F
A. A. Provatas, G. A. Epling, and J. D. Stuart
was suction-filtered and washed with distilled water. The solid
collected was recrystallized from methanol to give a pale yellow
solid (0.83 g, 78 %), mp 109–1108C. dH (CDCl3) 8.16 (1H, d),
8.41 (1H, d), 8.13 (2H, d), 7.99 (1H, s), 7.45–7.25 (4H, m), 5.08
(2H, s), 4.00 (3H, s), 2.44 (3H, s).
hydride. Isolation, as performed for 2a, gave a pale yellow solid
(2.4 g, 50 %), mp 222–2248C. dH ([D6]DMSO) 8.42 (1H, s),
8.17–8.00 (3H, m), 7.44 (1H, s), 7.08 (2H, d), 5.72 (1H, t), 5.10
(2H, s), 4.01 (3H, s).
Synthesis of 2-(3,4-Dichlorophenyl)-6-methoxy-4-
quinoline Chloride (3c)
Procedure 4: Synthesis of 2-(p-Tolyl)-6-methoxy-4-
quinoline 2-Naphthol Ether (4a)
The procedure for preparing compound 3a was followed
using 1.0 g (0.0030 mol) 2-(3,4-dichlorophenyl)-6-methoxy-4-
quinoline methanol and 7.0 mL (11.45 g, 0.096 mol) thionyl
chloride. Isolation, as performed for 3a, gave a yellow solid
(0.74 g, 70 %), mp 210–2128C. dH ([D6]DMSO) 8.46 (1H, s),
8.35–8.21 (3H, m), 7.52 (1H, s), 7.12 (2H, d), 5.37 (2H, s), 4.07
(3H, s).
A 100 mL flask was equipped with a magnetic stirring bar. In
the flask were added 1.26 g (0.004 mol) 2-(p-tolyl)-6-methoxy-
4-quinoline chloride (3a) and 50 mL dry DMF. The mixture was
stirred until the quinoline chloride dissolved completely in DMF
(,15 min). Meanwhile, a solution of sodium hydroxide pellets
(0.84 g, 0.021 mol) dissolved in a minimum volume of DMF was
prepared. Then, 2-naphthol (3.05 g, 0.021 mol) was added to the
sodium hydroxide solution. This solution was added slowly with
the use of an addition funnel to the quinoline chloride solution.
The addition took ,30 min. The reaction mixture was allowed
to stir for 3 h. After completion of the reaction, as monitored by
thin layer chromatography, 10 mL distilled water and 10 mL
concentrated hydrochloric acid were added slowly. A pale
yellow precipitation formed. Then, the flask was cooled first
to room temperature and then in an ice bath. The solid was
collected using suction filtration and washed with distilled
water. The solid collected was dissolved in ethyl acetate, and
the mixture was extracted from a saturated solution of sodium
bicarbonate (or sodium hydroxide) three times. The ethyl
acetate layer was evaporated to dryness on a rotary evaporator,
and a pale yellow solid was collected (1.085 g, 67 %), mp 122–
1238C. dH (CDCl3) 8.17 (1H, d), 8.05 (3H, d), 7.85–7.82
(3H, m), 7.45–7.26 (8H, m), 5.65 (2H, s), 3.95 (3H, s), 2.44
(3H, s). m/z (EI, 70 eV) 405 (5.0 ꢂ 104, [M]þ), 263 (5.0 ꢂ 104),
262 (2.5 ꢂ 105), 219 (5.0 ꢂ 104), 115 (5.0 ꢂ 104), 63 (2.5 ꢂ 104).
Synthesis of 2-(3,4-Dichlorophenyl)-6-methoxy-4-
quinoline-2-carboxyl-4-quinolinol Ether (4c)
The procedure for preparing compound 4a was followed
using 0.5 g (0.0014 mol) 2-(3,4-dichlorophenyl)-6-methoxy-4-
quinoline chloride, 0.54 g (0.00285 mol) 2-carboxyl-4-quinolinol,
and 0.11 g (0.0028 mol) sodium hydroxide. Isolation, as per-
formed for 4a, gave a yellow solid (0.51 g, 73 %), mp 139–
1418C. dH ([D6]DMSO) 8.45 (1H, s), 8.29–8.03 (4H, m), 7.96
(1H, s), 7.69 (1H, s), 7.44 (1H, s), 7.12 (2H, d), 6.84 (2H, d), 5.99
(2H, s), 4.06 (3H, s).
General Procedure for Photocleavage of Quinolinyl Methyl
Ether-Protected Alcohols under Visible Light
Into a 100 mL round-bottom Pyrex flask, equipped with a stir-
ring bar magnet and a reflux condenser, were added 0.196 mmol
quinolinyl methyl ether and (0.5–4.0) ꢂ 10ꢁ3 M sensitizer
dye (methylene green, eosin B, dinitro-methylene green). The
reaction mixture was dissolved in a solvent system of choice
(90 mL methanol/10 mL distilled water, 99 mL methanol/1 mL
acetic acid, 95 mL methanol/5 mL acetic acid). Then, D-sorbitol
(0.18 %) was added as a radical scavenger. If pertinent to the trial,
0.01 M triethylamine was then added. The resulting solution was
purged with nitrogen gas for 15 min. The solution was irradiated
with a 150 W spotlight for 5–30 min. The distance between the
centre of the flask and the spotlight was 6 cm. After irradiation
was complete, the reaction mixture was diluted in ethyl acetate
and washed with a solution of saturated sodium chloride three
times. The ethyl acetate layers were combined and evaporated to
dryness on a rotary evaporator. Then, GCMS analysis was per-
formed. The percentageconversion ofthe quinolinyl methyl ether
to the alcohol was calculated based on the integrals. The per-
centage yield of alcohol was determined by the amount of alcohol
in the mixture (alcohol fraction obtained by flash chromatogra-
phy). For more reliable quantification of the alcohol, the reaction
mixture was treated with acetic anhydride and sodium acetate to
convert the alcohol into the alcohol acetate. GCMS was per-
formed using biphenyl as the internal standard.
Synthesis of 2-(p-Tolyl)-6-methoxy-4-quinoline
3-tert-Butylphenol Ether (4b)
The procedure for synthesizing compound 4a was followed
using 0.5 g (0.0016 mol) 2-(p-tolyl)-6-methoxy-4-quinoline
chloride (3a), 1.26 g (0.0084 mol) 3-tert-butylphenol, and
0.33 g (0.0082 mol) sodium hydroxide were used. Isolation, as
performed for 4a, gave a pale yellow solid (0.35 g, 54 %), mp
117–1188C. dH (CDCl3) 8.45 (1H, s), 8.19 (1H, s), 7.64–7.42
(4H, m), 7.41 (1H, s), 6.97–6.66 (5H, m), 5.51 (2H, s), 4.03 (3H,
s), 2.41 (3H, s), 1.30 (9H, s). m/z (EI, 70 eV) 411 (1.0 ꢂ 105,
[M]þ), 341 (0.1 ꢂ 105), 262 (5.0 ꢂ 105), 219 (1.0 ꢂ105), 102
(0.1 ꢂ 105), 91 (0.2 ꢂ 105).
Synthesis of 2-(3,4-Dichlorophenyl)-6-methoxy-4-
quinoline Carboxylic Acid (1c)
The procedure for preparing compound 1a was followed
using 150 g (0.857 mol) 3,4-dichlorobenzaldehyde, 105.4 g
(0.857 mol) of p-anisidine, and 60.7 mL (77.0 g, 0.857 mol)
pyruvic acid. Isolation, as performed for 1a, gave a pale yellow
solid (99.3 g, 33 %), mp 267–2688C. dH ([D6]DMSO) 14.48–
13.94 (1H, br), 8.46 (2H, s), 8.21 (1H, d), 8.09 (2H, d), 7.78
(1H, d), 7.52 (1H, d), 3.92 (3H, s).
Acknowledgements
This project would not have been possible without the invaluable support
and guidance of the late Professor Gary Epling. He was a 1967 graduate of
the Massachusetts Institute of Technology and received his Ph.D degree
from the University of Wisconsin (Zimmerman 1972). His post-doctoral
work was conducted at Yale in 1973. He was a professor at Fordham Uni-
versity from 1973 to 1978, when he came to the Chemistry Department at the
University of Connecticut and served as the Head. Professor Epling has
published over 70 scholarly articles.
Synthesis of 2-(3,4-Dichlorophenyl)-6-methoxy-4-
quinoline Methanol (2c)
The procedure for preparing compound 2a was followed
using 5.0 g (0.0143 mol) 2-(3,4-dichlorophenyl)-6-methoxy-4-
quinoline carboxylicacidand 3.0 g (0.079 mol) lithium aluminium