H. Maeda et al. / Journal of Photochemistry and Photobiology A: Chemistry 349 (2017) 7–17
15
naphthalenedicarbonyl dichloride) was dried under reduced
pressure. To a stirred THF (30 mL) solution of 8-phenyl-(‘)-menthol
(1.576 g, 6.8 mmol) and pyridine (4 mL) was slowly added a THF
(20 mL) solution of the residue (2,3-naphthalenedicarbonyl
dichloride) under a N2 atmosphere. The resulting solution was
stirred at reflux overnight. The mixture was extracted with Et2O.
The organic layer was dried over Na2SO4, filtered, and concentrated
in vacuo. The residue was subjected to silica gel column
chromatography (CHCl3, Rf = 0.93) followed by HPLC (GPC) to give
bis(8-phenyl-(‘)-menthyl) 2,3-naphthalenedicarboxylate (1f,
1.188 g, 1.9 mmol, 53% yield). Colorless solid; mp 79–82 ꢀC; 1H
(125 MHz, CDCl3) d 22.2, 73.9, 126.4, 128.0, 128.5, 128.6, 128.8,
129.2, 130.2, 133.5, 141.6, 166.9 ppm; MS (FAB) m/z (relative
intensity, %) 199 (28), 217 (48), 321 (6), 425 (M++1, 13).
4.11. Preparation of bis((R)-1-phenylethyl) 2,3-
naphthalenedicarboxylate (1j)
A
mixture of 2,3-naphthalenedicarboxylic acid (0.432 g,
2.0 mmol), (R)-1-phenylethanol (0.611 g, 5.0 mmol), 4-dimethyla-
minopyridine (0.484 g, 4.0 mmol), and CH2Cl2 (15 mL) was stirred
for 5 min at room temperature under a N2 atmosphere. To the
solution was added CH2Cl2 (15 mL) solution of dicyclohexylcarbo-
diimide (1.268 g, 6.1 mmol). The resulting solution was stirred
overnight. The precipitate was removed by filtration. HCl aq.
(0.5 M) and Et2O were added to the filtrate. The organic layer was
washed with sat. NaHCO3 aq., separated, dried over Na2SO4,
filtered, and concentrated in vacuo. The residue was subjected to
silica gel column chromatography (CHCl3, Rf = 0.4) followed by
HPLC (GPC) to give bis((R)-1-phenylethyl) 2,3-naphthalenedicar-
boxylate (1j, 0.589 g,1.4 mmol, 70% yield). Colorless liquid; 1H NMR
NMR (500 MHz, CDCl3)
d 0.89 (qd, J = 12.4, 2.8 Hz, 4H), 0.94 (d,
J = 6.4 Hz, 6H), 1.08–1.22 (m, 4H), 1.31 (s, 6H), 1.38 (s, 6H), 1.52–1.59
(m, 2H), 1.63–1.66 (m, 2H), 2.09–2.14 (m, 2H), 2.24–2.26 (m, 2H),
5.14 (td, J = 10.8, 4.3 Hz, 2H), 6.86 (t, J = 7.3 Hz, 2H), 7.09 (t, J = 7.8 Hz,
4H), 7.27 (d, J = 5.5 Hz, 2H), 7.28 (d, J = 7.3 Hz, 2H), 7.59 (dd, J = 6.0,
3.2 Hz, 2H), 7.69 (s, 2H), 7.82 (dd, J = 6.2, 3.4 Hz, 2H) ppm; 13C NMR
(125 MHz, CDCl3)
d 22.1, 26.4, 27.2, 27.3, 31.5, 34.9, 40.2, 41.5, 50.9,
76.0, 125.0, 125.6, 128.0, 128.1, 128.8, 129.4, 129.7, 133.2, 151.5,
166.6 ppm; MS (FAB) m/z (relative intensity, %) 199 (35), 217 (93),
431 (11), 645 (M++1, 13).
(500 MHz, CDCl3)
d 1.59 (d, J = 6.9 Hz, 6H), 6.06 (q, J = 6.7 Hz, 2H),
7.27–7.30 (m, 2H), 7.32–7.43 (m, 8H), 7.61 (dd, J = 6.4, 3.2 Hz, 2H),
4.9. Preparation of di-(d)-menthyl 2,3-naphthalenedicarboxylate (1h)
7.91 (dd, J = 6.2, 3.4 Hz, 2H), 8.23 (s, 2H) ppm; 13C NMR (125 MHz,
CDCl3)
d 22.2, 74.0, 126.3, 126.4, 128.0, 128.6, 128.8, 129.2, 130.1,
A
mixture of 2,3-naphthalenedicarboxylic acid (0.981 g,
133.5,141.7,166.9 ppm; MS(FAB) m/z (relative intensity, %) 199 (16),
4.5 mmol), SOCl2 (4 mL, 55.1 mmol), and DMF (few drops) was
stirred at reflux overnight under a N2 atmosphere. Excess SOCl2
was removed by distillation. The residue (2,3-naphthalenedicar-
bonyl dichloride) was dried under reduced pressure. To a stirred
THF (20 mL) solution of (d)-menthol (1.952 g, 12.5 mmol) and
pyridine (4 mL) was slowly added a THF (20 mL) solution of the
residue (2,3-naphthalenedicarbonyl dichloride) under a N2 atmo-
sphere. The resulting solution was stirred at reflux overnight. The
mixture was extracted with Et2O. The organic layer was dried over
Na2SO4, filtered, and concentrated in vacuo. The residue was
subjected to silica gel column chromatography (toluene, Rf = 0.38)
followed by HPLC (GPC) to give di-(d)-menthyl 2,3-naphthalene-
dicarboxylate (1h, 0.403 g, 0.82 mmol, 18% yield). Colorless liquid;
217 (43), 321 (7), 425 (M++1, 9).
4.12. Preparation of 3-methylfuran (2c) [71,72]
To
a stirred Et2O (500 mL) solution of 4,4-dimethoxy-2-
butanone (80 mL, 0.60 mol) and methyl chloroacetate (90 mL,
1.03 mol) was added MeONa (54 g, 1.00 mol) at À5 ꢀC under a N2
atmosphere, and the resulting solution was stirred at À5 ꢀC for 2 h,
and at room temperature overnight. To the solution was slowly
added a mixture of glacial acetic acid (7 mL) and H2O (93 mL) at
0 ꢀC. The organic layer was decantated. Aqueous phase was washed
with Et2O. The combined organic layers were washed with sat.
NaHCO3 aq. and brine, separated, dried over Na2SO4, filtered, and
concentrated in vacuo. The residue was distilled (bp 72–78 ꢀC/
8 mmHg) to give 2-methoxycarbonyl-3-methylfuran (71 g,
0.51 mol, 85% yield).
1H NMR (500 MHz, CDCl3)
d 0.86 (d, J = 6.9 Hz, 6H), 0.92 (d,
J = 7.3 Hz, 6H), 0.96 (d, J = 6.9 Hz, 6H), 1.11–1.19 (m, 4H), 1.49–1.61
(m, 6H), 1.72–1.75 (m, 4H), 2.02 (quint-d, J = 6.9, 2.6 Hz, 2H), 2.25–
2.27 (m, 2H), 5.00 (td, J = 11.0, 4.6 Hz, 2H), 7.61 (dd, J = 6.4, 3.2 Hz, 2
H), 7.93 (dd, J = 6.0, 3.2 Hz, 2H), 8.19 (s, 2H) ppm; 13C NMR
A
mixture of 2-methoxycarbonyl-3-methylfuran (26 g,
0.19 mol) and 20% NaOH aq. (60 mL) was stirred at reflux for 2 h.
After the solution was cooled to 0 ꢀC, conc HCl (35 mL) was slowly
added to give colorless crystals of 3-methylfuran-2-carboxylic acid
(3.199 g, 15% yield).
(125 MHz, CDCl3)
d 16.6, 21.1, 22.3, 23.6, 26.3, 31.6, 34.5, 40.8, 47.3,
75.6, 128.4, 128.7, 129.7, 129.9, 133.5, 167.2 ppm; MS (FAB) m/z
(relative intensity, %) 199 (80), 217 (100), 355 (18), 493 (M++1, 25).
A
mixture of 3-methylfuran-2-carboxylic acid (3.20 g,
4.10. Preparation of bis((S)-1-phenylethyl) 2,3-
naphthalenedicarboxylate (1i)
29 mmol), Cu (0.90 g, 14.2 mmol), and quinoline (10 mL,
84.4 mmol) was heated to 260 ꢀC, and a fraction (bp 65.5 ꢀC) is
collected and assigned to 3-methylfuran (colorless liquid, 65–70%
yield) [73].
A
mixture of 2,3-naphthalenedicarboxylic acid (1.081 g,
4.9 mmol), (S)-1-phenylethanol (1.567 g, 12.8 mmol), 4-dimethy-
laminopyridine (1.118 g, 9.2 mmol), and CH2Cl2 (30 mL) was stirred
for 5 min at room temperature under a N2 atmosphere. To the
solution was added a CH2Cl2 (30 mL) solution of dicyclohexylcar-
bodiimide (3.061 g, 14.8 mmol), and the solution was stirred
overnight. The precipitate was removed by filtration. HCl aq.
(0.5 M) and Et2O were added to the filtrate. The organic layer was
washed with sat. NaHCO3 aq., separated, dried over Na2SO4,
filtered, and concentrated in vacuo. The residue was subjected to
silica gel column chromatography (AcOEt:hexane = 1:1, Rf = 0.8)
followed by HPLC (GPC) to give bis((S)-1-phenylethyl) 2,3-
naphthalenedicarboxylate (1i, 1.402 g, 3.3 mmol, 67% yield).
4.13. Preparation of 3-(methoxymethyl)furan (2d) [74]
To a mixture of DMF (10 mL) and NaH (1.734 g, 72.3 mmol) was
added DMF (40 mL) solution of 3-furanmethanol (1.4 mL,
16.3 mmol) under a N2 atmosphere, and the suspension was
stirred for 30 min at room temperature. To the mixture was added
MeI (3 mL, 48.2 mmol), and the mixture was stirred for 3 h at room
temperature. Et2O and brine were added. The organic layer was
separated, dried over Na2SO4, filtered, and concentrated in vacuo.
The residue was subjected to silica gel column chromatography
(petroleum ether:Et2O = 3:1) to give 3-(methoxymethyl)furan (2d,
1.808 g, 16.1 mmol, 99% yield).
Colorless liquid; 1H NMR (500 MHz, CDCl3)
d 1.59 (d, J = 6.4 Hz, 6
H), 6.06 (q, J = 6.7 Hz, 2H), 7.28–7.40 (m, 10H), 7.60 (dd, J = 6.4,
3.2 Hz, 2H), 7.90 (dd, J = 6.2, 3.4 Hz, 2H), 8.22 (s, 2H) ppm; 13C NMR