Synthesis of 6-acyl-5,8-quinolinediols by photo-Friedel-Crafts acylation using sunlight

Article abstract of DOI:10.1016/j.tetlet.2013.04.021

Synthesis of acyl-5,8-quinolinediols using sunlight was investigated. Photo-Friedel-Crafts acylation of quinoline-5,8-dione and aldehyde afforded the corresponding 6-acyl-5,8-quinolinediols regioselectively in moderate to good yields. The compounds have a variety of potential applications.

Full text of DOI:10.1016/j.tetlet.2013.04.021

Tetrahedron Letters 54 (2013) 3147–3149
Contents lists available at SciVerse ScienceDirect
Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
Synthesis of 6-acyl-5,8-quinolinediols by photo-Friedel–Crafts acylation
using sunlight
⇑
Fernando De Leon, Sudhakar Kalagara, Ashley A. Navarro, Shizue Mito
Department of Chemistry, The University of Texas at El Paso, El Paso, TX 79968, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 14 February 2013
Revised 4 April 2013
Accepted 5 April 2013
Available online 13 April 2013
Synthesis of acyl-5,8-quinolinediols using sunlight was investigated. Photo-Friedel–Crafts acylation of
quinoline-5,8-dione and aldehyde afforded the corresponding 6-acyl-5,8-quinolinediols regioselectively
in moderate to good yields. The compounds have a variety of potential applications.
Ó 2013 Elsevier Ltd. All rights reserved.
Keywords:
Solar synthesis
Photochemistry
Friedel–Crafts acylation
Hydroxyquinoline
Quinolinediol
Introduction
were a mixture of quinone and acylated quinolinediols as regioi-
somers with low yield, and the reaction needs to be improved.
Sunlight drives numerous chemical reactions that are essential
for life on earth. It is a unique natural resource that can provide an
endless supply of renewable and clean energy. Consequently, solar
radiation has attracted rising attention in the scientific community.
In synthetic organic photochemistry, artificial UV light has been
used predominantly, but reactions driven by sunlight have been
explored in recent years.
1,4-Quinones have been studied as substrates for many years
due to their great abilities as electron acceptors. Actually, the first
reaction of 1,4-benzoquinone and aldehydes to obtain acylhydro-
quinones was reported in 1891.1 In this Letter the reaction was ex-
posed to sunlight over several months. However, the reaction has
not received much attention for more than a century. Over the last
decade this photo-Friedel–Crafts acylation has drawn renewed
attention from a few research groups.2–5 Mattay and Oelgemöller
began to reinvestigate this reaction using sunlight, and more re-
cently, the Valderrama group reported heteroaromatic acylation.6
As evidenced by recent reports about the solar reaction of 1,4-ben-
zo- and 1,4-naphthoquinones with aldehydes, this synthetic meth-
odology has been in the spotlight.
The products, 6-acyl-5,8-quinolinediols 2, are very interesting: a
number of bioactive compounds bearing quinoline moieties are
widely found in nature and have received much attention given
their diversity in biological activities.8 In particular, 8-hydroxy-
quinolines exhibit bioactivities, such as antifungal,9 anticancer,10
and HIV-1 replication inhibitors,11 and are very useful as important
key intermediates for pharmaceuticals. 8-hydroxyquinolines are
also used as a bidentate chelating reagent, and the complexes with
aluminium(III) have been found to be organic light-emitting
diodes.12
Herein we report the synthesis of 6-acyl-5,8-quinolinediols by
photo-Friedel–Crafts acylation of quinoline-5,8-dione using sun-
light as the energy source (Eq. 1).
ð1Þ
These reported acylation results encouraged us to investigate
the application of the solar driven reaction using quinoline-5,8-
dione 1 (Eq. 1). The initial investigation under artificial light with
1 and n-butanal was reported in 1988,7 however, the products
Results and discussion
Quinoline-5,8-dione 1 was synthesized from 8-hydroxyquino-
line with phenyliodine diacetate (PIDA) in one-step.13 First, we
examined the reaction in a 35 mL Pyrex sealable reaction tube with
a 20 mL benzene solution of 1 mmol of quinoline-5,8-dione 1 and
⇑
Corresponding author. Tel.: +1 915 747 5360.
E-mail address: smito2@utep.edu (S. Mito).
0040-4039/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tetlet.2013.04.021

3148
F. De Leon et al. / Tetrahedron Letters 54 (2013) 3147–3149
10 mmol of benzaldehyde. The solution was degassed with nitro-
gen to avoid any oxidation reaction by oxygen. The reaction tube
was sealed and placed on the roof of our research building for
exposure to direct sunlight.14 The corresponding 6-benzoyl-5,8-
quinolinediol 2a was obtained in 64% yield after 5 days (Eq. 2).
Conclusion
We demonstrated the synthesis of 6-acyl-5,8-quinolinediols by
photo-Friedel–Crafts acylation of quinoline-5,8-dione with alde-
hyde using sunlight. The operation for this reaction is very simple
and easy to perform. Currently, we are working on their applica-
tions and carrying out the reactions in more environmentally
friendly conditions.
ð2Þ
Acknowledgments
This research was financially supported by the Welch Founda-
tion (Grant # AH-1745) and the University of Texas at El Paso (Uni-
versity Research Institute Award 2012). F.D. was supported by the
RISE program (NIGMS/NIH 2R25GM069621-09).
Photo-dimerization was reported with 1,4-benzoquinone,15
however, in our experiment, no photo-dimerization product was
observed. We also tried reactions in various solvents including: t-
BuOH and t-BuOH/acetone, and benzene gave us the best yields.
Then, we investigated the substrate scope in the same condition.
The results were summarized in Table 1. The acylation took place
regioselectively; only at 6-position, not at 7 position. The structure
was determined by NMR techniques including HMBC proton carbon
correlations.16 We used both aromatic and aliphatic aldehydes, and
the products were obtained in good yields. However, when we used
p-chloro- and p-nitrobenzaldehyde, the reactions did not proceed
even after 10 days. The reaction with p-bromobenzaldehyde afforded
the product in 12% yield (entry 6). This indicates that electron with-
drawing group on the benzene ring of benzaldehyde hindered the
reaction. The mechanism of the photoacylation has been reported
and the photoaddition is initiated by hydrogen abstraction from
the aldehyde moiety to the triplet excited quinone.3,17 Low yields
in our case can be explained by electron withdrawing groups inhib-
iting hydrogen abstraction from aldehydes.
Supplementary data
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.tetlet.2013.
04.021.
References and notes
1. (a) Klinger, H.; Standke, O. Ber. Dtsch. Chem. Ges. 1891, 24, 1340–1346; (b)
Klinger, H.; Kolvenbach, W. O. Ber. Dtsch. Chem. Ges. 1898, 31, 1214–1216.
2. Using UV lamp for this reaction: Kraus, G. A.; Kirihara, M. J. Org. Chem. 1992, 57,
3256–3257.
3. Recent review, see: Oelgemöller, M.; Mattay, J. The ‘‘Photochemical Friedel–
Crafts Acylation’’ of Quinones: from the beginnings of organic photochemistry
to modern solar chemical applications. In CRC Handbook of Organic
Photochemistry and Photobiology; Horspool, W. M., Lenci, F., Eds., 2nd ed; CRC
Press: Boca Raton, FL, USA, 2003; pp 88:1–89:45.
4. (a) Schiel, C.; Oelgemöller, M.; Mattay, J. Synthesis 2001, 1275–1279; (b) Schiel,
C.; Oelgemöller, M.; Ortner, J.; Mattay, J. Green Chem. 2001, 3, 224–228; (c)
Oelgemöller, M.; Schiel, C.; Fröhlich, R.; Mattay, J. Eur. J. Org. Chem. 2002, 2465–
2474; (d) Waske, P. A.; Mattay, J.; Oelgemöller, M. Tetrahedron Lett. 2006, 47,
1329–1332; (e) Oelgemöller, M.; Jung, C.; Mattay, J. Pure Appl. Chem. 2007, 79,
1939–1947; (f) Murphy, B.; Goodrich, P.; Hardacre, C.; Oelgemöller, M. Green
Chem. 2009, 11, 1867–1870.
The position of methoxy group on the benzene ring affects the
yield (Table 1, entries 3–5). We also tried the reactions of these
three aldehydes with 1,4-naphthoquinone 3, and the tendency is
the similar (Eq. 3, Table 2). Steric hindrance may be the reason
for varying the yields.
5. Jung, C.; Funken, K.-H.; Ortner, J. Photochem. Photobiol. Sci. 2005, 4, 409–411.
6. Benites, J.; Rios, D.; Diaz, P.; Valderrama, J. A. Tetrahedron Lett. 2011, 52, 609–
611.
7. Tachikawa, N. Chem. Express 1988, 3, 33–36.
8. Roth, H. J.; Fenner, H. Arzneistoffe, 3rd ed.; Deutscher Apotheker Verlag:
Stuttgart, 2000. pp 51–114.
ð3Þ
9. Musiol, R.; Jampilek, J.; Buchta, V.; Silva, L.; Niedbala, H.; Podeszwa, B.; Palka,
A.; Majerz-Maniecka, K.; Oleksyn, B.; Polanski, J. Bioorg. Med. Chem. 2006, 14,
3592–3598.
10. Chan, S. H.; Chui, C. H.; Chan, S. W.; Kok, S. H. L.; Chan, D.; Tsoi, M. Y. T.; Leung,
P. H. M.; Lam, A. K. Y.; Chan, A. S. C.; Lam, K. H.; Tang, J. C. O. ACS Med. Chem.
Lett. 2013, 4, 170–174.
Table 1
Solar-Friedel–Crafts acylation with quinoline-5,8-dione18
11. Zouhiri, F.; Danet, M.; Bénard, C.; Normand-Bayle, M.; Mouscadet, J-. F.; Leh, H.;
Thomas, C. M.; Mbemba, G.; d’Angelo, J.; Desmaële, D. Tetrahedron Lett. 2005,
46, 2201–2205.
Entry
RCHO
Product
Time (in days)
Yield (%)
1
2
3
4
5
6
7
8
Ph
2a
2b
2c
2d
2e
2f
2g
2h
2i
5
4
4
4
5
4
4
5
4
4
4
64
58
41
45
47
12
67
71
68
60
62
12. (a) Tang, C. W.; VanSlyke, S. A. Appl. Phys. Lett. 1987, 51, 913–915; (b) Burrows, P.
E.; Sapochak, L. S.; McCarty, D. M.; Forrest, S. R.; Thompson, M. E. Appl. Phys. Lett.
1994, 64, 2718–2720; (c) Katakura, R.; Koide, Y. Inorg. Chem. 2006, 45, 5730–
5732; (d) Montes, V. A.; Pohl, R.; Shinar, J.; Anzenbacher, P., Jr. Chem. Eur. J. 2006,
12, 4523–4535; (e) Wang, J.; Oyler, K. D.; Bernhard, S. Inorg. Chem. 2007, 46,
5700–5706; (f) Fukushima, T.; Kaji, H. Org. Electron. 2012, 13, 2985–2990.
13. Barret, R.; Daudon, M. Tetrahedron Lett. 1990, 31, 4871–4872.
14. The University of Texas at El Paso (UTEP) is located: at latitude: 31.80°N,
longitude: 106.40°W, Elevation: 1219 m above sea level. El Paso is one of the
sunniest cities in the US with over 300 days of sunshine per year (83%), making
our institution an ideal place to investigate solar-driven synthesis.
15. Oelgemöller, M.; Schiel, C.; Fröhlich, R.; Mattay, J. Eur. J. Org. Chem. 2002, 15,
2465–2474.
p-MeC6H4
o-MeOC6H4
m-MeOC6H4
p-MeOC6H4
p-BrC6H4
Me
Et
i-Pr
C7H15
9
10
11
2j
2k
C11H23
16. We confirmed the regioselectivity by NMR technique. We assigned all proton
and carbon peaks of 2g by 1H, 13C, DEPT and HMQC. Then the HMBC correlation
showed the compound is 6-acylated. Also, preliminary X-ray analysis showed
2b as 6-acylated compound.
Table 2
Solar-Friedel–Crafts acylation with naphthoquinone
Entry
RCHO
Product
Time (in days)
Yield (%)
1
2
3
o-MeOC6H4
m-MeOC6H4
p-MeOC6H4
4a
4b
4c
4
5
4
50
51
72

F. De Leon et al. / Tetrahedron Letters 54 (2013) 3147–3149
3149
17. Maruyama, K.; Osuka, A. Recent Advances in the Photochemistry of Quinones
In The Chemistry of the Quinonoid Compounds; Patai, S., Rappoport, Z., Eds.; John
Wiley & Sons: New York, 1988; Vol. 2, pp 759–878. Chapter 13.
142.05, 133.69, 121.59, 120.71, 113.33, 107.04, 27.18. IR (neat, cmꢀ1
3332 (OH), 3032, 2924 (CH), 1668 (C@O), 1601, 1579, 1501, 1368, 1310, 1234,
1120, 1079, 673.
)
mmax
18. General procedure for synthesis of 7-acyl-5,8-quinolinediols.
In a 35 mL Pyrex sealable reaction tube, a solution of 1 mmol of the quinone
and 10 mmol of the aldehyde with 20 mL benzene is prepared and degassed
with nitrogen. The reaction tube is then sealed and placed on the roof for
exposure to direct sunlight. A magnetic stir plate was used to allow constant
mixing/stirring of the solution. The reaction mixture was then checked by TLC.
Column Chromatography using ethylacetate/hexanes mixture as the eluent
afforded the desired products.
6-Propanoyl-5,8-quinolinediol (2h)
Mp = 158–160 °C. 1H NMR (600 MHz, CDCl3): d 13.56 (s, 1H), 8.89 (s, 1H), 8.74
(d, J = 8.2 Hz, 1H), 7.64 (s, 1H), 7.50 (dd, J = 8.2, 6.0 Hz, 1H), 7.36 (s, 1H), 3.07 (q,
J = 7.2 Hz, 2H), 1.27 (t, J = 7.2 Hz, 3H).13C NMR (150 MHz, CDCl3): d 206.69,
154.85, 151.32, 143.86, 141.92, 133.66, 121.55, 120.82, 112.86, 106.35, 31.56,
8.17. IR (neat, cmꢀ1
) mmax 3332 (OH), 2984, 2852 (CH), 1631 (C@O), 1582, 1404,
1378, 1341, 1290, 1236, 1197, 1136, 1082, 651.
6-(2-Methylpropanoyl)-5,8-quinolinediol (2i)
6-Benzoyl-5,8-quinolinediol (2a)
Mp = 101–103 °C. 1H NMR (600 MHz, CDCl3) d 13.78 (s, 1H), 8.89 (dd, J = 4.2,
1.8 Hz, 1H), 8.75 (dd, J = 8.2, 1.6 Hz, 1H), 7.62 (s, 1H), 7.51 (dd, J = 8.2, 4.1 Hz,
1H), 7.39 (s, 1H) , 3.61–3.55 (m, 1H), 1.29 (s, 3H), 1.28 (s, 3H). 13C NMR
(150 MHz, CDCl3) d 207.26, 155.82, 151.41, 143.84, 141.97, 133.68, 121.53,
Mp = 176–178 °C. 1H NMR (600 MHz, CDCl3): d 13.39 (s, 1H), 8.93 (dd, J = 4.1,
1.6 Hz, 1H), 8.82 (dd, J = 8.2, 1.6 Hz, 1H), 7.72 (d, J = 8.2 Hz, 2H), 7.60–7.58 (m,
2H), 7.56–7.51 (m, 3H), 7.27 (s, 1H). 13C NMR (150 MHz, CDCl3): d 201.26,
156.3, 151.70, 143.46, 141.98, 137.92, 133.70, 131.86, 130.27, 128.98, 128.43,
121.00, 111.91, 106.46, 35.51, 30.83, 19.08. IR (neat, cmꢀ1
) mmax 3337 (OH),
121.60, 120.82, 119.8, 112.82, 109.48. IR (neat, cmꢀ1
)
mmax 3319, 3074 (OH),
2988, 2852 (CH), 1629 (C@O), 1603, 1584, 1503, 1402, 1289, 1273, 1202, 1032,
1022, 654.
1734 (C@O), 1613, 1578, 1502, 1405, 1323, 1298 (C–O), 1241, 1214, 1028, 663.
6-(4-Methylbenzoyl)-5,8-quinolinediol (2b)
6-Octanoyl-5,8-quinolinediol (2j)
Mp = 187–189 °C. 1H NMR (600 MHz, CDCl3): d 13.43 (s, 1H), 8.92 (dd, J = 4.1,
1.6 Hz, 1H), 8.81 (dd, J = 8.2, 1.6 Hz, 1H), 7.65 (d, J = 8.2 Hz, 2H), 7.6 (s, 1H),
7.55–7.53 (m, 1H), 7.32 (d, J = 7.4 Hz, 2H), 7.30 (s, 1H), 2.46 (s, 3H). 13C NMR
(150 MHz, CDCl3): d 200.95, 156.07, 151.57, 143.40, 142.67, 141.86, 135.18,
Mp = 100–102 °C. 1H NMR (600 MHz, CDCl3): d 13.59 (s, 1H), 8.77 (d, J = 4.1 Hz,
1H), 8.62 (d, J = 8.2 Hz, 1H), 7.62 (s, 1H), 7.39 (m, 1H), 7.24 (s, 1H), 2.88 (t,
J = 7.5 Hz, 2H), 1.67–1.64 (m, 2H), 1.31–1.13 (m, 8H), 0.77 (t, 3H). 13C NMR
(150 MHz, CDCl3): d 206.71, 155.04, 151.32, 143.80, 141.92, 133.64, 121.5,
120.83, 112.96, 106.58, 39.01, 31.66, 30.82, 29.27, 29.06, 22.58, 14.01. IR (neat,
133.65, 129.28, 129.08, 121.52, 120.76, 112.94, 109.62, 21.6. IR (neat, cmꢀ1
)
mmax 3315 (OH), 2923 (CH), 1636 (C@O), 1604, 1590, 1576, 1494, 1324, 1288,
cmꢀ1
) mmax 3343 (OH), 2925, 2852 (CH), 1634 (C@O), 1583, 1503, 1453, 1405,
1236, 1208, 1178, 1043, 657.
1267, 1184, 1059, 631.
6-(2-Methoxylbenzoyl)-5,8-quinolinediol (2c)
6-Dodecanoyl-5,8-quinolinediol (2k)
Mp = 151–153 °C. 1H NMR (600 MHz, CDCl3): d 13.48 (s, 1H), 8.91 (dd, J = 4.2,
1.6 Hz, 1H), 8.81 (m, 1H), 8.77 (dd, J = 1.2, 4.2 Hz, 1H), 7.47 (m, 1H), 7.41–7.32
(m, 3H), 6.97 (s, 1H), 6.95 (d, J = 8.2 Hz, 1H), 3.79 (s, 3H). 13C NMR (150 MHz,
Mp = 107–109 °C. 1H NMR (600 MHz, CDCl3): d 13.64 (s, 1H), 8.89 (dd, J = 1.6,
3.7 Hz, 1H), 8.75 (dd, J = 9.1, 1.6 Hz, 1H), 7.63 (s, 1H), 7.52–7.49 (m, 1H), 7.36 (s,
1H), 3.00 (t, 2H), 1.77 (m, 2H), 1.43–1.25 (m, 16H), 0.86 (t, J = 7.4 Hz, 3H). 13C
NMR (150 MHz, CDCl3): d 206.74, 155.07, 151.33, 143.81, 141.94, 133.66,
121.53, 120.84, 112.98, 106.55, 39.04, 31.88, 31.55, 30.84, 29.58, 29.47, 29.41,
CDCl3):
d 207.15, 156.34, 155.69, 151.53, 147.99, 143.47, 142.13, 133.70,
131.97, 128.60, 121.39, 120.69, 114.16, 111.47, 109.62, 55.63. IR (neat, cmꢀ1
)
mmax 3330 (OH), 3075, 2837 (CH), 1721 (C@O), 1645, 1598, 1502, 1401, 1329,
29.31, 24.53, 22.65, 14.06. IR (neat, cmꢀ1
) mmax 3349 (OH), 2956, 2852 (CH),
1299, 1284, 1191, 1180, 1075, 651.
1635 (C@O), 1581, 1505, 1412, 1385, 1342, 1329, 1264, 1235, 1183, 1018, 650.
1,4-Dihydroxy-2-(2-methoxybenzoyl)-naphthalene (4a)
6-(3-Methoxylbenzoyl)-5,8-quinolinediol (2d)
Mp = 147–149 °C. 1H NMR (600 MHz, CDCl3): d 13.4 (s, 1H), 8.94 (dd, J = 4.1,
1.6 Hz, 1H), 8.82 (dd, J = 8.2, 1.6 Hz, 1H), 8.77 (dd, 1H), 7.56 (m, 1H), 7.49–7.42
(m, 2H), 7.30 (s, 1H), 7.24 (s, 1H), 7.14 (m, 1H), 3.88 (s, 3H). 13C NMR (150 MHz,
Mp = 176–178 °C. 1H NMR (600 MHz, CDCl3): d 13.60 (s, 1H), 8.51 (d, J = 8.8 Hz,
1H), 8.08 (d, J = 8.2 Hz, 1H), 7.68 (ddd, J = 8.3, 6.9, 1.3 Hz, 1H), 7.59 (ddd, J = 8.2,
6.9, 1.2 Hz, 1H), 7.48 (ddd, J = 8.4, 7.5, 1.8 Hz, 1H), 7.31 (dd, J = 7.4, 1.7 Hz, 1H),
7.06 (t, J = 7.4 Hz, 1H), 7.01(d, J = 8.2 Hz, 1H), 6.57 (s, 1H), 3.78 (s, 3H). 13C NMR
(150 MHz, CDCl3): d 201.08, 158.21, 156.39, 142.63, 135.7, 134.12, 132.8,
131.65, 129.9, 128.64, 126.40, 124.68, 121.61, 120.60, 112.85, 111.50, 107.98,
CDCl3):
133.72, 129.46, 121.46, 120.75, 117.97, 113.81, 112.86, 109.52, 55.49. IR (neat,
cmꢀ1
mmax 3504, 3341 (OH), 2923 (CH), 1737 (C@O), 1632, 1583, 1400, 1346,
d 201.09, 159.65, 156.31, 151.72, 148.27, 143.48, 142.02, 139.15,
)
1302, 1180, 1118, 1095, 653.
55.75. IR (neat, cmꢀ1
) mmax 3288 (OH), 2936, 2836 (CH), 1633 (C@O), 1588,
6-(4-Methoxylbenzoyl)-5,8-quinolinediol (2e)
1507, 1488, 1355, 1240, 1161, 1045, 1023, 659.
1,4-Dihydroxy-2-(3-methoxybenzoyl)-naphthalene (4b)
Mp = 157–159 °C. 1H NMR (600 MHz, CDCl3): d 13.33 (s, 1H), 8.92 (d, J = 2.4 Hz,
1H), 8.8 (m, 1H), 7.77 (d, J = 8.2 Hz, 2H), 7.61 (s, 1H), 7.54 (m, 1H), 7.33 (s, 1H),
7.01 (d, J = 9.1 Hz, 2H), 3.9 (s, 3H). 13C NMR (150 MHz, CDCl3): d 206.78, 162.91,
155.82, 151.48, 148.22, 143.37, 141.74, 133.64, 131.70, 131.26, 121.53, 120.80,
Mp = 142–144 °C. 1H NMR (600 MHz, CDCl3): d 13.53 (s, 1H), 8.50 (d, J = 8.3 Hz,
1H), 8.11 (d, J = 8.3 Hz, 1H), 7.70 (t, J = 6.6 Hz, 1H), 7.60 (t, J = 6.6 Hz, 1H), 7.40
(t, J = 7.4 Hz, 1H), 7.2 (s, 1H), 7.1 (dd, J = 8.2, 2.4 Hz, 1H), 6.88 (s, 1H), 4.90 (s,
1H), 3.85 (s, 3H). 13C NMR (150 MHz, CDCl3): d 200.57, 159.56, 158.79, 142.54,
139.52, 130.08, 129.37, 126.59, 126.10, 124.66, 121.71, 121.26, 117.54, 113.76,
113.80, 109.61, 108.92, 55.52. IR (neat, cmꢀ1
) mmax 3164 (OH), 3076 (CH), 2935,
2845 (CH), 1738 (C@O), 1594, 1501, 1404, 1318, 1242, 1190, 1119, 1025, 670.
6-(4-Bromobenzoyl)-5,8-quinolinediol (2f)
111.45, 107.98, 55.49. IR (neat, cmꢀ1
) mmax 3325 (OH), 3063, 2988 (CH), 1633
Mp = 160–162 °C. 1H NMR (600 MHz, CDCl3): d 13.29 (s, 1H), 8.85–8.79 (m,
2H), 8.52 (m, 1H), 7.94 (d, J = 6 Hz, 1H), 7.63–7.58 (m, 2H), 7.21 (s, 1H), 6.99 (d,
J = 6 Hz, 1H), 6.8 (d, J = 6 Hz, 1H). 13C NMR (150 MHz, CDCl3): d 200.0, 151.94,
150.02, 148.32, 133.24, 131.87, 131.72, 130.9, 130.68, 128.84, 123.62, 121.84,
(C@O), 1559, 1508, 1492, 1287, 1240, 1197, 1043, 1029, 661.
1,4-Dihydroxy-2-(4-methoxybenzoyl)-naphthalene (4c)
Mp = 130–132 °C. 1H NMR (600 MHz, CDCl3): d 13.51 (s, 1H), 8.5 (d, J = 8.3 Hz,
1H), 8.12 (d, J = 8.2 Hz, 1H), 7.73–7.68 (m, 3H), 7.59 (t, J = 7.4 Hz, 1H), 6.99 (d,
J = 9.1 Hz, 2H), 6.94 (s, 1H), 4.89 (s, 1H), 3.88 (s, 3H). 13C NMR (150 MHz,
120.88, 109.78, 109.24, 109.12. IR (neat, cmꢀ1
) mmax 3294 (OH), 2921 (C–H),
1676 (C@O), 1585, 1501, 1455, 1297, 1069, 1190, 1119, 997, 757.
6-Acetyl-5,8-quinolinediol (2g)
CDCl3):
129.20, 126.47, 126.15, 124.57, 121.64, 113.67, 111.63, 108.33, 55.47. IR (neat,
cmꢀ1
mmax 3465.88 (OH), 3054, 2925 (CH), 1631, 1590, 1511, 1462, 1451,
1418, 1359, 1326, 970, 949, 867, 779, 763, 720.
d 199.45, 162.58, 158.24, 142.50, 132.20, 131.45, 130.71, 129.78,
Mp = 143–145 °C. 1H NMR (600 MHz, CDCl3): d 13.49 (s, 1H), 8.90 (dd, J = 5.7,
1.6 Hz, 1H), 8.75 (dd, J = 9.0, 1.6 Hz, 1H), 7.63 (s, 1H), 7.52 (m, 1H), 7.33 (s, 1H),
2.68 (s, 3H). 13C NMR (150 MHz, CDCl3): d 204.27, 154.98, 151.45, 143.88,
)