–7.68
(m, 2 H, PhH), 7.72–7.76 (m, 1 H, Phth), 7.84–7.90 (m, 2 H, Phth).
13C NMR (100 MHz, CDCl3): d = 84.6 (C≡C), 97.3 (C≡C), 120.8
(Phth), 122.2 (Ph), 122.9 (Phth), 126.6 (Ph), 128.1 (Ph), 128.4 (Ph),
129.1 (Ph), 129.3 (Ph), 130.6 (Phth), 131.6 (Phth), 132.1 (Ph), 132.4
(Ph), 133.8 (Phth), 137.8 (Phth), 165.9 (CO), 166.4 (CO).
MS (EI): m/z (%) = 323 (100) [M]+, 295 (50), [M – CO]+.
HRMS (EI): m/z [M]+ calcd for C22H13NO2: 323.0946; found:
Phthalimide 3a was prepared according to the general procedure us-
ing oct-1-yne (0.22 mL, 1.5 mmol). The crude product was purified
by crystallization (MeOH, 5 mL). The product was obtained as col-
orless crystals; yield: 302 mg (91%); mp 225 °C; Rf = 0.50 (cyclo-
hexane–EtOAc, 3:1).
1H NMR (300 MHz, CDCl3): d = 0.90 (t, J = 7.0 Hz, 3 H, CH3),
1.30–1.34 (m, 4 H, alkyl), 1.45–1.52 (m, 2 H, alkyl), 1.64–1.71 (m,
2 H, C≡CCH2CH2), 3.14 (t, J = 7.2 Hz, 2 H, C≡CCH2), 7.38–7.52
(m, 5 H, Ph), 7.66–7.74 (m, 2 H, Phth), 7.83–7.85 (m, 1 H, Phth).
13C NMR (75 MHz, CDCl3): d = 13.7 (CH3), 18.8 (CH2), 21.8
(CH2), 27.6 (CH2), 27.7 (CH2), 30.6 (CH2), 76.2 (C≡C), 98.5 (C≡C),
119.9 (Phth), 122.3 (Phth), 127.3 (Ph), 127.9 (Ph), 128.6 (Ph), 130.3
(Phth), 131.7 (Phth), 132.2 (Ph), 134.2 (Phth), 137.9 (Phth), 165.4
(CO), 165.0 (CO).
323.0945.
N-Phenyl-3-[(triisopropylsilyl)ethynyl]phthalimide (3e)
Phthalimide 3e was prepared according to the general procedure us-
ing ethynyltriisopropylsilane (1.12 mL, 5.0 mmol). The crude prod-
uct was purified by column chromatography (cyclohexane–EtOAc,
9:1). The product was obtained as off-white crystals; yield: 332 mg
(82%); mp 98 °C; Rf = 0.77 (cyclohexane–EtOAc, 3:1).
MS (EI): m/z (%) = 331 (16) [M]+, 302 (4) [M – C2H5]+, 274 (20)
[M – C4H9]+, 261 (100) [M – C5H10]+.
HRMS (EI): m/z [M]+ calcd for C22H21NO2: 331.1572; found:
331.1572.
1H NMR (300 MHz, CDCl3): d = 1.17–1.18 (m, 21 H, i-Pr), 7.37–
7.53 (m, 5 H, Ph), 7.67–7.72 (m, 1 H, Phth), 7.81–7.90 (m, 2 H,
Phth).
13C NMR (75 MHz, CDCl3): d = 11.3 [CH(CH3)2], 18.6 (CH3),
100.8 (C≡C), 101.1 (C≡C), 120.7 (Phth), 123.0 (Phth), 126.7 (Ph),
128.1 (Ph), 129.1 (Ph), 131.0 (Phth), 131.6 (Phth), 132.4 (Ph), 133.6
(Phth), 139.1 (Phth), 165.3 (CO), 166.5 (CO).
3-(Hex-1-ynyl)-N-phenylphthalimide (3b)
Phthalimide 3b was prepared according to the general procedure us-
ing hex-1-yne (0.17 mL, 1.5 mmol). The crude product was purified
by crystallization (MeOH, 5 mL). The product was obtained as off-
white crystals; yield: 279 mg (92%); mp 105 °C; Rf = 0.63 (cyclo-
hexane–EtOAc, 3:1).
1H NMR (400 MHz, CDCl3): d = 0.95 (t, J = 7.4 Hz, 3 H, CH3),
1.47–1.56 (m, 2 H, alkyl), 1.63–1.70 (m, 2 H, alkyl), 2.53 (t, J = 7.2
Hz, 2 H, C≡CCH2), 7.37–7.52 (m, 5 H, Ph), 7.65–7.73 (m, 2 H,
Phth), 7.82–7.84 (m, 1 H, Phth).
MS (EI): m/z (%) = 403 (8) [M]+, 388 (8) [M – CH3]+, 360 (100) [M
– C3H7]+.
HRMS (EI): m/z [M – C3H7]+ calcd for C22H22NO2Si: 360.1420;
13C NMR (100 MHz, CDCl3): d = 13.6 (CH3), 19.5 (CH2), 22.0
(CH2), 30.4 (CH2), 76.0 (C≡C), 99.7 (C≡C), 121.7 (Phth), 122.4
(Phth), 126.6 (Ph), 128.0 (Ph), 129.0 (Ph), 130.5 (Phth), 131.6
(Phth), 132.3 (Ph), 133.7 (Phth), 138.4 (Phth), 166.0 (CO), 166.5
(CO).
found: 360.1424.
Anal. Calcd for C25H29NO2Si: C, 74.40; H, 7.24; N, 3.47. Found: C,
74.09; H, 7.16; N, 3.46.
N-Phenyl-3-(3-pyridylethynyl)phthalimide (3f)
MS (EI): m/z (%) = 303 (12) [M]+, 288 (4) [M – CH3]+, 274 (16) [M
Phthalimide 3f was prepared according to the general procedure us-
ing 3-ethynylpyridine (0.51 mL, 5.0 mmol). The crude product was
purified by column chromatography (cyclohexane–EtOAc, 3:1).
The product was obtained as yellowish crystals; yield: 178 mg
(55%); mp 187 °C; Rf = 0.26 (cyclohexane–EtOAc, 3:1).
– C2H5]+, 261 (100) [M – C3H6]+.
HRMS (EI): m/z [M]+ calcd for C20H17NO2: 303.1259; found:
303.1268.
Anal. Calcd for C20H17NO2: C, 79.18; H, 5.65; N, 4.62. Found: C,
78.78; H, 5.72; N, 4.59.
1H NMR (300 MHz, CDCl3): d = 7.19–7.25 (m, 1 H, Py), 7.31–7.47
(m, 5 H, Ph), 7.67–7.72 (m, 1 H, Phth), 7.78–7.81 (m, 1 H, Phth),
7.84–7.87 (m, 1 H, Phth), 7.85–7.89 (m, 1 H, Py), 8.51–8.53 (m, 1
H, Py), 8.78–8.79 (m, 1 H, Py).
13C NMR (75 MHz, CDCl3): d = 87.5 (C≡C), 93.5 (C≡C), 119.5
(Py), 119.9 (Phth), 123.1 (Py), 123.5 (Phth), 126.6 (Ph), 128.2 (Ph),
129.1 (Ph), 130.9 (Phth), 131.4 (Phth), 132.5 (Ph), 134.0 (Phth),
137.8 (Phth), 139.1 (Py), 149.5 (Py), 152.5 (Py), 165.8 (CO), 166.6
(CO).
3-(3,3-Dimethylbut-1-ynyl)-N-phenylphthalimide (3c)
Phthalimide 3c was prepared according to the general procedure us-
ing 3,3-dimethylbutyne (0.62 mL, 5.0 mmol). The crude product
was purified by column chromatography (cyclohexane–EtOAc,
9:1). The product was obtained as colorless crystals; yield: 267 mg
(88%); mp 180 °C; Rf = 0.75 (cyclohexane–EtOAc, 3:1).
1H NMR (400 MHz, CDCl3): d = 1.39 (s, 9 H, t-Bu), 7.37–7.52 (m,
5 H, Ph), 7.65–7.73 (m, 2 H, Phth), 7.82–7.84 (m, 1 H, Phth).
13C NMR (100 MHz, CDCl3): d = 28.4 [C(CH3)3], 30.6 (CH3), 76.0
(C≡C), 107.3 (C≡C), 121.8 (Phth), 122.3 (Phth), 126.8 (Ph), 128.1
(Ph), 129.1 (Ph), 130.6 (Phth), 131.6 (Phth), 132.3 (Ph), 133.6
(Phth), 138.2 (Phth), 166.0 (CO), 166.6 (CO).
MS (EI): m/z (%) = 324 (100) [M]+, 296 (28) [M – CO]+.
HRMS (EI): m/z [M]+ calcd for C21H12N2O2: 324.0899; found:
324.0895.
N-Phenyl-3-(2-pyridylethynyl)phthalimide (3g)
Phthalimide 3g was prepared according to the general procedure us-
ing 2-ethynylpyridine (0.51 mL, 5.0 mmol). The crude product was
purified by column chromatography (cyclohexane–EtOAc, 3:2).
The product was obtained as yellowish crystals; yield: 58 mg
(18%); mp 144 °C; Rf = 0.21 (cyclohexane–EtOAc, 3:1).
MS (EI): m/z (%) = 303 (88) [M]+, 288 (100) [M – CH3]+, 211 (16)
[M – CH3 – Ph]+, 169 (44) [M – C4H9 – Ph]+.
HRMS (EI): m/z [M]+ calcd for C20H17NO2: 303.1259; found:
303.1260.
1H NMR (400 MHz, CDCl3): d = 7.18–7.24 (m, 2 H, Ph), 7.38–7.39
(m, 1 H, Py), 7.43–7.52 (m, 3 H, Ph), 7.65–7.70 (m, 2 H, Py), 7.72–
7.76 (m, 1 H, Phth), 7.90–7.92 (m, 1 H, Phth), 8.59 (m, 1 H, Phth),
8.62 (m, 1 H, Py).
N-Phenyl-3-(phenylethynyl)phthalimide (3d)
Phthalimide 3d was prepared according to the general procedure us-
ing phenylacetylene (0.16 mL, 1.5 mmol). The crude product was
Synthesis 2007, No. 5, 761–765 © Thieme Stuttgart · New York