A. Skotnicka et al. / Journal of Molecular Structure 977 (2010) 12–16
15
Table 2
4. Experimental
13C NMR chemical shifts (d) of ortho-formylphenols and of the respective Li, Na, and K
phenolates for 0.5 M solutions in DMSO-d6 at 30 °C (data for the carbon atoms in the
rings B, e.g. C10, and C, e.g. C10, are always given in the second and third row,
respectively).
4.1. Compounds
Compounds 1H and 2H are commercial products. Aldehydes 3H,
4H, and 5H are these used by us recently [3].
Cl
C2
C3
C4
C5
C6
CHO
1H
ILi
122.18
123.85
160.92
174.32
117.31
124.38
136.39
135.70
119.54
109.54
130.31
135.70
192.93
192.17
124.77a 175.28a 124.95a 136.11a 110.08a 136.87a 192.83a
4.2. Lithium and sodium ortho-formylphenolates
INa
IK
123.47
123.83
169.11
174.85
120.88
124.21
135.63
135.05
113.60
108.99
128.19
127.50
190.81
190.21
Pieces of lithium or sodium (5 mmol) were added to the alde-
hyde (5 mmol) dissolved in dry diethyl ether (15 mL). Reaction
mixture was refluxed and stirred even for few days until all metal
is consumed (the apparatus was protected from the moisture with
a trap filled with granulated anhydrous calcium chloride). The sol-
vent was distilled off and product recrystallized from 95% ethanol.
It was then dried in the vacuum desiccator over the sodium
hydroxide pellets.
125.17a 179.16a 127.06a 135.21a 106.63a 127.82a 190.73a
2H
112.37
122.01
112.50
121.91
163.89
129.15
170.19
128.42
180.39
127.19
180.45
126.92
160.06
123.41
173.05
125.34
175.27
125.27
161.35
123.59
155.64
129.23
165.77
127.98
156.06
129.19
173.16
126.31
162.89
124.45
128.27
163.68
124.51
128.20
164.50
124.56
128.11
118.68
124.12
122.81
122.29
129.92
119.31
130.23
118.80
124.26
124.26
131.73
131.73
133.41
133.41
125.07
125.07
110.62
125.98
112.72
124.75
110.68
125.96
113.90
123.60
123.98
123.98
125.18
124.51
124.51
124.88
124.25
124.25
124.56
138.27
128.73
37.40
128.73
127.51
126.00
126.00
123.65
123.65
123.34
123.34
119.24
127.79
109.49
126.60
107.55
126.44
118.29
127.67
126.82
131.69
131.69
133.12
133.12
135.58
135.58
135.67
135.67
125.90
130.28
123.12
128.87
127.01
128.13
125.73
130.06
131.94
192.81
191.37
189.60
189.18
195.63
189.34
187.68
194.85
192.19
193.85
192.13
194.12
195.53
2Li
128.28
136.01
127.50
135.67
127.24
137.09
137.09
138.27
138.27
138.59
138.59
137.22
137.22
137.42
137.42
139.43
139.43
137.52
137.52
140.76
140.76
134.30
134.30
123.53
134.34
134.34
123.44
134.37
134.37
123.33
2Na 112.38
121.71
2K
3H
3Li
112.09
121.61
115.34
126.21
116.14
123.12
4.3. Potassium ortho-formylphenolates
Solutions of aldehyde (5 mmol) in hot 95% ethanol (15 mL) and
potassium hydroxide (5 mmol) in the same solvent (15 mL) were
combined and refluxed for 1 h. Part of the solvent (10 mL) was dis-
tilled off. The solid material precipitated after cooling of the resi-
due was washed with dry diethyl ether and dried in the vacuum
desiccator over the sodium hydroxide pellets. Unfortunately, this
procedure was not efficient to obtain 5K.
3Na 116.41
122.38
3K
4H
4Li
115.52
125.87
124.12
123.90
127.30
120.14
123.49
123.49
126.72
126.72
120.69
120.69
124.70
123.30
124.70
124.49
123.24
124.49
125.07
123.14
125.07
133.16
129.60
131.64
129.72
128.11
129.85
129.37
131.80
129.37
129.70
131.65
129.70
130.02
131.46
130.02
4Na 124.29
123.81
4.4. NMR spectroscopy
4K
5H
129.12
116.85
108.39
127.46
120.59
108.38
127.34
120.67
All NMR spectra were run for 0.5 M solutions in CDCl3 with Bru-
ker Avance DRX 500 NMR spectrometer operating at 500.13 MHz
for 1H and 126.77 MHz for 13C, and 194.37 MHz for 7Li, respec-
tively. The 1H and 13C chemical shifts are referenced to the trace
signal of CHCl3, 7.26 ppm from internal TMS, and to the centre
peak of CDCl3 heptet, 77.00 ppm from internal TMS, respectively.
The 7Li chemical shifts are referenced to the signal of an external
1 M aqueous LiCl in a 1 mm diameter capillary inserted coaxially
inside the 55 mm diameter NMR-tube. The PFG 1H, 13C HMQC
and HMBC spectra were run using standard pulse sequences,
hmqcgpqf and hmbcgplpndqf, from Bruker pulse library.
5Li
195.11
194.66
5Na 108.36
127.19
120.76
a
In DMF-d7 [33].
H
O
O
H
References
O
O
[1] R. Gawinecki, E. Kolehmainen, H. Loghmani-Khouzani, B. Os´miałowski, R.P.
Lovász, Eur. J. Org. Chem. (2006) 2817.
[2] J. Elguero, C. Marzin, A.R. Katritzky, P. Linda, The Tautomerism of Heterocycles
(Adv. Heterocycl. Chem., suppl. 1), Academic Press, New York, 1976.
´
[3] R. Gawinecki, A. Kuczek, E. Kolehmainen, B. Osmiałowski, T.M. Krygowski, R.
Kauppinen, J. Org. Chem. 72 (2007) 5598.
[4] P. Szczecin´ ski, A. Gryff-Keller, S. Molchanov, J. Org. Chem. 71 (2006) 4636.
[5] M. Raban, E. Noe, G. Yamamoto, J. Am. Chem. Soc. 99 (1977) 6527.
[6] M. Raban, D.P. Haritos, J. Am. Chem. Soc. 101 (1979) 5178.
syn
anti
Scheme 7. Syn and anti conformers of ortho-formylphenolate anion.
´
[7] J. Terpinski, W. Ke˛pys, Polish J. Chem. 53 (1979) 1597.
[8] P.A. Kollman, J.E. Liebman, L.C. Allen, J. Am. Chem. Soc. 92 (1970) 1142.
[9] A.B. Sannigrahi, T. Kar, B.G. Niyogi, P. Hobza, P.v. Ragué Schleyer, Chem. Rev. 90
(1990) 1061.
[10] S. Berski, Z. Latajka, Int. J. Quantum Chem. 90 (2002) 1108.
[11] T.M. Krygowski, J.E. Zachara-Horeglad, Theor. Chem. Acc. 14 (2005) 1229.
[12] T.M. Krygowski, J.E. Zachara, R. Moszyn´ ski, J. Chem. Inf. Model. 45 (2005) 1837.
[13] J. Kruszewski, T.M. Krygowski, Tetrahedron Lett. 13 (1972) 3839.
[14] T.M. Krygowski, J.E. Zachara, R. Moszyn´ ski, J. Chem. Inf. Comput. Sci. 33 (1993)
70.
3. Conclusions
There does not exist any clear effect on the 1H and 13C NMR
chemical shifts of salicylaldehyde caused via its O-substitution by
alkali metal cations. Although this is known, in benzoannulated
salicyladehydes the situation is different owing to p-electron delo-
[15] P.v. Ragué Schleyer, C. Maerker, A. Dransfeld, H. Jiao, N.J.R. van Eikema
Hommes, J. Am. Chem. Soc. 118 (1996) 6317.
calization, which is further reflected in their NMR parameters.
Among them 1H chemical shifts of hydroxyl proton and 13C chem-
ical shifts of hydroxyl and formyl bearing carbons are the most
useful ones showing most directly the changes in the aromatic
character in the intra-molecularly hydrogen bonded six-membered
quasi-ring of salicylaldehyde.
´
[16] T.M. Krygowski, J.E. Zachara, B. Osmiałowski, R. Gawinecki, J. Org. Chem. 71
(2006) 7678.
´
[17] M. Kalinowska, R. Swisłocka, Z. Ra˛czyn´ ska, J. Sienkiewicz, W. Lewandowski, J.
Phys. Org. Chem. 23 (2009) 37.
´
[18] M. Kalinowska, R. Swisłocka, W. Lewandowski, J. Mol. Struct. 792–793 (2006)
130.
[19] M. Palusiak, T.M. Krygowski, Chem. Eur. J. 13 (2007) 7996.