1
60
J.E. Nycz, G.J. Malecki / Journal of Molecular Structure 1032 (2013) 159–168
are interesting ligands in coordination chemistry as a N and/or O
atom donors [4–9].
116.6, 124.2, 126.3, 130.6, 136.6, 139.8, 157.7, 161.2, 174.6;
C{ H} NMR (CF CO D; 100.5 MHz) d = 19.7, 112.9, 118.7, 126.3,
3 2
1
3
1
We reported new synthetic routes for the aforementioned com-
pounds with in-depth spectroscopic characterization. Computa-
tional and spectroscopic studies were carried out to compare
selected carboxylic acids and their fluoro-, thio-, and dithioderiva-
tives, which have not been reported by previous studies.
128.7, 129.6, 131.3, 146.9, 152.5, 159.4, 173.0 [12]; CCDC 806597.
8-Hydroxyquinoline-7-carboxylic acid (2b) (yellow) 7.18 g
(38 mmol, 38%), mpdec. = 258 °C (lit. 248–250 °C [13]); H NMR
1
(Pyridine-d
5
; 400.1 MHz) d = 7.30 (d, JHH = 8.7 Hz, 1H, aromatic),
7.41 (dd,
J
HH = 8.3 Hz, HH = 4.1 Hz, 1H, aromatic), 8.11 (dd,
J
J
HH = 8.3 Hz, JHH = 1.6 Hz, 1H, aromatic), 8.36 (d, JHH = 8.6 Hz, 1H,
1
aromatic), 9.03 (dd, JHH = 4.0 Hz, JHH = 1.3 Hz, 1H, aromatic);
NMR (KOD/D O; 400.1 MHz) d = 6.89 (d, JHH = 8.4 Hz, 1H, aro-
matic), 7.36 (dd, JHH = 8.2 Hz, JHH = 4.2 Hz, 1H, aromatic), 7.53 (d,
H
2
. Experimental
2
2
.1. General
J
HH = 8.4 Hz, 1H, aromatic), 8.09 (d, JHH = 8.2 Hz, 1H, aromatic),
1
3
1
8
1
1
.60 (d, JHH = 3.0 Hz, 1H, aromatic); C{ H} NMR (Pyridine-d
5
;
NMR spectra were obtained with Bruker Avance 400 and 500
00.5 MHz) d = 112.4, 116.5, 123.4, 127.4, 132.5, 136.0, 140.6,
1
13
19
operating at 400.13 MHz ( H), 100.5 MHz ( C), 188.3 MHz ( F)
and 470.5 MHz ( F) at 21 °C; chemical shifts referenced to ext.
TMS ( H, C) or DSS ( H, C), and CFCl ( F); coupling constants
3
are given in Hz. The H and C NMR calculations were performed
with the ACD Labs NMR Predictor v.12 program considering the
13
1
48.9, 161.8, 174.5;
2
C{ H} NMR (KOD/D O; 100.6 MHz)
1
9
d = 110.68, 121.97, 122.24, 128.36, 131.17, 136.89, 143.43,
47.21, 161.96, 178.82.
-Fluoro-8-hydroxy-2-methylquinoline-7-carboxylic acid (2c)
1
13
1
13
19
1
1
13
5
1
(
yellow) 5.30 g (24 mmol, 24%), mpdec. = 199 °C; H NMR (KOD/
O; 400.2 MHz) d = 2.47 (s, 3H, CH ), 7.01 (d, JHF = 11.2 Hz, 1H, H-
quinoline), 7.11 (d, JHH = 8.5 Hz, 1H, H-quinoline), 7.86 (d, JHH
influence of different solvents (Pyridine, DMSO, CF
Mass spectra were obtained with a MASPEC II system [II32/
9D9], Varian MAT 711, Varian 500 MS and Finnigan MAT 95
Finnigan MAT GmbH, Brema); in EI mode (70 eV) and, where nec-
3 2 2
CO D or D O).
D
2
3
=
9
(
13
1
8
.5 Hz, 1H, H-quinoline); C{ H} NMR (KOD/D
2
O; 100.6 MHz)
d = 23.72, 109.12 (d, JCF = 20.5 Hz), 116.71 (d, JCF = 6.4 Hz), 119.07
d, JCF = 18.6 Hz), 123.08, 129.39 (d, JCF = 3.2 Hz), 140.24, 146.86 (d,
essary, FAB or ESI technique was applied. EPR spectra in the X-band
were recorded with a Bruker System EMX. FTIR spectra were re-
corded on a Perkin Elmer spectrophotometer in the spectral range
(
19
1
JCF = 237.6 Hz), 156.05, 157.85, 176.46; F{ H} NMR (KOD/D
2
O;
+
4
70.5 MHz) d = À140.57; MS: (ESI) (M+H) = 222 (33%),
À1
4
000–450 cm with the samples in the form of KBr pellets. Elec-
+
(
C
M+Na) = 244 (50%); E.A. [Found C, 59.43; H, 3.68; N, 6.30;
FNO requires C, 59.73; H, 3.65; N, 6.33%].
e was synthesized according to procedure described in the lit-
erature [10].
-Hydroxy-2-methylquinoline-6-carboxylic acid (2e) (yellow)
tronic spectra were measured on a spectrophotometer Lab. Alli-
ance UV–Vis 8500 in the range 500–180 nm in CH Cl solution.
Chromatography was carried out on Silica Gel 60 (0.15–0.3 mm)
Machery Nagel. Melting points were determined on MPA100
OptiMelt melting point apparatus and uncorrected. 8-Hydroxy-
H
11 8
3
2
2
2
5
1
mpdec. = 210 °C; H NMR (DMSO-d
CH ), 7.18 (d, JHH = 8.8 Hz, 1H, aromatic), 7.53 (d, JHH = 8.5 Hz, 1H,
aromatic), 8.04 (d, JHH = 8.8 Hz, 1H, aromatic), 8.76 (d, JHH = 8.3 Hz,
1
7
6
; 400.1 MHz) d = 2.74 (s, 3H,
2
2
-methylquinoline (1a), 8-hydroxyquinoline (1b) and 8-hydroxy-
-aminoquinoline (1d) were purchased from Sigma–Aldrich, and
3
were used without further purification. Compound 2e was synthe-
sized according to procedure described in the literature [10].
1
H, aromatic); H NMR (CF
3 2 3
CO D; 400.1 MHz) d = 3.38 (s, 3H, CH ),
.97 (d, JHH = 9.1 Hz, 1H, aromatic), 8.15 (d, JHH = 8.7 Hz, 1H, aro-
matic), 8.85 (d, JHH = 9.1 Hz, 1H, aromatic), 9.72 (d, JHH = 8.7 Hz,
1
3
1
2.1.1. Synthesis of carboxylic acids 2a, 2b and 2e
1H, aromatic);
6
C{ H} NMR (DMSO-d ; 100.5 MHz) d = 23.0,
To the solution of 1a, 1b or 1c (100 mmol) in THF (200 mL), Bu-
109.4, 110.9, 120.5, 121.3, 133.0, 137.3, 147.0, 159.8, 164.7, 171.5
t
13
1
OK was added (11.2 g, 100 mmol), respectively. The reaction mix-
ture was vigorously stirred under reflux for an hour. The volatiles
were evaporated and the residue was dissolved in dry DMF
[12];
5
C{ H} NMR (Pyridine-d ; 100.5 MHz) d = 25.3, 108.3,
118.5, 118.9, 121.2, 129.7, 132.2, 151.7, 161.4, 161.5, 174.1 [12]);
1
3
1
3 2
C{ H} NMR (CF CO D; 100.5 MHz) d = 19.6, 108.4, 109.8, 119.9,
(
100 mL) followed by heating the reaction mixture to 115 °C. Sub-
122.4, 136.0, 141.4, 143.7, 160.6, 161.2, 173.5 [12].
sequently, dry CO was passed through the reaction mixture for 3 h
2
in the temperature range 115–120 °C. The reaction mixture was
cooled down to room temperature and the residue was acidified
by water solution of hydrochloric acid (1%), and was filtered off.
The solid was dissolved in water solution of K CO with further fil-
2 3
tration. The water layer was acidified by water solution of hydro-
chloric acid (1%), and the solid was filtered. The crude product
2.1.2. Synthesis of carboxylic acid 2d
1a (10 mmol) was dissolved in pyridine (50 mL), and SeO
2
(10 mmol) was added followed by stirring at 90 °C for 16 h. During
reaction a sample of the reaction mixture was investigated by EPR
spectroscopy. Subsequently, reaction mixture was filtered off. The
volatiles were evaporated and the residue was dissolved in aque-
ous KOH solution (10%), and residual solid was filtered off. The fil-
tered liquid was acidified by water solution of hydrochloric acid
(10%). Then the filtered crude product was purified at Soxlet appa-
ratus by AcOEt.
was dried over P
tus (AcOEt).
4
O10 and purified by extraction at Soxhlet appara-
8
-Hydroxy-2-methylquinoline-7-carboxylic acid (2a) (yellow)
1
1.98 g (59 mmol, 59%), mpdec. = 206–207 °C (lit. 206–208 °C
1
[
(
7
11]; H NMR (DMSO-d
d, JHH = 8.6 Hz, 1H, aromatic), 7.69 (d, JHH = 8.5 Hz, 1H, aromatic),
.86 (d, JHH = 8.6 Hz, 1H, aromatic), 8.52 (d, JHH = 8.5 Hz, 1H, aro-
6
; 400.1 MHz) d = 2.80 (s, 3H, CH
3
), 7.20
Quinoline-8-hydroxy-2-carboxylic acid (2d) (yellow) 1.02 g
(54 mmol, 54%), mpdec. = 215–216 °C (lit. mpdec. = 216–217 °C
1
[14]); H NMR (DMSO-d
6
) d = 7.25 (d, J = 9.0 Hz, 1H, aromatic),
1
matic) [11]; H NMR (Pyridine-d
CH ), 7.29 (d, JHH = 8.4 Hz, 1H, aromatic), 7.30 (d, JHH = 8.7 Hz, 1H,
aromatic), 8.01 (d, JHH = 8.4 Hz, 1H, aromatic), 8.29 (d, JHH = 8.6 Hz,
5
; 400.1 MHz) d = 2.70 (s, 3H,
7.54 (d, J = 7.5 Hz, 1H, aromatic), 7.65 (t, J = 7.4 Hz, 1H, aromatic),
8.18 (d, J = 9.0 Hz, 1H, aromatic), 8.58 (d, J = 9.0 Hz, 1H, aro-
matic); 10.25 (br. s, 1H, OH) [14];
d = 111.98, 117.56, 119.92, 129.89, 130.42, 136.43, 138.29,
144.23, 153.80, 165.10 [14]; MS: (FAB) (M+H) = 190.
3
1
3
1
6
C{ H} NMR (DMSO-d )
1
1
H, aromatic); H NMR (CF
3
CO
2
D; 400.1 MHz) d = 3.49 (s, 3H, CH
3
),
+
8
.09 (d, JHH = 8.8 Hz, 1H, aromatic), 8.35 (d, JHH = 8.7 Hz, 1H, aro-
matic), 8.71 (d, JHH = 8.8 Hz, 1H, aromatic), 9.26 (d, JHH = 8.7 Hz,
1
3
1
1
H, aromatic);
C{ H} NMR (DMSO-d
6
; 100.5 MHz) d = 22.6,
2.1.3. EPR experiments
1
13.2, 113.4, 125.5, 128.0, 130.9, 135.5, 141.4, 156.9, 161.2, 171.2
1a, 1d, 2a or 2e (10 mmol) was dissolved in pyridine (50 mL),
and SeO (10 mmol) was added followed by stirring at 90 °C for
2
1
3
1
[
12];
C{ H} NMR (Pyridine-d
5
;
100.5 MHz) d = 24.7, 112.9,