The Journal of Organic Chemistry
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127.9, 126.5, 121.1, 64.6, 49.9 ppm. FTIR (thin film, νmax): 3090, 2965,
2918, 2117, 1721, 1609, 1532, 1347, 1282, 1243, 1119 cm−1. Mp: 54−
56 °C.
67.2, 23.3 ppm. HRMS (ESI, m/z): calcd for C9H9ClNO4S (M + H)+
261.9941; found 261.9923. Mp: 60−62 °C.
2-Mercaptoethyl 3,4-Dinitrobenzoate (8-NO2). This was
prepared by general procedure G from DNBA (506 mg, 2.39 mmol)
in 10 mL of β-mercaptoethanol. Elution over silica (ethyl acetate/
hexanes 20%) afforded the thiol as an orange oil in 6% yield (39 mg).
MW: 272.23 g/mol. 1H NMR (400 MHz, CDCl3): δ 8.56 (d, 1H, J =
1.6 Hz), 8.41 (dd, 1H, J1 = 8.4 Hz, J2 = 1.6 Hz), 7.97 (d, 1H, J = 8.4
Hz), 4.51 (t, 2H, J = 6.7 Hz), 2.91 (dt, 2H, J1 = 8.6 Hz, J2 = 6.7 Hz),
1.53 (t, 1H, J = 8.6). 13C NMR (100 MHz, CDCl3): δ 162.5, 145.5,
142.7, 134.9, 134.8, 126.5, 125.6, 67.8, 23.2 ppm. HRMS (ESI, m/z):
C9H8N2O6S calcd for (M)+ 272.0103; found 272.0105.
2-Azidoethyl 3,4-Dinitrobenzoate (5-NO2). This was prepared
by general procedure D from tosylate 4-NO2 (409 mg, 1 mmol) and
sodium azide (352 mg, 5.4 equiv). The residue was eluted over silica
gel (50% ethyl acetate/hexanes) to give the azide as a crystalline
orange solid in 46% yield (129 mg). MW: 281.18 g/mol. TLC: 50%
ethyl acetate/hexanes, Rf = 0.45. 1H NMR (400 MHz, CDCl3): δ 8.56
(d, 1H, J = 2 Hz), 8.24 (dd, 1H, J1 = 8.4 Hz, J2 = 2 Hz), 7.39 (d, 1H, J
= 8.4 Hz), 4.51 (t, 2H, J = 5.1 Hz), 3.61 (t, 2H, J = 5.1 Hz). 13C NMR
(150 MHz, CDCl3): δ 163.8, 149.1, 139.5, 134.8, 127.9, 126.6, 121.1,
64.6, 50.0 ppm. FTIR (thin film, νmax): 3101, 2956, 2111, 1719, 1610,
1539, 1352, 1297, 1230, 1117, 1114 cm−1. Mp: 54−57 °C.
2-Iodoethyl 4-Chloro-3-nitrobenzoate (6-Cl). This was pre-
pared by general procedure C from tosylate 4-Cl (354 mg, 0.89 mmol)
and sodium iodide (320 mg, 2.4 equiv) in acetone (5 mL). Elution
over silica gel (20% ethyl acetate/hexanes) afforded the iodide as a
yellow powder in 62% yield (196 mg). MW: 355.51 g/mol. TLC: 50%
ethyl acetate/hexanes, Rf = 0.53. 1H NMR (400 MHz, CDCl3): δ 8.51
(d, 1H, J = 2 Hz), 8.17 (dd, 1H, J1 = 8.4 Hz, J2 = 2 Hz), 7.65 (d, 1H, J
= 8.4 Hz), 4.60 (t, 2H, J = 6.8 Hz), 3.42 (t, 2H, J = 6.8 Hz). 13C NMR
(100 MHz, CDCl3): δ 163.2, 148.1, 133.9, 132.5, 132.2, 129.7, 126.9,
65.9, 0.04 ppm. HRMS (ESI, m/z): calcd for C9H8ClINO4 (M + H)+
355.9187; found 355.9182. Mp: 91−93 °C.
2-(Prop-2-yn-1-yloxy)ethanol (9). Ether 9 was prepared from
ethylene glycol and propargyl bromide in one step by a previously
published method34 (146 mg, 35% yield). The identity of 9 was
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confirmed by H and 13C NMR. Purity of 9 was determined by H
NMR and TLC. Physical and spectroscopic data were found to match
literature data.34
2-(2-(2-(Prop-2-yn-1-yloxy)ethoxy)ethoxy)ethanol (10). Ether
10 was prepared from triethylene glycol and propargyl bromide in one
step by a previously published method45 (133 mg, 17% overall yield).
The identity of 10 was confirmed by 1H and 13C NMR. The purity of
10 was determined by 1H NMR and TLC. Physical and spectroscopic
data were found to match literature data.45
Prop-2-yn-1-yl 4-Chloro-3-nitrobenzoate (11-Cl). This was
prepared by general procedure H from CNBA (1 g, 4.96 mmol) in 10
mL of propargyl alcohol. The ester was obtained as an off-white
powder in 96% yield (1.14 g) by elution over silica gel (20% ethyl
acetate/hexanes) and recrystallization from boiling ethyl acetate. MW:
2-Iodoethyl 3,4-Dinitrobenzoate (6-NO2). Prepared by general
procedure C from tosylate 4-NO2 (409 mg, 1 mmol) and sodium
iodide (398 mg, 2.7 equiv) in acetone (5 mL). Elution over silica gel
(50% ethyl acetate/hexanes) afforded the iodide as an orange oil that
solidified upon standing in 95% yield (348 mg). MW: 366.07 g/mol.
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239.61 g/mol. TLC: 20% ethyl acetate/hexanes, Rf = 0.33. H NMR
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TLC: 50% ethyl acetate/hexanes, Rf = 0.54. H NMR (400 MHz,
(400 MHz, CDCl3): δ 8.55 (d, 1H, J = 2.2 Hz), 8.18 (dd, 1H, J1 = 8.4
Hz, J2 = 2.2 Hz), 7.65 (d, 1H, J = 8.4 Hz), 4.95 (d, 2H, J = 2.8), 2.55
(t, 1H, J = 2.8 Hz). 13C NMR (100 MHz, CDCl3): δ 163.2, 148.1,
133.9, 132.5, 132.3, 129.5, 126.9, 76.1, 53.6 ppm. HRMS (ESI, m/z):
calcd for C10H7ClNO4 (M + H − acetylene radical)+ 216.0064; found
216.0056. Mp: 68−70 °C.
Prop-2-yn-1-yl 3,4-Dinitrobenzoate (11-NO2). This was
prepared by general procedure H from DNBA (250 mg, 1.18
mmol) in 5 mL of propargyl alcohol. Elution of the residue over silica
gel (20% ethyl acetate/hexanes) afforded the ester as a crystalline
yellow solid in 41% yield (121 mg). MW: 250.16 g/mol. TLC: 50%
ethyl acetate/hexanes, Rf = 0.53. 1H NMR (400 MHz, CDCl3): δ 8.60
(d, 1H, J = 1.6 Hz), 8.43 (dd, 1H, J1 = 8.4 Hz, J2 = 2 Hz), 7.97 (d, 1H,
J = 8.4 Hz), 4.99 (d, 2H, J = 2.4 Hz), 2.58 (t, 1H, J = 2.4 Hz). 13C
NMR (100 MHz, CDCl3): δ 162.1, 145.5, 142.7, 135.0, 134.4, 126.7,
125.6, 76.5, 54.2 ppm. HRMS (ESI, m/z): calcd for C10H6N2O6 (M+)
250.0226; found 250.0212. Mp: 79−80 °C.
CDCl3): δ 8.55 (d, 1H, J = 2 Hz), 8.42 (dd, 1H, J1 = 8.4 Hz, J2 = 2
Hz), 7.97 (d, 1H, J = 8.4 Hz), 4.62 (t, 2H, J = 6.6 Hz), 3.43 (t, 2H, J =
6.6 Hz). 13C NMR (150 MHz, CDCl3): δ 162.0, 145.2, 142.4, 134.9,
134.6, 126.4, 125.5, 66.3, −0.17 ppm. HRMS (ESI, m/z): calcd for
C9H8IN2O6 (M + H)+ 366.9427; found 366.9428. Mp: 40−43 °C.
2-(2-(2-Hydroxyethoxy)ethoxy)ethyl 4-Chloro-3-nitroben-
zoate (7-Cl). This was prepared by general procedure A from
CNBA (1 g, 4.96 mmol) and triethylene glycol (2.0 mL, 3 equiv) in 10
mL of DMF/CH2Cl2. The ester was isolated by column chromatog-
raphy (90% ethyl acetate/hexanes) as a light yellow oil in 24% yield
(397 mg). MW: 333.72 g/mol. TLC: 80% ethyl acetate/hexanes, Rf =
0.13. 1H NMR (400 MHz, CDCl3): δ 8.53 (d, 1H, J = 2 Hz), 8.18 (dd,
J1 = 8.4 Hz, J2 = 2 Hz), 7.63 (d, 1H, J = 8.4 Hz), 4.51 (t, 2H, J = 4.8
Hz), 3.83 (t, 2H, J = 4.8 Hz), 3.68 (cm, 8H), 3.59 (t, 2H, J = 4.4 Hz),
2.31 (bs, 1H). 13C NMR (100 MHz, CDCl3): δ 163.3, 147.4, 133.5,
131.9, 131.0, 129.6, 126.2, 72.2, 70.3, 69.9, 68.6, 64.7, 61.2 ppm.
HRMS (ESI, m/z): calcd for C13H16ClNO7Na (M + Na)+ 356.0513;
found 356.0523.
2-(Prop-2-yn-1-yloxy)ethyl 4-Chloro-3-nitrobenzoate (12-
Cl). This was prepared by general procedure I from 2-(prop-2-yn-1-
yloxy)ethanol (ether 9, 229 mg, 2.3 mmol) and CNBA (614 mg, 1.3
equiv). The residue was purified by column chromatography (20%
ethyl acetate/hexanes) to afford the ester as a yellow oil in 35% yield
(228 mg). MW: 283.66 g/mol. TLC: 50% ethyl acetate/hexanes, Rf =
0.45. 1H NMR (400 MHz, CDCl3): δ 8.48 (d, 1H, J = 2 Hz), 8.14 (dd,
1H, J1 = 8.4 Hz, J2 = 2 Hz), 7.61 (d, 1H, J = 8.4 Hz), 4.50 (t, 2H, J =
4.6 Hz), 4.19 (d, 2H, J = 2.4 Hz), 3.85 (t, 2H, J = 4.6 Hz), 2.44 (t, 1H,
J = 2.4). 13C NMR (100 MHz, CDCl3): δ 163.8, 148.0, 133.9, 132.3,
131.8, 130.1, 126.8, 79.3, 75.3, 67.4, 65.0, 58.5 ppm. HRMS (ESI, m/
z): calcd for C12H11ClNO5 (M + H)+ 284.0326; found 284.0326.
2-(Prop-2-yn-1-yloxy)ethyl 3,4-Dinitrobenzoate (12-NO2).
This was prepared by general procedure I from 2-(prop-2-yn-1-
yloxy)ethanol (ether 9, 184 mg, 1.84 mmol) and DNBA (503 mg, 1.3
equiv). The residue was eluted over silica gel (ethyl acetate/hexanes
20%) to give the ester as an orange-brown oil in 79% yield (428 mg).
2-(2-(2-Hydroxyethoxy)ethoxy)ethyl 3,4-Dinitrobenzoate
(7-NO2). This was prepared by general procedure A from DNBA (1
g, 4.71 mmol) and triethylene glycol (1.9 mL, 3 equiv) in 10 mL of
DMF/CH2Cl2. The ester was isolated by column chromatography
(90% ethyl acetate/hexanes) as a yellow oil in 53% yield (859 mg).
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MW: 344.27 g/mol. TLC: 80% ethyl acetate/hexanes, Rf = 0.19. H
NMR (400 MHz, CDCl3): δ 8.61 (s, 1H), 8.43 (d, 1H, J = 7.6 Hz),
7.96 (d, 1H, J = 8 Hz), 4.56 (bt, 2H, J = 4.2 Hz), 3.84 (bt, 2H, J = 4.2
Hz), 3.68 (cm, 6H), 3.60 (b, 2H). 13C NMR (100 MHz, CDCl3): δ
162.9, 145.3, 142.7, 135.0, 134.9, 126.6, 125.5, 72.6, 70.8, 70.4, 68.9,
65.6, 61.8 ppm. HRMS (ESI, m/z): calcd for C13H16N2O9Na (M +
Na)+ 367.0753; found 367.0756.
2-Mercaptoethyl 4-Chloro-3-nitrobenzoate (8-Cl). This was
prepared by general procedure G from CNBA (1 g, 4.96 mmol) in 10
mL of β-mercaptoethanol. Elution over silica (ethyl acetate/hexanes
20%) afforded the thiol as an off-white solid in 25% yield (324 mg).
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MW: 294.22 g/mol. TLC: 50% ethyl acetate/hexanes, Rf = 0.33. H
MW: 261.68 g/mol. TLC: 50% ethyl acetate/hexanes, Rf = 0.50. H
NMR (400 MHz, CDCl3): δ 8.58 (d, 1H, J = 1.6 Hz), 8.42 (dd, 1H, J1
= 8.4 Hz, J2 = 1.6 Hz), 7.96 (d, 1H, J = 8.4 Hz), 4.56 (m, 2H), 4.21 (d,
2H, J = 2.4 Hz), 3.88 (m, 2H), 2.46 (t, 1H, J = 2.4 Hz). 13C NMR
(100 MHz, CDCl3): δ 162.7, 145.2, 142.5, 135.0, 134.8, 126.4, 125.5,
NMR (400 MHz, CDCl3): δ 8.46 (d, 1H, J = 2 Hz), 8.14 (dd, 1H, J1 =
8.4 Hz, J2 = 2 Hz), 7.62 (d, 1H, J = 8.4 Hz), 4.45 (t, 2H, J = 6.7 Hz),
2.87 (dt, 2H, J1 = 8.6 Hz, J2 = 6.7 Hz), 1.52 (t, 1H, J = 8.6). 13C NMR
(100 MHz, CDCl3): δ 163.5, 148.0, 133.8, 132.4, 132.0, 129.9, 126.7,
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dx.doi.org/10.1021/jo401278x | J. Org. Chem. 2013, 78, 9647−9658